Medical and Healthcare Textiles 2007: Proceedings of the Fourth International Conference on Healthcare and Medical Textiles (Woodhead Publishing Series in Textiles)

Medical and heaithcare textiles 0 Woodhead Publishing Limited, 201 0 The Textile Institute and Woodhead Publishing T...

Author: J.F. Kennedy | S.C. Anand | M. Miraftab | S. Rajendran

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Medical and heaithcare textiles

0 Woodhead Publishing Limited, 201 0

The Textile Institute and Woodhead Publishing The Textile Institute is a unique organisation in textiles, clothing and footwear. Incorporated in England by a Royal Charter granted in 1925, the Institute has individual and corporate members in over 90countries. The aim of the Institute is to facilitate learning, recognise achievement, reward excellence and disseminate information within the global textiles, clothing and footwear industries. Historically,The Textile Institute has publishedbooks of interest to its members and the textile industry. To maintain this policy, the Institute has entered into partnership with Woodhead Publishing Limited to ensure that Institute members and the textile industry continue to have access to high calibm titles on textile science and technology. Most Woodhead titles on textiles are now published in collaboration with The Textile Institute. Through this arrangement, the Institute provides an Editorial Board which advises Woodhead on appropriate titles for future publication and suggests possible editors and authors for these books. Each book published under this arrangement carries the Institute’s logo. Woodhead books published in collaboration with The Textile Institute are offered to Textile Institute members at a substantial discount. These books, together with those published by The Textile Institute that are still in print, are offered on the Woodhead web site at: www.woodheadpublishing.com. Textile Institute books still in print are also available directly from the Institute’s website at: www.textileinstitutebooks.com. A list of Woodhead books on textile science and technology,most of which have been published in collaboration with The Textile Institute, can be found towards the end of the contents pages.


Woodhead Publishing Series in Textiles: Number 75

Medical and healt hcare textiles Edited by S. C. h a n d , J. F. Kennedy, M. Miraftab and S. Rajendran

TheXxtile Institute

CRC Press Boca Raton Boston New York Washington, DC

W O O D H E A DP U B L I S H I N G Oxford 0 W o o d h e a d Publishing Limited, 201 0

Cambridge

LIMITED New Delhi

published by Woodhead Publishiag Limited in assoCiation with The Textile Jnstitute Woodhead Publislung Limited,Abington Hall, GrardaPark,Great Abington Cambridge CB216Ay UK www.wOodheadpublishiug.com

Woodhead Publishing IndiaPrivate Limited, G-2, Vardiun House,7/28 Ansari Road,Daryagazj, New Delhi - 110002, India www.woodheadpublisbgindia.com Published in North America by CRC Press LLC, 6000 Broken Sound Parkway, NW, Suite 300, Boca Raton, FL 33487, USA

First published 2010, Woodhead Publishing Limited and CRC Press LLC Q woodhead Publishlug Limitd 2010 The authors have asserted their moral rights.

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iv


CONTENTS WoodheadPublishing Series in Textiles Preface

XiX

mii

PART I INFECTION CONTROL AND BARRIER MATERIALS Infedion control and barrier materirrls: an overview S Rajendran, University of Bolton, UK - Introduction - Wound infection - Hospital protective materials - Bibliography

3

Antimicrobial properties of silvercontaining chitosan fibers Y Qin and C Zhu, %Biochemical Materials Research and Development Cenlre, China - Introduction - Experimental - Results and discussion - Conclusions - References

7

Copperimpregnated anthkmbial textiles: an innovative weapon to fight infeetion G Borkow, A Felix and J Gabbay, Cupron Inc, USA - Copper as a biocide - Incorporationof copper oxide into natural and synthetic fibres - Biocidal properties of fabrics containing copper oxide - Clinical studies - Discussion - References

14

A review of the role of microwaves in the destruction of pathogenic bacteria A S Lamb and E Siores, University of Bolton, UK - Microwave interactions with materials - Fixed ftequency microwave interactions with bacteria - Work carried out at the University of Bolton Flowcytometry - Concluding remarks - References

23

Antimicrobial bioactive band-aids with prolonged and controlled action P Shndric, L Simovic, M Kostic, A Medovic, KMilosevic and S Dimitrijevic, University of Belgrade, Serbia - Introduction - Experimental - Experimental results and discussion - Conclusion - References

30

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~

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v

Comparison of antimicrobial textile treatments

38

E Smith, J T Williams, S E Walsh and P Painter, De Monij4orf University, UK - Introduction

-

Materials and methods Results and discussion Conclusions References

Evaluation of plasma-deposited anti-adhedive and anti-bacterial coatings on m e d i d textiles A J Paul, F Bretagnol, G Buyle, C Colin, 0 Lepanc and H Rauscher, C S M Ltd, UK Plasma treatment of textiles - X-ray photoelectron spectroscopy (XPS) - Time-of-flight secondary ion mass spectrometry (ToFSIMS) - References

48

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Controlling the spread of infectionsin hospital wards by the use of antimicrobials on medical textiles and surfaces W C White,AEGIS Environmental Management, USA.R. BellJield, Carrington Career and Workwear Ltd, U .J Ellis, Devan-PPT Chemicals Ltd UK and Ir P Vandendaele, Devan ChemicalsW,Belgium - Introduction Microorganisms - Antimicrobials - Organohctional silane antimicrobial technology - Verificationtechniques and safety profile - Potentialuses - Hospital blankets - Nonwoven surgical drapes - Wound care silk dressings - carpeting

55

-

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Uniforms - Siliconerubber

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Case study: the Arthur G. James Cancer Center Hospital and Research Institute

- summary

-

References

Inherenth antimicrobial alchite fibres developed for wound care applications MMiraftab, C Iwu, C Okoro and G Smart, Universityof Bolton, UK - Introduction - Productionmethodology - Results and discussions - Conclusions - References

Antimicrobialtextilea for health and hygiene applications based on eeo-friendly natural products M Joshi, R Purwar and S W Ali, Indian Institute of Technology, India and S R a j e d a n , Universityof Bolton, UK - Introduction vi


76

84

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Natural antimicrobial agents for textile substrates Antimicrobial finishing of textiles based on neem extract Conclusion References

-

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Investigation of the filtration properties of medical masks MAkulin, I Usta, D Kocak and M S Ozen, Marmara Universiw, Turkey - Introduction - Materials and method - Results Conclusion - References

93

Lint release charncteristia of nonwoven wipes V K Kothari and R Loganathan, Indian Institute of Technology, India - Introduction - Design of measurement apparatus Materials and methods - Results and discussion - Conclusions

98

-

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Development of antimicrobialpolyester uskg neem extract S Wazed Ali, B Gupta and M Joshi, Indian Institute of Technology, India - Introduction - Materials - Methods - Results and discussion - Conclusion - References Fixation of cationic antibacterialproducts before dyeing: a more ecological process R V Vieira, J G Santos, G A4 B Soares and J I N R Comes, University of Minho, Portugal - Introduction - Experimental

-

-

108

117

Results and discussion

Conclusions

- References

Preliminary studies into wash-fast antimicrobial treatments of polyester 0 H a w k NAllen, G C Lees, H Rowe and J Verran, Manchester Mefropolitan University, UK - Introduction - Background - Methodology - Results - Futurework - References 0 Woodhead Publishing Limited, 201 0

vii

122

Emyme-catalysedcoupling of functionalantioxidan@onto protein fibres S JUTand G MGuebitz, Technical University of Graz, Austria and V Kokol, University of Maribor, Slovenia - InttOdUCtiOn - Materials and methods - Results and discussion - Conclusions References

126

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PART II HEALTHCARE AND HYGIENE PRODUCTS 137

Healthcare and hygiene products: an overview

S C Anand, University of Bolton, UK

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Introduction Recentadvances References

Cellulosic materials for odor and pH control J K Dutkiewicz, Buckeye TechnologiesInc, USA Introduction - Experimentalmodel - Ammonia emission studies - FreshcomfortTMtechnology - Conclusions - References

140

Development of a high-absorbent sanitary napkin A Das, V K Kothari and S Makhva, Indian Institute of Technology, India - Introduction - Experimental Results and discussions - Conclusions - References

148

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Retention of anionic rurlactmt followinggarment handering and its potential effect on dermatitis suffererr H D Rowe, Manchester Metropolitan University, UK - Introduction - Experimental - Results - Discussion - Conclusions - References Preparation of protective disposable hygiene fabric8 for medical appIications MMontazer, Amirkabir University of Technology,Iran, F Rangchi, TehranAzad University,Iran and F Siavoshi, Tehran Universi& Iran introduction Experimental

156

164

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viii


-

-

Conclusions References

Development of surgical clothing from bamboo fibres K Ramachandralu, PSG College of Technologv, India - Introduction - Materials and methods - Results and discussions - Conclusions References

171

Thermal characterizationand mechanical properties of PLA y a m A MManich, MMarti and R MSauri, Spanish Councilfor Scientijk Research, Spain, D Cayuela, Technical University of Catalonia, Spain and M USS+ Universidade da Beira Interior, Portugal - Introduction - Materials - Methods - Results - Discussion and conclusions - References

181

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PART IIIWOUND CARE MATERIALS Wound care materials: an overview M Mirajlab, University of Bolton, UK - Introduction - Wounds: natural healing mechanisms versus wound care materials - Review of papers on wound w e materials - References

193

Controlled drug release from nanofibrona polyester materials M J Bide, University of Rhode Island, USA, M D Phaneuf and T M Phaneuf; BioSurfaces, USA and P JBrown, Clemson University, USA - Introduction - Experimental - Results - Conclusions - References

198

Development of odour (volatile molecule) adsorbent materials for healthcare G Lee, S C Anand and S Rajendran, Universityof Bolton, UK and I Walker, Lantor (VK)Ltd, UK - Introduction - Odour adsorbent materials - Experimental work - Results - Conclusions - References

206


ix

Development of a decision support system for determination of suitable dressings for wounds K G Karthick and M Miraftab, Universityof Bolton, UK and JAshton, Bolton Primary Care Trust, UK Introduction - Research amongst nursing staff - The need for a decision support system - Expert systems in medicine - Decision support system for wound dressing selection - Conclusion - References

215

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Treatment of cotton fabria with ethyl cellulose dcrocapsulea R Badulescu, University of Ploiesti, Romania and B Voncina, V Vivod and D Jausovec, University of Maribor, Slovenia - Introduction - Experimental - Results and discussion - Conclusions - References

226

Measuring interface pressure in compression garments for barns patients E Maklewska, A Navrocki, K Kowalski and W Tmowski, Institute of Knitting Technology and Techniques, Poland Introduction - Investigationmethods - Testmaterial - Test results and discussion - Conclusions - References

236

Psyllium: current and future applications R Mmood and MMiraftab, Universityof Bolton, UK

244

-

- Introduction

-

The psyllium plant

-

Physiochemical properties of psyllium Recent medical application of psyllium Other applications of psyllium Conclusions References

- History - Traditional food applications -

-

PART IV BANDAGING AND PRESSURE GARMENTS Bandaging and pressure garments: an overview S C A& University of Bolton, UK - Introduction - Causes of venous disorders x

257


- Factors which determine sub-bandage pressure

-

Classification of compressionbandages Recent advances in compression therapy Single-layer compressionbandages References

Biomaterials with controlled elasticity for post-operationrecovery M Carmen and E Alexandra, The National Institutefor Textile and Leather, Romania - Introduction - Testing cytotoxicity and sensitizing potential - Testing methods - Results: sensitizing and irritation potential - Conclusions - References A study of the pressure profde of compression bandager, and compression garments for treatment of venous leg ulcers MSikkq S Ghosh andA Mukhopadlyqy, National Institute of Technology,India - Introduction - Materials - Method - Results and discussion - Conclusions - References Development of t h r e e d mensional structures for singlelayer compression therapy S Rajendran and S C Anand, Universityof Bolton, UK - Introduction - The treatment of venous leg ulcers Compression systems - Problems with current bandages - 3D compression bandages - Materials and methods - Results and discussion - summary - References

263

272

279

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Intermittent pneumatic compressionand bandaging: the effects of external pressure applied over bandaging S Rithalia and A4 Leyden, University of Salford, UK - Introduction - Methods and materials - Results - Conclusions - References Physiological effects of Lycra@pressure garments on children with cerebd palsy JAttard Royal National Orthopaedic Hospital, UK and S Rithalia, Universityof Salford, UK - Introduction 0 Woodhead Publishing Limited, 201 0

xi

293

300

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-

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Cerebralpalsy ~ynami~ c ycra@ pressure garments Aims and objectives of study Method Results Discussion Conclusions References

Empirical modelling of elastic properties of pressure garments for healthcare S Pereira, S C Anand and S Rajendran, University of Bolton, UK and C Wood, BaltexLtd, UK - Introduction Experimental Results and discussion - Conclusions References

309

Investigation of elastic properties of multhxid warp knitted bandages MAkalin, D KoFak, S I Mistik and M Uzun, Marmara University, Turkey Introduction - Materials and methods Results - Conclusions - References

323

-

PART V IMPLANTABLE MATERIALS Implantable materials: an overview S Rqjendran, University of Bolton, UK - Introduction - vasculargrafts - Kneeimplants - Meshgrafts - SCafTOlds - Bibliography

329

Designing vena cava 6ltera with textile structure9 J Yoon and M W King, North Carolina State University, USA and E Johnson, Crux Biomedical Inc, USA - Introduction Current filters for embolic protection - Discussion - Conclusion - References

334

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xii


Application of polyvinylidenefluoride (PVDF) as a biomaterial in medical textiles S Houis and T Gries, R WTH Aachen University, Germany, E M Engelhardt and F Wurm, Ecole Polytechnique Fkdkrale de Lausanne, Switzerland Introduction - Stateoftheart - Production of medical textiles - Projects using PVDF for medical applications - Conclusion - References

342

-

Textile scaffolds for tissue engineering - near future or just vision? D Aibibu, S Houis, M S Harwoko and T Gries, RWTH Aachen Universiv, Germany - Introduction - Materials - Results - Discussion - References

353

Visible invisibility: contamination-aware textile surface8 A Toomey, Royal College of Art, UK - Introduction - Infection risks - Infection control - ‘Visible invisibility’ contaminationaware surfaces Conclusion - References

357

Textile medical produ- for the stabilizationof the thoracic wall E Alexandra and M Carmen, The National htitutefor Textile and Leather, Romania and N Alexandru, VictorBabes Medical and Pharmaceutical University,Romania - Introduction - Experimental - Clinical experiments - Results - Conclusions - References

368

Predicting the fatigue performance of endovascular prostheses H Zhao, L Wang,Y Li andXLiu, Donghua University, China and M W King, North Carolina State University, USA Introduction - Experimental - Results and discussion - Conclusions - References

374

-

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xiii

Integrationand embedding of vital signa 8emom and other devices into tatiles

381

M JAbreu, H Carvalho,A Catarino and A Rocha, Universidade do Mnho, Portugal

-

Introduction

- Review of the state of the art

-

Overview of general principles Experimental,results and discussions Conclusions References

PART MMEDICAL DEVICES Textilebased medical devices: an overview J F Kennedy and C J Knill, ChembiotechLaboratories - Institute of Advanced Science and Technology, UK - What is a medical device? - Medical textiles and their applications - Biomaterials used in medical textiles - References

Design and release rates of a novel biodegradable slow-release implant for the prevention of paediatric dental caries G J Dunn and A F Fotheringham, Heriot-Watt University, UK

-

Introduction

-

Results and discussion

-

References

391

396

- Materials and methods - Conclusions Maternity support garment for the relief of lower back pain S Ho, W Yu,T Lao, D Chow, J Chung and Y Li, The Hong Kong Polytechnic University, Hong Kong - Introduction - Studyaims Study objectives

-

404

summary References

Self-powered medical devicea for vibration suppression

415

L MSwallow, E Sores, D Dodcis and J K Luo, University of Bolton, UK

-

-

Introduction Piezoelectric materials Power harvesting Vibration suppression Device overview

-

Discussion

-

References

-

- Results - Futurework

xiv


Gas plasma treatment of polypropylene (PP) dental tape J M Warren,R R Mather and D Robson, Heriot-Wan University UK and A Neville, University of Lee&, UK - Introduction - Experimental - Surfme characteristics of plasma treated tape - PP tapes as dental flosses - References

423

Investigatingh e t a r e mechanisms of some non-absorbable sutures in Viva A S Hockenberger and E Karaca, Ul&g Universily, Turkey - Introduction Experimental - Results and discussion - Conclusion - References

430

-

Wearable microwave radiometry device for early detection of sub-tissue oncological imperfections T Shah and E Siores, University of Bolton, UK - Introduction - Main types of breast cancer - Detection of breast cancer - Microwave radiometry - Microwave radiometer design and testing - Device integration with fabric - Conclusions - References Investigation of differences in Caprosyn, Biosyn, Polysorb, Novafil and surgipm sutures A D Erem and E Onder, Istanbul Technical University, Turkey and H H Erem, GATA Hayhrpasa Training Hospital, Turkey - Introduction - Materials - Method - Results Conclusions - References

437

449

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PART W SMART MATERIALS AND TECHNOLOGIES

Smart materials and technologies: an overview MMiraBab, University of Bolton, UK - Introduction Review of papers on smart materials - References

-


xv

459

Smart testilea embedded with optical fibre sensors for health monitoring

of patienta F Pirotte, Centexbel, Belgium, A Depre, Elasta, Belgium, R Shishoo, Shishoo Consulting, Sweden, J De Jonckheere, ITM France and A Grillet, Multitel, Belgium - Introduction - OFSETH research project - Preliminary results - Conclusions - References Integrating contactlesssensors for stress level monitoringinto clothing using conductive threads C Rotsch, D Zschena'erlein and U Mohring, TlTv Greiz, Germany - Introduction - Conductivethread materials for the integrationof textile senson and actuators - References Desiguing compressive stmtch garments for improved comfort and fit P A Watkins,London College of Fashion, UK - Introduction - Garment pressure research literature - Traditional pattern design and mobility - Proximal fit pattern design - summary - References

Blun hazard potential, pre-ignition and post-ignition thermal properties of textiles A W Kolhatkar, J D Instifute of Engineering and Technology, India and P C Patel, M S University of Baroda, India

-

Introduction

-

Results and discussion conclusions References

463

472

477

491

- Materials and methods

Assessing the performance of alternating pressure ah mattresses (APAMa) S V S Rithalia and G H Heath, University of Salfrd, UK

-

499

Introduction Methods and materials Results Discussion References

Smart textiles with slow-release ceramides for sensitive skin M Marti, R Ramirez and L Coderch, IIQAB (CSIC), Spain and M Lis, J A Navarro and J Valldeperas,NTEXTER (UPC), Spain Introduction - Ceramides fiom wool - Liposome formation and evaluation

509

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xvi


-

Application of IWL-ceramideliposomes

-

Conclusions

- Microencapsulation - References PART Mn INDUSTRY STANDARJJS AND REGULATIONS Directives,regnlatio~and standardsfor the medical device industry: an overview C J Knill and J F Kennedy, Chembiotech Laboratories - Institute of Advanced Science and Technology, UK - Medical devices in the EU - Medicines and Healthcare Products Regulatory Agency - CEmarking - Safety/quality standard monitoring - Biocompatibilitytesting - TheDrugTariff - References

519

Recent changm to the UK Drug Tariff for appliances listed in Part M G J Collyer, Sumed International Ltd UK - Introduction - History to the reimbursement of appliances - The Gershon Review 2004 - The Supply Cbain Excellence Programme - Conclusions - References

523


xvii

WOODHEAD PUBLISHING SERIES IN TEXTILES 1

Watson's textile design and cololv Seventh edition Edited by Z. Grosicki

2

Watson's advanced textile design Edited by Z. Grosicki

3

Weaving Second edition P. R Lord and M, H. Mohamed

4

Handbook of textile fibres Vol 1: Natural fibres J. Gordon Cook

5

Handbook of textile fibres Vol2: Man-made fibres .l Gordon Cook

6

Recycling textile and plastic waste Edited by A. R. Horroch

7

New fibers Second edition T.Hongu and G. 0.Phillips

8

Atlas of fibre fracture and damage to textiles Second edition J. W.S. Hearle, B. Lomas and W.D.Cook

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Eatextile '98 Edited by A. R Horrocks

10

Physical testing of textiles B. P. Saville

11

Geometic symmetry in patterns and tiling C. E. Horne

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Handbook of technical t e d e s Edited Ly A. R Horroch and S. C. Anand

13

Textiles in automotive engineering W.Fung andJ. M Hardcastle

14

Handbook of textile design J. Wilson

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High-performance fibres Edited by J. W. S.Hearle

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Knitting technology Third edition D. J. Spencer

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Medical textiles Edited by S. C. Anand 0 Woodhead Publishing Limited, 2010

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Regenerated c e l l d ~ fibres Edited by C. Woodings

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S i mohair,cashmere and other luxury fibres Edited by R R Franck

20

Smart fibres, fabrica and clothing Edited by X M Tao

21

Yarn texturing technology J. W. S. HearIe, L. HoIlickandD. K Wilson

22

Encyclopedia of textile finishing H-K Rouette

23

Coated and laminated textilea

K Fung

24

Fancy yams R H. GongandR M. Wright

25

Wool: Science and technology Edited by W.S. Simpson and G. Crawshaw

26

Dictionary of textilefinishing H-K Rouene

27

Environmental impact of textiles

K Slater 28

Handbook of yarn production P.R Lord

29

Textile processingwith enzymes Edited by A. Cavaco-Paul0and G. Gilbitz

30

The China and Hong Kong denim hdllstrp Y. Li, L. Yao and K W.Yeung

31

The World Trade Organhtion and international denim -ding Y. t i , Y. Shen, L. Yao and E. Newton

32

Chemical finishing of textilea W. D.Schindler andP. J. Hauser

33

Clothing appearance and fit J. Fan, W.Yu and L. Hunter

34

Handbook of fibre rope teebnology H. A. McKerma, J. W. S.Hearle andN O'Hear

xx


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Structure and mechanics of woven fabrics J. Hu

36

Synthetic fibres: nylon, polyester, acrylk, polyolebin Edited by J. E. M c l n p e

37

Woollen and worsted woven fabric design E. G. Gilligan

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39

Bast and other plant fibres R R Franck

40

Chemical teating of textiles Edited by Q. Fan

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Design and manniactnre of textile composites Edited by A. C. Long

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Effect of mechankd and physical properties on fabric hand Edited by Hassm M BeheFy

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New millennium 5bem

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Textilea for protection Edited by R A. Scott

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Textilea in sport Edited by R Shishao

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Wearable eleetroaieSand photonics Edited byX M Tao

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Biodegradable and eustainablefibres Edited by R S. Rlackburn

48

Medical textiles and biomateriab for healthcam Edited by S.C. Anand, M M r a a b , S. Rajendrm and J. F. Kenne4

49

Total colonr management in textilea Edited by J. Xin

50

Recyclingin textiles

Edited by Y. Wang

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Clothing biosensory engineering Y. Li andA. S. K Wong

52

Biomechanicalengineering of textilea and clothing Edited by Y. Li and D. X-Q.Dai 0 Woodhead Publishing Limited, 2010

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DigiCal printing of textiles Edited by H. Ujiie

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Intelligent textilea and clothing Edited by H . R Mattla

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Innovation and technology of women's intimate apparel H Yu,J. Fan, S. C. Harlock and S. P. Ng

56

Them d and moisture transport in fibmu materiala Wited by h? Pan and P. Gibson

57

Geosynthetica in eivil engineering

Edited by R K Sarsby

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Handbook of nonwovens Wited by S. Russell

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Cotton: Science and technology Edited by S. Gordon and Y-L. Hsieh

60

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Composite forming technologies Edited by A. C. Long

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Smart textilea for medicime and healthcare Edited by L. Van hgenhove

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Shape memory polymers and textilea J. Hu

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Environmental aspects of textile dyeing Edited by R Christie

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Nanofibers and nanotechnology in a e s mited by P. Brown and X Stevens

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Physical properties of textile fibres Fourth edition W.E. Morton dJ. K S. Hemle

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Advancea in fire retardant materials Edited by A. R Horrocb and D. Price xxii 0 Woodhead Publishing Limited, 2010

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Advancea in wool technology Edited by N. A. G. Johnson and I. Russell

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Militarytextilea Edited by E. Wilurz

74

3D fibrous arsemblies: Properties,appbatiom and modedimensional textile stn~cturea J. Hu

75

Medical and bePlthcare textiles Edited by S.C. Anand, J. F. Kenne&, M Mirajtab andS. Rajendran

76

Fabric testing Edited by J. Hu

77

Biologically inspired textiles Edited by A. Abbott and M EiIison

78

Friction in tertile materials Edited by B. S. Gupta

79

Textile advancea in the automotive industry Edited by R Shishoo

80

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81

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Polyolefin fibres: Indostrial and medical applications Edited by S. C. 0. Ugbolue

83

Smart clothes and wearable technology Edited by J. McCann and D. Bryson

84

Identification of textile fibres Edited by IUHouck

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Advanced textiles for wound care Edited by S. Rajehan

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Fatigue failure of textile fibres Edited by M MU-a#ab

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Advancea in carpet technology Edited by K Goswami

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Handbook of textile fibre strnctnre Volume 1and Volume 2 Edited by S. J. Eichhom, J. W. S. Hearie, M J@e and T. Kikutani 0 Woodhead Publishing Limited, 2010 xxiii

of three-

89

Advancea in knittingtechnology Edited by K-F. Au

90

Smart textile coatings and laminated Edited by K C. Smith

91

Handbook of tensile propertied of textile and teehnid fibres EdiredbyA. R Bunsell

92

Interior textilea: Design and developmentu Edited by T. Rowe

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Textiles for cold weather apparel Edited by J. T.Williams

94

Modelling and plpdicthg textile behavionr Edited b y X Chen

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Textilea, plymere and compOaitca for baildings Edited by G. POW

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Engineering apparel labrice and garments J. Fan and L. Hunter

97

Surface modification of textilea Edited by Q. Wei

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Sustainable textilea Edited by R S. Blackhm

99

Advancea in textile fibre ~piMingteebnology Edited by C. A. h e n c e

100 Handbook of medical textilea Edited by Y. T.Bartels 101 Technical textile yarna Edited by R Alagirusamy and A. Das 102 Applications of nonwovem in technical textilea Edited by R A. Chapman 103 Colour measurement: Principles, advancee and industrial applicdom Edited by M L. Gulrqjani

104 Textiles for civil engh?erhg Edited by R Fangwiro 105 New product development in textilea Edited by B. Mills 106 Improving comfort in clothing

Edited by G. Song

xxiv 0 Woodhead Publishing Limited, 2010

107 Advances in textile biotechnology Edited by V. A. Nierstrasz and A. Cavaco-Pado 108 Textiles for hygiene and infection control

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Edited by Y. Li 110 Joining textiles: principles and applrcations Edited by 1 Jones and G. StyIios 11 1 Soft computing in textile engineering

Edited by A, Mqumdar 112 Textiledesign Edited by A. Briggs-Goode and X Townsend 113 Biotertilea as medical implanta

Edited by IUKing and B. Gupta 114 Textile thermal bioengineering Edited by Y. Li

115 Woven textile structure B. X Behera and P. K. Hmi 116 Handbook of textile and industrial dyeing. Volume 1: principles processes and

types of dyes Edited by M Clark 117 Handbook of textile and industrial dyeing. Volume 2: Applications of dyes

Edited by M CIark 118 Handbook of natural fib-.

Volume 1: Typea, properties and factors affecting

breeding and cultivation Edited by R Kozlowski 1 19 Handbook of natural fibres. Volume 2: Processing and applications Edited by R Kozlowski

120 Functional textiles for improved performance, protection and health

Edited by N.Pan and G.Sun 121 Computer technology for textiles and apparel

Edited by Jmlian Hu 122 Advances in military textilea and personal equipment Edited by E. Sparks 123 Specialist yarn, woven and fabric structure: Developmenta and applications Edited by R H Gong

0 Woodhead Publishing Limited, 201 0 xxv

Healthcare and medical textiles play a significant role within the technical textiles sector. The increased awareness of the need to enhance the quality of life of people has significantly contributed to the high consumption and sustained growth of medical textiles over the past decade. The importance of medical textiles is reflected in the fact that it already accounts for over 10% of the technical textiles market. It is interesting to note that the consumption of medical textiles in countries like India and China has grown remarkably in the recent past and is expected to grow significantly in Africa and Middle East in the next decade. There is a considerable market potential for advanced wound dressings with a forecast annual growth of between 10% and 15% in 2012. A number of medical textiles products that include wound dressings and bandages are now classified as ‘medical devices’ by European legislation with the need to carry CE marking. This indicates their importance and the fact that they occupy a unique position within medicine and surgery. As an example, compression therapy using compression bandages is considered as the ‘gold standard’ for managing venous ulceration. Until now there has been no alternative medication or surgical procedure to cure the disease. The University of Bolton has gained worldwide recognition in medical textiles research, product development and knowledge transfer. With regard to knowledge transfer activities, the University is unique in organising international conferences focusing only on healthcare and medical textiles as well as publishing interdisciplinary statesf-the art books exclusively for medical professionals, medical device manufacturers, textile scientists and researchers. The University has so far hosted international MEDTEX conferences in 1996, 1999, 2003 and 2007 at Bolton and joint international conferences (FiberMed) in collaboration with Tampere University of Technology in Finland in 2000 and 2006. In the past books such as Developments in medical textiles, Medical textiles 96: Medical textiles 99 ’, Medical textiles and biomaterials for healthcare and Advanced textiles for wound care, published with Woodhead Publishing Limited,have attracted a great deal of attention from readers. This book, Medical and healthcare textiles, comprises of a selection of papers presented and discussed during MEDTEX 07. There are eight parts to the book, each of them containing an introductory overview. Part I contains fifteen papers and addresses the risk of infection, cross-infection and infection control. The application of textile materials and products to prevent and control infection is extensively discussed. Six papers in Part II demonstrate the significance of textile products in healthcax and hygiene applications for use not only in hospitals but also in other environments where hygiene is essential. Advanced wound dressings such as drug delivery dressings and odour-adsorption dressings are critically discussed in Part 111which also comprises six papers. Part IV is divided into seven papers and highlights multilayer and single-layer compression therapy for venous leg ulcer patients. Recent developments and application of hi-tech implantable medical devices are discussed in the seven papers which constitute Part V. Part VI consists of seven papers which emphasise the role of textiles in medical devices in various applications including dentistry and oncology. The integration of novel sensors in textile products for the application of wearable health monitoring products and research related to smart materials are discussed in Part VII 0 Woodhead Publishing Limited, 2010 xxvii

which is made up of 6 papers. A special paper in Part WI describes the role of the Drug Tariff regulatory body in the UK as well as the recent chmges affectingthe medical devices market. The editors are deeply indebted to all the authors in this publication. Their contributions are invaluable for the further development of the medical textiles sector around the world. We are grateful to all the companies who sponsored and supported MEDTEX 07. The assistance provided by Mrs Anita Taylor during the preparation of the book is gratefully acknowledged. Last, but not the least, we are thankfd to Woodhead Publishing Limited in Cambridge for their continued support over a number of years in publishing specialist books relating to medical textiles. Prof S. C. Anaud MBE DrM.MiraRab Dr S. Rajendran Institute for Materials Research and Innovation The University of Bolton, UK

Prof J. F. Kennedy Chembiotech Laboratories Institute of Advanced Science and Technology, UK

xxviii 0 Woodhead Publishing Limited, 2010

PART I

INFECTION CONTROL AND BARRIER MATERIALS

INFECTION CONTROL AND BARRIER MATERIALS- AN OVERVIEW S.Rajendran Institute for Materials Research and Innovation University of Bolton, Bolton BL3 5AB, UK

INTRODUCTION With the arrival of high risk microorganisms such as (Methkillin-resistant stuphyiococcus uureus) MRSA and Swine flue (HlN1 virus), infection control is a serious problem, especially in hospital environments. Hospital-acquired infections cost the National Health Service (NHS) in the UK E l billion and contribute to the death of an estimated 5000 patients a year. The Department of Health in the UK estimates that such infections can cost an extra fA000d10000 per patient. Controlling wound infixtion in hospitals is a day-to-day problem for healthcare personnel despite the precautionary measures taken to avoid them. Both acute and chronic wounds are vulnerable to bacterial infection. Highly-exudating wounds, macerated and slough wounds are often at risk of infection. About 8% of hospital in-patients in England develop infections and in intensive care units the figure raises to 23%.

In order to address the problem with particular reference to MRSA and Clostridium diflcile, a new E4.2 million consortium has been jointly created by the Biotechnology and Biological Sciences Research Council (BBSRC), the Medical Research Council (MRC), the National Institute for Health Research (NIHR) and the Welcome Trust in the UK. The projects the consortium plans to fund will range fiom organising a rapid response, springing into action if a particularly virulent strain of MRSA emerges and analysing its particular signature so it can be quickly detected and controlled, to finding the best ways to change the habits of hospital staff, patients and visitors to prevent infections from occurring and spreadiig. The consortium will look at issues such as quick detection and control of the spread of virulent strains of MRSA, the mode of spreading to hospital equipments such as latex gloves, and identify the best strategies for preventing the spread of infection. WOUND INFECTION Wound management that includes chronic wounds such as pressure sores, venous leg ulcers is one of the crucial areas which needed to be addressed for elderly and immobile communitiesbecause ageing and immobility weaken the intact of the skin that provide a physical barrier to the ingress of microorganisms. The skin is an important defence layer of the body as it protects fiom microorganisms, UV radiations and injury. It maintains the temperature of the body besides helping the body to gain vitamin D fiom sunlight. Wounds are formed when the skin is broken, and the healing process depends on the extent of damage to the epidermis, dermis and subcutaneous layers of the skin. Superficial wounds only damage the epidennis but the partial thickness and fullthickness wounds respectively damage the dermis and subcutaneous fatty tissues and/or bone. Wound healing by primary intention refers to the skin edges that have been brought together by sutures, and surgical adhesives. On the other hand, the secondary intention describes wound healing when the skin edges are not brought together and have to heal by contracting and filling up with granulating tissues. Wounds such as leg 0 Woodhead Publishing Limited, 201 0

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ulcers and pressure ulcers fall in this category, and they are chronic because it takes a longer time to heal. The skin in children and healthy adults is strong and inhospitable to pathogenic microorganisms but weak for elderly population and those confined to wheelchair. Once the line of defence is broken there is a risk of infection. Ageing decreases the eEciency of wound healing mechanisms. Once wound is formed replacement of epidermal cells, inflammatory response, sensory perception and barrier function decrease through the ageing process. Arterial and venous disease can delay wound healing, and are a common problem to the elderly population. The ultimate aim of wound management is to promote healing without microbial infection. Infection in the wound results in an increased production of exudate and delayed wound healing. Wounds in elderly people do, however, heal with good effect with carem management by selecting appropriate dressings. Wound dressings vary with the type of wound and management technique and no single dressing is universally applicable for healing all types of wounds. An ideal dressing is normally expected to provide barrier against dirt and other foreign bodies, provide humid environment at the wound surface that enhances wound healing, control exudate and be removed without trauma. The dressing should provide a barrier against pathogenic bacteria including the challenging MRSA (methicilh-resistant staphylococcus aureus) and MRSSA (Methicillin susceptible Staphylococcus aureus) bugs because cross-infection by bacteria through wound dressings and hospital textiles is increasingly common in hospitals and has been a major problem over several years. In the UK alone only a small number of patients (104) were infected by MRSA in 1992 but this figure rose to 4,904 in 2001. According to Office for National Statistics, the number of death in England and Wales involvingStaphylococcus aureus increased from 1,212 in 2001 to 2,083 in 2005. The death rate increased by 69% due to Clostridium dzJicile. Elderly people are vulnerable to risk as evidenced that the death rate in 2007 involving 85 and over age groups represents 767. It must be pointed out that certain bacteria, for example MRSA super bug shows resistance even to antibiotics. The bug is contagious and transmitted through skin contact as well as hospital textiles in hospital environment. It should be noted that the currently available wound dressings are effective against only a few types of bacteria and no such dressings provide a complete shield against a wide spectrum of pathogenic bacteria that include MRSA and MRSSA. In a broad sense, an ideal wound dressing should fulfil many major requirements which include high barrier properties against a broad spectrum of pathogenic microorganisms. HOSPITAL PROTECTIVEMATERIALS

Infection and cross-infection are nowadays more common in hospitals where the prevalence of microorganisms is high. Microorganisms are broadly classified as bacteria, fungi and viruses. Gram-positive bacteria include Staphylococcus aureus, Staphylococcus epidermidis, MASA and MRSSA and Gram-negative bacteria comprises of Proteus vulgaris, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Fungi (Candida albicons, Aspergillus niger), bird flue and swine flue are typical examples of viruses. Gram invented a staining method in 1884 to distinguish the bacteria based on colour changes. Gram-positive bacteria are purple and --negative bacteria are red after Gram staining. The bacteria cause infections such as superficial infections, acute gastro-enteritis, infections of wound, burn, respiratory and urinary tract. Infwtions associated with f h g i are: ear, nose and lung infections; 4


tinea nigra of palms; white pildra of bear4 diaper rash athlete’s foot; ring worm; and tinea, pulmowy, mucosa and hair infections. It is known that textiles carry and transmit infections fiom one person to another through clothing, bedding and related textile products used in hospitals and other potentially risk environments, and laundering process do not remove the risk of infection. Therefore it is vital that textile materials with antimicrobial properties are developed by using the following principal techniques: 0 0 0

0 0

Imbuing antibacterial agents into the fibres or depositing onto the fibres. Chemical modification of fibres by formation of covalent bonds. Coating on the surface of fabrics. Microencapsulationof antibacterial agents. Plasma treatments.

It is also crucial that the developed materials should possess antimicrobial activity against a wide range of microorganisms that include super bugs such as MRSA. Antimicrobial textiles can be either active or passive materials. It will be noted that the passive materials do not contain active substances but their surface structure (Lotus effect) produces a negative effect on the living conditions of microorganisms (antiadverse effect). Textile materials that contain active antimicrobial substances act upon either in or on the bacterilal cell. There are several antimicrobial agents such as quaternary ammonium compounds, antibiotics, iodophors, phenols, ureas, organosilicons and silver containing agents and they are mostly act upon either the bacterial cell during the metabolism or within the genome. For example, Triclosan (polychloro phenoxy phenol) inhibits the growth of microorganisms by using an electro-chemical mode of action to penetrate and disrupt their cell walls. When the cell walls are penetrated, leakage of metabolites occurs and other cell functions are disabled thereby preventing the organism fiom functioning or reproducing. Silver has been known to possess antimicrobial characteristics since ancient times. Silver and nanosilver containing antimicrobial agents, for instance sodium silver sulphadiazine- SSD, are widely used both in hospital textiles and wound dressings because silver is generally recognised as a safe and broad-spectrum antimicrobial agent. Silver acts as a heavy metal by imparting the bacterial electron transport system and some DNA function. In addition to the above synthetic antimicrobial agents, the natural product antimicrobial agents such as chitosan, aloe Vera, tea tree oil, eucalyptus oil, tulsi extracts, neem and a number of medicinal plants have been systematicallyexamined for potential use as effective antimicrobial agents in hospital textiles and wound dressings. The major advantages of using natuml antimicrobial agents over synthetic antimicrobials include lower incidence of adverse reactions and eco-friendliness. It should be mentioned that neem (Azadirachta indica) and tulsi (Ocimum basilicum) possess a rich source of antimicrobial compounds and are abundantly found in the Indian subcontinent. Recent studies have demonstrated the use of neem seed and bark extracts on cellulosic substrates to impart antibacterial activity against both Grampositive and Gram-negative bacteria. It is a well established fact that honey possesses broad spectrum of antimicrobial activity and has a long history of medical use. The high sugar content and the ability to produce hydrogen peroxide make the honey antimicrobial. There is increasing interest nowadays in using honey in wound management. Medical grade honey particularly Manuka honey has been successfully 0 Woodhead Publishing Limited, 2010

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used in a wide range of wound dressings for managing superficial wounds, sinus wounds, cavity wounds, burn wounds and the treatment of diabetic foot ulcers. BIBLIOGRAPHY 1 K Bertal, J Shepherd, C W I Douglas, J Madsen, A Morse, S Edmondson, S P Arms, A Lewis and S MacNeil, ‘Antimicrobial activity of novel biocompatible wound dressings based on triblock copolymer hydrogels, J Material Science, 2009 44(23) 6233-6246.

2 S H Lim and S M Hudson, ‘Reviewof chitosan and its derivative as antimicrobial agent and their uses as textile chemicals’, JMacromolecular Science, Polymer Reviews 2003 C43 223-269. 3 B S Atiyen, M Costagliola, S N Hayek and S A Dibo, ‘Effect of silver on burn wound infection control and healii: Review of the literature’, Korean J Dermatology, 2008 46(12) 1595 - 1602. 4 M Joshi, S W Ali, R Purwar and S Rajendran, ‘Ecotkiendly antimicrobial finishing of textiles using bioactive agents based on natural products, Zndian J Fibre & Text Res, 2009 34 295-304. 5 M Joshi, S W Ali and S Rajendran, ‘Antibacterialfinishing of polyestedcotton blend fabrics using neem (azadirachta indica): A natural bioactive agent’, J Applied Polymer Science, 2007 106 793-800.

6 NHSSB Wound Management Manual, Northern health and Social Services Board, 2005,4142.

7 National Prescribing Centre, ‘Modem wound dressing management’, Pres Nurse Bullt, 1999 l(2) 8. 8 C Basualdo, V Sgroy, M S Finola and J M Marioli, ‘Comparison of the antimicrobial activity of honey fiom different provenance against bacteria usually isolated fiom skin wounds’, Vet Microbial, 2007 124 375-381.

9 P C Mohan, ‘The role of honey in wound management’, J Wound Care, 1999 8(8) 415-418. 10 J Betts, ‘Guidelines for the clinical use of honey in wound care’, In: R Cooper, P Molan and R White, Honey in Modem Wound Management, HealthComm UK Ltd, Aberdeen, 2009.

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ANTIMICROBIAL PROPERTIES OF SILVER-CONTAINING CEUTOSAN FIBERS Yimin Qin and Changjun Zhu The Biochemical Materials Research and Development Center, Jiaxing College, 56 Yuexiu Road South, J i m 314001, Zhejiang Province, China. Email: [email protected] ABSTRACT

In order to prepare antimicrobial silver containing chitosan fibers, silver sodium hydrogen zirconium phosphate with particle diameter < lum were mixed with the chitosan solution and made into fibers by the wet-spinning process. When in contact with solutions containing protein and metal ions, silver ions can be released from these fibers through chelation and ion exchange. This paper discussed the antimicrobial effect of chitosan fibers and silver containing chitosan fibers against three common types of bacteria, i.e., Candida albicans, Staphylococcus aureus and Pseudomonas pyocyanea. Results showed that the silver containing chitosan fibers have much stronger antimicrobial effect than the chitosan fibers.

Key words: chitosan fiber; silver containing chitosan fiber; antimicrobial property INTRODUCI’ION Silver has a long history as an antimicrobial agent[’-’], especially in the treatment of bums. While metallic silver is relatively inactive, silver ions are effective against a wide range of bacteria. When low concentrations of silver ions accumulate inside cells, they can bind to negatively charged components in proteins and nucleic acids, thereby effecting structural changes in bacterial cell walls, membranes and nucleic acids that affect viability[”81. In addition, although silver is a highly effective antimicrobial agent, it has a limited toxicity to mammalian cellsrg1. It was found that the use of silver containing wound dressings can increase the rate of epithelialisationby 28%, indicating a beneficial effect of silver ions to skin regeneration, in addition to its antimicrobial activity. In recent years, silver has been gaining importance as an effective antimicrobial agent that does not result in bacteria resistance. Silver containing antimicrobial products have been developed so that a low concentration of silver ions can be released over time. A number of laboratory studies have shown the excellent antimicrobial performances of the silver containing antimicrobial products[23 ‘I. This paper presents the results of a study on the antimicrobial properties of silver containing chitosan fibers.

EXPERIMENTAL A spinning dope was prepared by dissolving 3 kg of chitosan powder in 97kg of 1% aqueous acetic acid solution. 30 g AlphaSan RC5000 (a silver sodium hydrogen zirconium phosphate containing 3.8% by weight silver) was added into the solution and thoroughly mixed with the chitosan solution. After storage at room temperature for two days to remove the bubbles, fibers were produced by extruding the dope through a spinneret with 4,000 holes (hole diameter 80 um) at 12 d m i n into an aqueous 0 Woodhead Publishing Limited, 201 0

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coagulation bath containing 4% NaOH. The as-spun fibers were taken up at 7.2 d m i n and then stretched at 8OoCto the maximum extent. The fibers were then washed with water and acetone before being dried by hanging in air. Finally, the dry tow was cut to produce 50 mm length staple fibers. When analyzing the silver ion contents in the chitosan fibers, 0.5 g fibers were treated with 7 ml concentrated sulphuric acid until the fibers were fully digested. The mixture was then diluted to 100 ml with distilled water and filtered. The silver ion concentrationwas determined by using atomic absorption spectrometer. When testing the release of silver ions from the fibers, the fiber sample was placed in contact with 40 times its own weight of either distilled water, solution A or aqueous solutions containing different amount of protein. The British Pharmacopeia specified solution A as an aqueous solution containing 142 millimoles of sodium chloride and 2.5 millimoles of calcium chloride, representing the typical ion concentrationsof body fluid. The protein used was water soluble soya bean protein. After conditioning at specified temperatures for different periods of time, 5 ml solution was taken out and tested for silver ion concentrationby using atomic absorption spectrometer. The antimicrobial activity of the fibers was tested against three common strains of bacteria, i.e., Candi& albicans, Staphylococcus aureus and Pseudomom pyocyanea. The bacteria were suspended in 0.5% peptone water with the bacteria concentration at about 1.5x104to 1.5x105c~ml.35 ml0.5% peptone water were measured into looml conical flasks and to each of them were added 2.5ml of the bacteria suspension, with the bacteria concentration in the conical flask controlled at between l x l d and lx104 c W d . After that, 0.375 f0.002g of sterilized silver containing chitosan fibers were added into the conical flasks respectively. The fibers were placed in contact with the bacteria suspension; the conical flasks were placed in a water bath at 36OC and were shaken at a speed of 180 r/min for 8 hrs. 0.1 ml of the bacteria containing solution was then taken out to measure the colony forming units. The reduction in the number of bacteria is calculated in the following equation : Reduction in bacteria = [A-B]/A x 1000? Where : A : The average bacteria concentration in the control sample after shaking , cWml B : The average bacteria concentrationin the test sample after shaking , cWml

RESULTS AND DISCUSSION Figures 1 show the SEM photomicrographs of the silver containing chitosan fibers. It can be seen that although the silver containing chitosan fiber generally has a smooth surface structure, the Alphasan RC5000 particles are visible and can be seen embedded into the chitosan structure. When the fiber is wet with 0.1% aqueous acetic acid solution, it can be seen under optical microscope that the silver containing Alphasan RC5000 particles are fairly uniformly distributed inside the fiber structure, acting as the reservoir for releasing the antimicrobial silver ions.

8


Fig 1: SEM Photomicrographof the silver containing chitosan fiber Figure 2 shows the release of silver ions when the silver containing chitosan fibers were placed in contact with three different solutions at 37 OC. With distilled water, the silver concentration was low and remained at about 0.137 u g / d over extended period of time. In both solution A and 2.9%aqueous protein solution, the silver concentrations in the contacting solutions were much higher than in distilled water. With solution A, the silver concentration slowly rose fiom 0.402 ug/ml at 30 min to about 0.654 ug/ml after 24 hrs. The silver concentration in the 2.9% protein solution was much higher than in solution A. At 4 hrs, the silver concentration in the protein solution was 1.31 ug/ml, about twice those measured in solution A after same period of contact with the silver containing fibers. 1.4 1 1.2

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Fig 3: Effect of temperature on the silver release when the silver containing chitosan fibers were in contact with solution A Figure 3 shows the effect of tempemture on the silver release when the silver containing chitosan fibers were in contact with solution A. After 24 hrs, the silver ion concentration in solution A were 0.370, 0.654 and 0.765 u g h l at 21, 37 and 65°C respectively, with the silver ion concentrationat 65°C roughly double that at 21°C. This shows that the rate of silver ion release can be significantly elevated when temperature is increased. It is possible that at a higher temperature, the fibers can swell more as water penetrates inside the fiber. In addition, the ion exchange process can also be accelerated at an elevated temperature. Figure 4 shows the silver ion concentrations when the silver containing chitosan fibers were in contact with aqueous solutions containing different amount of protein at 37 "C. It is clear that the silver ion concentration in the contacting solution is directly proportional to the protein concentration. The effect of a high protein concentration is fairly obvious, with the silver ion concentration in the 5% protein solution about 4 times that of the 1% protein solution after 30 min.

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Fig 4: Silver ion concentrations when the silver containing chitosan fibers were in contact with aqueous solutions containing different amount of protein at 37 OC The silver ions released from the silver containing chitosan fibers can act as an effective antimicrobial agent. Although chitosan is already well known for its antimicrobial properties, this is mostly due to the positive charge on the amine groups which controls bactetia growth by its ability to combine the negatively charged bacteria cells. Though this action can help limit the bacteria growth, its action is bacteriastatic rather than bactericidal. Table 1 shows the antimicrobial effect of the silver containing chitosan fibers against three common strains of bacteria. It is clear that with all three types of bacteria, the silver containing chitosan fibers are effective in reducing the bacteria count by more than 98%. In Table 2, the antimicrobial effect of chitosan fibers and silver containing chitosan fibers are compared against Candich albicans. Under the same test conditions, the reduction in bacteria count for the chitosan fiber is 78.62%, whilst for the silver containing chitosan fiber, the reduction is 97.22%. This clearly demonstrates that the silver containing chitosan fiber is more effective in controlliig bacteria growth than the chitosan fiber. Table 1. The antimicrobial effect of silver containing chitosan fibers against three common bacteria Type of Bacteria Bacteria Concentration YOReduction in Cfu/ml bacteria count Control Test sample Candida albicans 1 .46x105 2005 98.63 Staphylococcus aureus 1 . 2 1~o4 168 98.60 7.16 x 1O6 1 100 Pseudomom pyocyanea


11

Table 2. The antimicrobial effect of chitosan fibers and silver containing chitosan fibers against Candida albicans Sample Control Chitosan Fiber Ag Chitosan Fiber Bacteria 54x10’ 1155 150 concentration,cWml % Reduction in 78.62 97.22 bacteria count

CONCLUSIONS This study has shown that silver containing chitosan fibers can be made by blending silver containing AlphaSan RC5000 particles in the spinning dope. Experimental results showed that when the silver containing chitosan fibers are placed in contact with either solution A or aqueous protein solution, silver ions can be released from the fiber through ion exchange and chelation. More effective in releasing the silver ions from the fiber takes place with chelation with protein molecules. It has been found that the silver containing chitosan fiber is more effective in controlling bacteria growth than the original chitosan fiber. Acknowledgement

This work was financially supported by the Natural Science Fund of Zhejiang Province, China (Grant No. Y405030). REFERENCES 1 C J Coombs, A T Wan and J P Masterton, ‘Do burns patients have a silver lining’, B u m , 1992 18(3) 179-184. 2 E A Deitch, A A Marino and V Malakanok, ‘Silver nylon cloth: in vitro and in vivo evaluation of antimicrobial activity’, J Trauma, 1987 27(3) 301-304.

3 J R Furr, A D Russell and T D Turner, ‘Antibacterial activity of Actisorb Plus, Actisorb and silver nitrate’, J. Hospital Infection, 1994 27(3) 201-208. 4 A B G Lansdown, B Sampson and P Laupattarakasem, ‘Silver aids healing in the

sterile wound: experimental studies in the laboratory rat’, Brit. J. Dermatol., 1997 137 728-735.

5 A D Russell and W B Hugo, Antimicrobial activity and action of silver, In: Ellis, G. P., and Luscombe, D. K. (eds). Progress in Medicinal Chemistry, Elsevier Science, London, 1994. 6 R C Charley and A T Bull, ‘Bioaccumulation of silver by a multispecies population of bacteria’, Arch. Microbiol., 1979 123 239-244. 7 S M Modak and C L Fox, ‘Binding of silver sulfadiazine to the cellular components of Pseudomonas aeruginosa’, Biochemical Pharmacology, 1973 22( 19) 2391 -2404. 12


8 T N Wells, P Scully and G Paravicini, ‘Mechanisms of irreversible inactivation of phosphomannose isomerases by silver ions and flamazine’, Biochemishy, 1995 34 7896-7903.

9 M A Hollinger, ‘Toxicological aspects of silver pharmaceuticals’, Crit. Rev. Toxicol., 1996 26 255-260.


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COPPER-IMPREGNATEDANTIMICROBIAL TEXTILES; AN INNOVATIVE WEAPON TO FIGHT INFECTION Gadi Borkow, Anthony Felix and Jeffrey Gabbay Cupron Inc, Greensboro, USA

ABSTRACT A platform technology has been developed in which coppr oxide is impregnated or plated into polymeric fibres or cotton fibres, respectively, endowing the fibres with potent broad-spectrum anti-bacterial, anti-viral, anti-fungal and anti-mite properties [11. This durable platform technology introduces copper oxide-treated fibres and enables the mass production of woven and non-woven fabrics with no requirement for alteration of industrial procedures or machinery. This technology facilitates the production of autiviral gloves and filters (which deactivate HIV-1and other viruses); anti-bacterial selfsterilizing fabrics (which kill antibiotic resistant bacteria, including MRSA and VRE); anti-fungal socks (which alleviate symptoms of athlete's foot); anti-dust mite mattresscovers (which reduce mite-related allergies) and gauze (which is highly effective in promoting skin regeneration, closure of chronic wounds and the alleviation of bed sores). This paper will demonstrate the potential use of copper in new applicationsthat address medical issues of the greatest importance such as viral transmissions; nosocomial infections; wound healing and the spread of antibiotic resistant bacteria

COPPER AS A BIOCIDE Copper ions have been used for centuries to disinfect fluids,solids and tissues [2,3]. The ancient Greeks (400 BC) prescribed copper for pulmonary diseases and for purifying drinking water. The Celts produced whisky in copper vessels in Scotland around 800 AD, a practice that has continued to the present day. Copper strips were nailed to ship's hulls by the early Phoenicians to inhibit fouling, as cleaner vessels were faster and more manoeuvrable. Gangajal (holy water taken from the Ganges River) has been stored in copper utensils in Hindu households for centuries due to copper's anti-fouling and bacteriostatic properties. By the 18' century,copper had come into wide clinical use in the western world for the treatment of mental disorders and afflictions of the lungs. Early American pioneers moving west across the continent put silver and copper coins in large wooden water casks to provide them with safe drinking water for their long voyage. In World War II, Japanese soldiers put pieces of copper in their water bottles to help prevent dysentery. Copper sulphate is highly prized by some inhabitants of Africa and Asia for h e a l i i sores and skin diseases. NASA first designed an ionization coppersilver sterilizing system for its Apollo fights. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide, and as an anti-bacterial and anti-fouling agent [4-81. It is considered safe to humans, as demonstrated by the widespread and prolonged use of copper intrauterine devices (IUDs) by women 19-11]. In contrast to the low sensitivity of human tissue (skin or other) to copper [12], micro-orgauisms are extremely susceptible to copper. Copper toxicity to micro-organisms, including toxicity to viruses, may occur through the displacement of essential metals from their native binding sites, from interference with oxidative phosphorylation and osmotic balance and from alterations in the conformationalstructure of nucleic acids, membranes and proteins [131. 14


- polyester fibrescontaining3% (w/w) copper oxide particles (right panel). INCORPORATION OF COPPER OXIDE INTO NATURAL AND SYNTHETIC FIBERS U t i l i i g the properties of copper, two durable plafform technologies were developed [1,13]: the first one plates cotton fibres with copper oxide (Fig 1, left panel) and the second one impregnates polyester, polypropylene, polyethylene, polyurethane, polyolefin or nylon fibres with copper oxide (Fig 1, right panel). The fibres can be cut into short staple or produced in filament form and texturized, if so desired. The product yielded is a fibre that can be introduced at the blending stage of yarn production or directly into a woven or knit product so that no manufacturing processes are changed. Woven and non-woven fabrics can be produced.

BIOCIDAL PROPERTIES OF FABRICS CONTAINING COPPER OXIDE Antibacterial Exposure of gram positive or gram negative bacteria to fabrics containing copper oxide particles results in potent reduction in their viable titres (Table 1). Table 1: Antimicrobial properties of wpper-oxide impregnated fabrics

Type of Copper % of Copper Treated Fibres in Fabric (w/w) Plated Cellulose 0.2 0.2 0.2

0.2 Polyester

1 1 1

Polypropylene

3 3 3 3 0.5 0.5

1

Nylon

Name of Time (hr) % Reduction Orpanism Tested of E x D o ~ ~ r eof Titre Staphylococcusaureus 1 >99.8 MRSA 1 >99.5 VRE 1 99.5 Escherichia coli 1 >99.9 4 >99.9 Staphylococcusaureus Listeria 1 >99.8 Salmonella 2 >98.5 Escherichia coli 1 >99.9 Staphylococcus aureus 3 >99.9 Escherichia coli 3 >99.9 Klebsiella pneumoniae 3 >99.9 Enterococcus 3 >99.9 Staphylococcusaureus 2 >99.9 Escherichia coli 1 >99.9


15

Exposure of fungi to fabrics containing copper oxide particles results in potent reduction in their viable titres (Table 2). Table 2: Antifungal properties of copper-oxide impregnated fabrics Name of Time (hr) % Reduction Type of Copper % of Copper Orrranism Tested of Ex~osure of Titer Treated Fibres in Fabric (w/w) Plated Cellulose 0.2 Candida albicans 24 >99.9 Candida albicans 24 >99.9 Polyester 0.5 1 Tricophyton mentagrophytes 24 >99.9 1 Tricophyton rubrum 24 >99.9 1 Aspergillus niger 24 >%.9 3 Candida albicans 24 >99.9 Polypropylene 24 >99.9 Nylon 0.5 Candida albicans The American Association of Textile Chemists and Colorists (AATCC) Test Method 100-1993 was used to determine the biocidal properties of the fabrics against the bacteria and h g i tested. The initial bacterial or fungal inoculum used varied between lx105 to 4x106 colony forming units (cfu)/sample. These tests were carried out by independent laboratories: AminoLab Laboratory Services, Weizmaun Industrial Park, Nes Ziona 79400, Israel, and Hy Laboratories Ltd., Park Tamar, Rehovot 76325, Israel.

Antiviral Filters containing copper oxide-impregnated polypropylene fibres can reduce infectious titres of a panel of viruses spiked into culture media (Table 3). Enveloped; non-

enveloped; RNA and DNA viruses were affected, suggesting the possibility of using copper oxide-containing devices to deactivate a wide spectrum of infectious viruses found in filterable suspensions. Prolongation of the exposure of these micro-organisms to the copper oxide-containing fibres further reduced their viable titers. Table 3. Reduction of infectiousviral titers by copper-oxide containing filters % InfectivitvReduction HN-1 >99.99 Punta Tor0 >99.99 99.99 Rhinovirus2 99.99 Pichinde 99.95 CMV 99.95 Measles 99.5 Influenza A WNV 99.5 99 AdenovirUs 99 RSV 96 Paraintluenza3 95 Yellow Fever 94 VEE Vaccinia 80 16


The CMV testing was done at the Ben Gurion University, Beer Sheva, Israel by Dr. Shemer-Avni; HIV-1 and Adenovirus testing was done in Cupron Biosafety Viral Laboratory, Rehovot, Israel. All other viruses were tested at the Institute for Antiviral Research, Utah State University, Utah, USA. Anti-mite efficacy

Figure 2 shows the result of an experiment in which the effect of two fabrics, one containing 0.4% and one containing 2% copper oxide (w/w), were tested for anti-mite activity. The house dust mite tested was Dermatophagoiaks fwinae. While during the first 12 days of the experiment all mites exposed to control fabrics were alive, more than 60% and 100% of the mites exposed to the 2% copper fabric were dead afier 1 and 5 days, respectively. Approximately 50% of the mites exposed to the 0.4% copper fabrics died within 12 days of exposure to the fabrics. After 47 days of culture, 86% and 67% of the mites in the absence of any fabric and in the control fabric containers were alive, while all mites exposed to the 0.4% copper fabric were dead. This and other experiments with mites were conducted under a subcontract agreement by Dr. Kosta Y. Mumcuoglu fiom the Department of Parasitology, Hebrew University-HadassahMedical School, Jerusalem 91 120, Israel.

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CLINICAL STUDIES Athlete’s foot efficacy Fifty six individuals s e e r i n g fkom athlete’s foot (tineu pedis) were given socks containing 1% copper-oxide in the soles of the socks. The individuals were asked to wear the copper-socks on a daily basis. During this period the individuals did not receive any local or systemic anti-fungal treatment and their feet were monitored by a podiatrist. The following measures were studied: erythema, buming and itching, oedema, scaling, vesicular eruptions and fissuring. In all attributes there was a significant improvement or resolution of the attributes studied in an average follow up of 9 days (Fit3 3).


17

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Healing of diabetic ulcers Copper is a key player in many of the complicated processes that together comprise the wound repair mechanism. For example, copper stimulates the formation of new capillaries in the skin via induction of vascular endothelial growth factor (VEGF), copper stabilizes fibrinogen [14,15] and collagen and copper modulates inkgrins expressed during the final healing phase [1 61. Thus, taking together the potent biocidal activities of copper [131, the very low risk of adverse skin reactions associated with copper [12,17],and its roles in the wound healing process, strongly support the notion that the addition or application of copper or copper containing products, such as band aids and gauze containing copper, to wounds may significantly enhance the wound healing process. Indeed, in preliminary data demonstrate that treating chronic diabetic ulcers, which failed or responded poorly to conventional treatments, with copper oxide containing pads, results in significant closure and resolution of the chronic ulcers. One such example is shown in Figure 4.

Figure 4. Healing of a chronic ulcer in the foot of a 71 years old diabetic patient. The wound did not close even when treated for 9 months by conventional treatment (oral antibiotics, Acticoat Absorbent, Allevyn, Apligraf and sharp debridement).

18 0 Woodhead Publishing Limited, 2010

DISCUSSION Permanent or durable binding of inorganic compounds to organic substrates is extremely difficult, especially for mass production processes. By utilizing the properties of copper, two inexpensive platform technologies were developed which permanently bind copper to textile fibres from which woven and nonwoven fabrics can be produced. The introduction of copper oxide at the early stages of the production cycle enables the use of the copper-treated fibres in many manufacturing processes without alerhg manufacturing procedures or equipment, allowing for rapid and simple production of fabrics with potent biocidal qualities. Animal studies demonstrated that the copper treated fibers do not possess skin sensitizing properties [1,18]. Furthermore, no individual who used socks containing copper-impregnated fibres to alleviate their athlete’s foot conditions reported any negative effects caused by the socks [18,19]. Similarly, none of 100 patients, who slept on sheets containing copper treated fibres, reported any adverse effects [18]. These findings are in accordance with the very low risk of adverse skin reactions associated with copper [12]. The possibility of introducing copper oxide into fabrics may have significant ramifications. One example is the reduction of nosocomial infections in hospitals. Although the contribution of airborne transmission of pathogens to nosocomial infections has been controversial, much data is accumulating in support of the notion that airborne transmission of bacteria contributes significantly to hospital acquired infections (reviewed in Ref [20]). Airborne transmission is known to be the route of infection for diseases such as tuberculosis and aspergillosis. Recently it has been implicated in nosocomial outbreaks of MRSA [2 1,221, Acinetobacter baumannii [23] and Pseudomonas aeruginosa [24]. It was found that 65% of the nurses who performed activities on patients with MRSA in wounds or urine, contaminated their nursing uniforms or gowns with MRSA [20]. Hospital ventilation systems have also been implicated with nosocomial MRSA outbreaks [20]. Importantly, it has been demonstrated that sheets which are in direct contact with the patient’s skin and its bacterial flora are an important source of airborne bacteria [25,26], including MRSA [27l. Activities, such as bed-making, have been shown to release large quantities of micro-organisms into the atmosphere, only to fall back to background levels 30 minutes after bed-making. The data for the hallway also revealed that the bed-making process dispersed micro-organisms around the building [28]. In an ongoing study at the Banilai Hospital in Israel, bacterial colonization of sheets, including MRSA, has been found in 22 out of 30 sheets examined (Dr. Y. Mishal, personal communication and Ref [18]). MRSA spread also occurs though indirect contact by touching objects such as towels, sheets, wound dressings and clothes contaminated by the infected skin of a person with MRSA (CDC, Fact Sheet. 7 March 2003. Mt~://www.cdc.~ov/ncidod/dhaR/ar m a ca public.htm1). We submit that the use of self-sterilizing fabrics, such as pyjamas, sheets and pillow covers, in a hospital setting, will significantly reduce the airborne and inchect contact dissemination of bacteria and other micro-organisms in hospital wards, thus reducing the rate of nosocomial infections. Indeed, prehinary data with 30 patients, who slept overnight on regular sheets and then overnight on sheets containing 90% regular cotton fibres and 10% copper oxide-impregnated fibres, demonstrate a statistically significant lower bacteria colonization on copper oxide-containing sheets than on regular-sheets [18], strongly supporting our hypothesis. 0 Woodhead Publishing Limited, 2010

19

House dust mites O M ) are considered to be an important source of allergen implicated in allergic asthma, rhinitis, conjunctivitis and dermatitis [29]. By using copper oxide containing fibres in fabrics, the HDM population can be controlled and, if enough copper is present in the fabric, the mites can be eliminated entirely. In conclusion, this paper presents potential uses of copper in new applications that address medical concerns of the greatest importance. Implementation of even a few of the possible applications of this technology may have a major effect on the lives of many.

REFERENCES 1 G Borkow and J Gabbay, 'Putting copper into action: copper-impregnated products with potent biocidal activities,' FASEB J2004 18 1728-1730.

2 S S Block, 'Definition in terms,' Disinfection, Sterilisation and Preservation, 2001 9 1857. 3 H H A Dollwet and J R J Sorenson, 'Historic uses of copper compounds in medicine,' Trace Elements in Medicine, 2001 2 80-87.

4 T E Cooney, 'Bactericidal activity of copper and noncopper paints,' Infect. Control HOT. Epidemiol. 1995 16 444-450.

5 J J Cooney and R J Tang, 'Quantifying effects of antifouling paints on microbial biotilm formation,' Methods Enzymol. 1999 310 637-644.

6 J E Stout, Y S Lin, A M Goetz, and R R Muder,'Controlling Legionella in hospital water system: experience with the superheat-and-flush method and copper-silver ionization,' Infect. Control Hosp. Epidemiol. 1998 19 911-914. 7 D J Weber and W H Rutala, 'Use of metals as microbivides in preventing infections in healthcare,' Disinfection, Sterilization, and Preservation. S . S . Block, ed., (Lipphcott Williams and W i W , New York, 2001), 415-430.

8 W D Fraser, A Quinlan, J Reid, and R N Smith, Huntingdon Res Center: Primary screening of copper compounds for herbicidal, nematocidal, fungicidal and bactericidal activity. INCRAProjectno.211,43.2001. 9 'Copper IUDs, infection and infertility,' Drug Ther. Bull. 2002 40 67-69.

10 X Bilian, 'Intrauterine devices,' Best. Pract. Res. Clin Obstet. Gpaecol. 2002 16 155-168.

1 1 D Hubacher, R Lara-Ricalde, D J Taylor, F Guerra-Infante and R GuzmanRodriguez, 'Use of copper intrauterine devices and the risk of tubal infertility among nulligravid women,'N. Engl. JMed 2001 345 561-567. 12 J J Hostynek and H I Maibach, 'Copper hypersensitivity: dennatologic aspects--an overview,' Rev. Environ. Health 2003 18 153-183. 20


13 G Borkow and J Gabbay, 'Copper as a biocidal tool,' Curr. Med Chem 2005 12 2 163-2175. 14Z Ahmed, B D Idowu, and R A Brown, 'Stabilization of fibronectin mats with micromolar concentrations of copper,' Biomaterials, 1999 20 201-209. 15 Z. Ahmed, A Briden, S Hall, and R A Brown, 'Stabilisation of cables of fibronectin

with micromolar concentrations of copper: in vitro cell substrate properties,' Biomaterials, 2004 25 803-812. 16 I Tenaud, I Sainte-Marie, 0 Jumbou, P Litoux, and B Dreno, 'In vitro modulation of keratinwyte wound healing integrins by zinc, copper and manganese,' Br. J Dermatol. 1999 140 26-34. 17 R W Gorter, M Butorac, and E P Cobian, 'Examination of the cutaneous absorption of copper after the use of copper-containingointments,' Am JTher. 2004 11 453-458.

18 J Gabbay, J Mishal, E Magen, R C Zatcoff, Y Shemer-Avni, and G Borkow, 'Copper oxide impregnated textiles with potent biocidal activities,' Journal of Industrial Textiles, 2006 35 323-335. 19R C Zatcoff, 'Healthstidem Socks - Footware to a higher standard,' Podiatry Management, 2005 NovemberAlecember, 202-203.

20 C B Beggs, The airborne transmission of infection in hospital buildings: fact or fiction? Indoor Built Environ, 2003 12 9-18. 21 E A Mortimer, Jr., E Wolinsky, A J Gonzaga, and C H Rammelkamp, Jr., 'Role of airborne transmission in staphylococcalinfections,' Br. Med. J. 1966 1 3 19-322. 22R D Wilson, S J Huang, and A S McLean, 'The correlation between airborne methicillin-resistant Staphylococcus aureus with the presence of MRSA colonized patients in a general intensive care unit,' Anaesth. Intensive Care, 2004 32 202-209. 23 A T Bemards, H M Frenay, B T Lim, W D Hendriks, L Dijkshoom, and C P van Boven, 'Methicillin-resistant Staphylococcus aureus and Acinetobacter baumaunii: an unexpected difference in epidemiologic behavior,' Am J Infect. Control, 1998 26 544551. 24 H G Grieble, T J Bird, H M Nidea, and C A Miller, 'Chute-hydropulping waste disposal system: a reservoir of enteric bacilli and pseudomonas in a modem hospital,' J Infect. Dis. 1974 130 602-607. 25 D Coronel, A Boiron, and F Renaud, 'Role de l'infection sur la contamination microbienne des draps des patients,' Reanimation, 2000 9s 86-87. 26 D Coronel, J Escarment, A Boiron, J Y Dusseau, F Renaud, M Bret, and J Freney, 'Infection et contamination bacterienne de l'environnement des patients: les draps,' Reanimation 2001 lOS, 43-44. 0 Woodhead Publishing Limited, 201 0

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27 V W Greene, R G Bond, and G S Michaelsen, 'Air handling systems must be planned to reduce the spread of infection,' Mod Hosp. 1960 95 136- 144. 28 T Shiomori, H Miyamoto, K Makishima, M Yoshida, T Fujiyoshi, T Udaka, T Inaba, and N Hiraki, 'Evaluation of bedmakm * g-related airborne and surfme methicillinresistant Staphylococcus aureus contamination,' J Hosp. Infict. 2002 50 30-35. 29 S A Brunton and R L Saphir, 'Dust mites and astha,' Hosp. Pract. (OfM) 1999 34 67-2,75.

22


A REVIEW OF TBE ROLE OF MICROWAVES IN THE DESTRUCTION OF PATHOGENIC BACTERIA A. S. Lamb and E. Siores Institute for Materials Research and Innovation,The University of Bolton, Bolton, Deane Road,BL3 5AB,UK

ABSTRACT The destruction of food bacteria has been the subject of research and development in many disciplines for a very long time. Solutions have emerged from time to time but ultimately resulted in the on-going quest for keeping abreast of new bacteria strains emanating from old. Methods and techniques have proved to be reactive rather than proactive and thus the challenge has been a perpetual and a prevalent one. This paper provides a state of the art potential avenue for bacteria destruction using microwaves and outlines the work that has been undertaken by various researchers in the field. Outcomes presented support, to a certain extend, the viability of fixed frequency microwaves in the treatment of food bacteria and suggest especially that the pulsed microwave methods and techniques used can lead to the desired aims and objectives. However, their successful implementation in industry has been limited due to the fact that at fixed frequency microwave energy is absorbed not only by the bacteria but also by the food carrier. In this case, the benefits of the technology have not been fully realised since bacteria are ultimately thermally treated but often destructed at lower temperatures than conventional. The possibility of utilising pulsed microwaves and variable microwave frequency approaches are explained together with the advantages and limitations for the destruction of bacteria without affecting the carrier load.

Key words:Variable frequency microwaves, microbacteria, pathogenic bacteria sterilization, food poisoning, microwaves

MICROWAVEINTERACTIONS WITH MATERIALS Bows (1999) provided the following equation for calculating the microwave power penetration depth, Equation 1

where D, is in centimetres, f is in GHz and E’ is the dielectric constant, whilst E” is the dielectric loss factor, Simply, the higher the frequency, the less the depth of penetration. E’ and E” can be dependent on both frequency (0 and temperature, the extent of which depends on the foodstuff to be studied. The rate of microwave heat generation per unit volume, Q, at a particular location within the foodstuf€during the microwave irradiation process is given by the following equation from Buf€ler(1993), and Datta and Anatheswaran (2000): Q =2 A f

E”

E2


Equation 2 23

where E is the strength of the electric field of the wave at the location, f is the frequency of the wave (typically 2450 MHz), EO is the permittivity of free space (a physical constant), and E” is the dielectric loss factor ( a material property called the dielectric property representing the material capacity to absorb microwaves). There is another dielectric property, dielectric constant,which affects the strength of the electric field inside the food product. The dielectric property depends on the composition of the food product, with moisture and salt being the two determinauts of variability interest (Mudgett 1986). The subsequent temperature rise in food depends on the duration of heating, the location of the food in the reactor, the convective heat transfer at the surface and the extent of evaporation of the water inside the food and at its surface (United States Food and Drug Agency 2000). Furthermore, Calvao and Olano (1992) concluded that heating by microwaves can be faster and more uniform thus being more effective and efficient than conventional heating.

FIXED F’REQUENCY MICROWAVE INTERACTIONS WITH BA-RIA The temperature increase in some materials when exposed to high fiequency electromagneticfields (above 108Hz)has been known since 19th century and utilised in limited applications in the early part of the 20th century (Zlotorzynsk 1995). In conventional thermal processes, slow heat conduction &om the heating medium to cold spots in the food stuff, often results in treatment of the material at the periphery of the heating container which is far more severe than that required to achieve commercial sterility (Datta and Hu 1992). Microwave energy is a non-ionizing form of radiation and as such it has been tested to study the effectiveness in destroying bacteria and extending the shelf life of meat products without aEecting the quality, taste or reducing the weight of the product. The microbial treatment under microwaves irradiation is a function of power, firesuericy range, time and temperature. The technique using fixed frequency microwaves has been used in the pasteurization of milk, yoghurt and dairy products and has had an effect on reducing the bacterial count and deactivating enzymes at a lower energy input level and destruction as compared with conventional means of pasteurizationtechniques in use (US Food and Drug Administration2000). Sterilization was amongst the earliest applications considered for microwave usage (Fleming 1944; Electronic Sterilization 1945; Swenson 1949) and this went hand in hand with the exploration of the biological effects of the microwaves on cells. The main advantages of the fixed frequency microwaves (at 915MHz and 2450MHz) were that it allowed continuous sterilization through microbial destruction (Mudgett 1986:Mudgett and Schwartzberg 1982) and as such industrial microwave pasteurization and sterilization have been reported for over forty years (Jeppson and Harper 1967:Kenyon et al 1970: Mudgett and Schwartzenbenrg 1982: Decareau 1985: Schlegel 1992: H a r h g e r 1992:Topps 2000) There has also been investigation with regards to pasteurization means for hermetically sealed food packaging including meat, provided that the packaging material is transparent to microwave energy. Since different areas are subjected to different power levels at different times, the power distribution can be uneven and can result in multiple hot spots within the food product (Laufet al, 1993). It is timely to reveal the effect of fixed frequency microwaves on a number of bacteria and the following section summarises results that have been obtained so far.

24


WORK CARRIED OUT AT THE UlVVERSlTY OF BOLTON The microwave power input parameters were optimised through the irradiation of Escherichia coli, Stavhvlococcus aureus and Salmonella DOOM, which has been investigated through exposure to fixed frequency microwaves at varying time sets of 10 seconds, 30 seconds and 45 seconds and low power ranges between 50W and 300W. The lethal effect of the treatment was validated via the use flow cytometry.

H s

120

100

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Paver (w)

3mw

2mw

IOOUV

ww

T i W P o w e r Settings

Figure 1. Effect of E. coli at Merent power settings and different time intervals. It is evident from Figure 1, that at each power setting the initial reading at ten seconds shows approximately about a half population cell mass reduction, ranging h m 41.13% at 200W and up to 62.34% at 50W. The reduction then increases at 30 second time interval with higher bacterial mass reduction rate at 300W (88.52%) and the lower kill rate of 73.11% at 200W. The highest bacterial kill effect (98.1%) is observed at 45 second interval at 300W power setting. On the other hand, the lowest readings are observed at 200W and lOOW of 89.65% kill rate, in both cases. With regard to Staphylococcus aureus, it is evident from Figure 2 that the greatest bacterial kill rate of 84.27% is achieved at 10 seconds time interval at lOOW, whilst the lowest rate of 31.4% is observed at 50W. At 30 second time interval, the kill rate of 88.38%, 89.4%, 91.42% and 87.18% for 330W, 200W, lOOW and 50W power settings are obtained respectively. The results at 45 seconds show the bacterial masses of 99.9%, 97.44%, 98.7% and 96.48% for the power settings of 300W, 200W, lOOW and 50W respectively.


25

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Figure 2. Effect of Staphylococcus aureus at different power settings and different time intervals It can be seen in Figure 3 that at each power setting the Salmonellapoona reduction rate is quite low when compared to higher power settings. At 300W the reduction rate is only 34.42%,at 200W it is 48.67%a better result showing an almost half population of bacteria is destroyed. At lOOW and 50W the kill rates are 29.83% and 20.46% respectively. As the exposure time is increased to 30 seconds the kill rates increase to 68.96%for 300W, 79.54%for 200W, 76.1% for lOOW and 70.04%for SOW,thus the rate increased as did the exposure time as would be expected. At 45 seconds exposure time the reduction rates are 90.91%, 89.57%, 93.98% and 96.18% for the respective 330W, 200W, IOOW and 50W power settings.

Pawar

(w)

Timepower Settings

Figure 3. Effect of Salmonellapoona at different power settings and different time intervals

26


FLOW CYTOMETRY Flow cytometry is a technique for counting, examining and sorting microscopic particles suspended in a stream of fluid. It allows simultaneous analysis of different cell parameters such as physical andor chemical characteristics of single cells flowing through an optical and/or electronic detection apparatus. A beam of light of a single wavelength is directed onto a hydro-dynamically focused stream of fluid. A number of detectors are aimed at the point where the stream passes through the light beam; one in line with the light beam (Forward Scatter or FSC) and several perpendicular to it (Side Scatter (SSC) and one or more fluorescent detectors). Each of suspended particles in the solution being measured which pass through the beam scatters the light in some way, and fluorescent chemicals found in the particle or attached to the particle may be excited into emitting light at a lower ftequency than the light source. This combination of scattered and fluorescent light is picked up by detectors present in the Flow Cytometer. Figures four and five show a Flow Cytometxk representation of dead cells and the Irradiated sample subjected to 50W for 45 Seconds. 1000

1000

100

100

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CONCLUDING REMARKS

The low time high power approach undertaken compliments the work of Cunningham and Albright (1977) and Cunningham 1978; 1980 who applied microwaves to poultry meat for shorter periods of time. Meat treated in less than 20 seconds showed “no drastic changes in appearance ofphysical characteristics.” (Cunningham, 1980). Results obtained for Staphylococcus aureus at the higher power settings of 200W i.e. kill rates of 97.44% and 89.40% at 45seconds and 30 seconds respectively and results obtained at 300W at 30sconds and 45 seconds of cell mass reduction rates of 88.38% and 99.9%respectively compare favourably to the work canied out by Yeo et al(1999) who reported a total kill at 11 0 seconds but at the higher power settings of 800W. This similar pattern has been observed in all the power time relationships tested, with an 0 Woodhead Publishing Limited, 2010

27

initial kill rate that rose with the exposure time and the final bacterial destruction rate is always around the 95% level. With respect to Escherichia coli the same pattem of rising bacterial cell mass reduction rates has been observed with the final figures of: 300W giving 98.1% effectiveness, at 200W the figure is 89.65% at lOOw the figure is also found to be 89.65%. The figure for bacterial death rate obtained for Exoli is 94.9%. This suggests that this power level and exposure time are the optimum time and power settings. This is also supported the work of Meng and Doyle (1998) who reported that E.coli is destroyed by hating at 68.3OC for 16 seconds, allied to this Yaghmaee and Durance (2005) investigated the effects of microwaves on the survival and injury of E.coli. They reported that E.coli is sensitive to temperature change under microwave heating; this theory was backed up by the work carried out in this experiment. The flow cytometry work as represented by Figures 3 and 4 prove that the microwaves at low power and time have optimum killing rates and have a biocidal effect. We can conclude that each bacterial type has an optimum temperature and time relationship which gives maximum cell mass reduction. The work was carried under controlled conditions, with the microwave irradiation canied out in the confiies of a waveguide as opposed to the cavity of a microwave oven. Throughout the experimental work the temperature of the carrier load did not exceed 4OoC meaning that microwave energy was reactive in destroying bacteria only without affecting the carrier load which could in theory be the foodstuff. The experimentation proved that bacteria can be destroyed through microwave process optimisation at relatively low levels of power input and exposure time at the fixed frequency of 2.45GHz. This finding argues that energy levels can be used for selective destruction without affectingthe carrier load.

Acknowledgements Engineering and Physical Sciences Research Council (EPSRC),UK. The Technical Staff,Institute for Materials Research and Innovation, The University of Bolton.

REFERENCES 1 J R BOWS,‘Variable frequency microwave heating of food’, J of Microwave Power and Electromagnetic Energv, 1999 34(4) 227-238. 2 C R Buffler, Microwave cooking andprocessing: Engineeringfirndamentals for the food Scientist, Van Nostrand Reinhold, New York, 1993.

3 M M Calvo and A Olano, Thermal treatment of goat’s milk, Cienc. Tecnol. Aliment, 1992 32(2) 139-152. 4 A K Datta, Fundamentals of heat and moisture transport for microwaveable food product and process development, A. K. Datta and R. C. Anatheswaran. (4s.). Handbook of Microwave Technology for Food Applications. Marcel Dekker, Inc. New York, 2000. 5 A K Datta and W Hy Quality optimization of dielectric heating processes. Food Technol,1992 46(12) 53-56.

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6 R V Decareau, Pasteurization and Sterilization. Microwaves in the food processing industry. Academic Press, 1985. 7 Electronic Sterilization,Am Niller Process, 1945 73(4) 43-48. 8 G A Evrendilek, Q H Zhang and E R Richter, (1999) ‘Inactivationof E.coli 0157:H7 and E.coli 8739 in apple juice by pulsed electric fields’, J of Food Protection 62(7) 793796.

9 H Fleming H, ‘The effects of high frequency fields on microorganisms’, Electrical Engineering, 1944 63( 1) 18-21. 10 L Harlfinger, ‘Microwavesterilization’,Food Technol, 1992 46(12) 57-61. 1 1 M R Jeppson and J C Harper, Microwave heating substances under hypostatic pressure. Cryodry Corporation. US Patent Office 3 335 253,1967. 12 E M Kenyon, D E Westcott, P La Casse and J Gould, ‘A system for continuous processing of food pouches using microwave energy’, J. Food Science, 1970 36(2) 289293. 13 R J Lauf, D W Bible, A C Johnson and C A Everleigh, ‘2-18 GHz broadband microwave heating systems’, Microwave J,November 1993 24-34. 14 R Mudgett, ‘Microwave properties and heating characteristics of foods, an overview’, Food Technology, 1996 M(6) 84-98.

15 R Mudgett and H Schwartzberg, (1982) ‘Microwave food processing: pasteurization and sterilization- a review’, American Institute of Chemical Engineers, Symposium Series, 78(2 18) 1- 1 1. 16 W Schlegel, ‘Commercial pasteurization and sterilization of food products using microwave technology’, Food Technol, 1992 46(12) 62-63. 17 T Swenson, Process for pasteurization and enzyme activity of fiuit by electronic heating, US Patent Office, Pat No 2 476 251,12 July 1949. 18 R Topps, Managing Director, Tops Foods, Lammerides 26, Olen, Belgium, 2000. Web Site- http://www.tomfoods.com

19 U.S Food and Drug Administration Centre for Food Safety Applied Nutrition (2000) Kinetics of Microbial Inactivation for Alternative Food processing Technologies Microwave and Radio Frequency Processing, http://www.f d a . g o v / F o o d / S c i e n c e R e s e a r c h / s d u c m 100158.htm 20 A Zlotorzynsk, ‘The application of microwave-radiation to analytical and environmental chemistry’, Critical Revs in Analytical Chem, 1995 25 43-76.


29

ANTIMICROBIAZ,BIOACTLVE BAND-AIDSWITH PROLONGED AND CONTROLLED ACTION Petar Skundric', Ljiljana Simovic', Mirjana Kostic', Adela Medovic', Katarina Milosevic2,Suzana Ditrijevic' 'Faculty of Technology and Metallurgy, Belgrade, Serbia 'Faculty of Pharmacy, Belgrade, Serbia

ABSTRACT The paper discusses the antimicrobial bioactive band-aids, a modem means of wound management and healing, which are effective against a wide spectrum of microorganisms. Ion-exchange fibres and nonwoven textile materials composed of PP/viscose blend were used as a textile basis. Antimicrobial bioactive band-aids were manufactured in two routs: - by chemisorption of gentamicin sulfate by ion-exchange fibres; and - by adhesion of gentamicin sulfate on nonwoven material with the aid of a polymer carrier (chitosan). For assessment of antimicrobial activity, the diffiion method on an agar medium has been used. Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella, Escherichia coli and Candida albicans have been utilised. The kinetics of active substance desorption has been examined through dissolving rate of medical substance fiom transdermal band-aid in vitro. Physical-chemical foundations and kinetics of desorption of gentamicin sulfate in vifro are described by a mathematical model which can be used for prognosis of prolonged release of medical substance fiom band-aid as a transdermal system.

Key words: Bioactive textile, antibacterialfibres, gentamicin sulfate INTRODUCTION Last decades of the 20& century were marked by an emphasiig of the protection of man's health and its prevention from infections by microorganisms' actions. It is well known that disinfection materials offer almost an instantaneous, but short lasting solution for microbes' removal. On the contrary,antimicrobial remedies are produced to offer a long-lasting solution for pathogeneous microbes' elimination. A great contribution to R&D of antimicrobial materials gave researchers fiom Japan, USA, Switzerland, Great Britain, Russia, Poland, Austria and France. However, the greatest contribution undoubtedly belongs to Japanese, in this moment presenting world leaders in manufacturingof antimicrobial textile materials [1-20]. For manufacturing antimicrobial textiles many inorganic antibacterial (resistant on high temperatures) agents are used. Good samples contain metal silver and zinc ions built into fibres during polymer synthesis process or during spinning of chemical fibres. Literature survey related to the application of antibacterial preparations for suppression and destroying of infection in different kinds of wounds shows that silver in fibres [3141, fabrics [4-7,181 knits [8,9] and nonwovens [10,11] has been used extensively. Besides silver, both zinc and copper are also used as antibacterialpreparations. For treatment of natural fibres, many organic antibacterial chemicals are used, for example quaternary ammonium compounds [14]. Among numerous antimicrobial 30


textile materials, special attention should be paid on antimicrobial biotextile materials used for wound dressing and healing. The amplification of antimicrobial action may be attained by using special antibiotics or their combination [15-20]. At the Textile Engineering Department of the Faculty of Technology and Metallurgy in Belgrade, an intensive research on biomedical textile materials with antimicrobial and combined effects is recently conducted. Besides antibiotics, honey and essential oils of different plants - fir, rosemary and St.Joh’s worth- were used to attain biological activity of medical textile materials [21-241. To impart antibacterial activity on textile materials the following techniques were used: chemical modification ensuring biocide or biostatic bondmg on fibre by chemical bonds (chemisorption); - fixation of preparation into super molecular structure of fibre according to inclusion type (physical bond), i.e. physical modification; and - deposition of preparation on fibre in the form of low-soluble substances, by means of polymers or low-molecular agents-mediators (possibility of bonding by any bond type and in Merent modifications).

-

It has been shown in our previous research [22] that antimicrobial biomedical textile material based on PAN fibres and nonwoven textile showed considerable activity against different strains of bacteria. The amounts of bonded antibiotic are sufficient to impart desirable antibacterial activity in fibres due to the fact that Gram-negative bacteIia strains (Escherichia coli and Pseudomonas aeruginosa) are sensitive to gentamicin with minimum inhibitory concentrations within a range of 0.06 to 8mg per ml. Among the Gram-positive organisms, most strains of Staphylococcus aureus are highly sensitive to gentamicin with minimum inhibitory concentrations within a range of 0.12 to lmg per ml[25]. In this work, kinetics of removal of antibiotic deposited in vitro has been studied with the use of Franc’s cell for continual removal of medicals.

EXPERIMENTAL Materiala Fibrous materials 0 Ion-exchange acrylic fibres (PAN), with ion-exchange capacity (IEC) 2,O and 3,O mmollg and with linear density 2,2 dtex Nonwoven fabric based on ion-exchange acrylic fibres, with ionexchange capacity (IEC) 3,O 0 Nonwoven fabric based on blend of polypropylene/viswse, both fibres having same linear densities- 1,7 dtex. Antimicrobial agents Gentamicin sulfate, a product of pharmaceutical industry “Galenika”, Belgrade

Preparation of antimicrobialband-aids In this work, biotextile antimicrobial medical plasters have been designed and developed by using the following two methods: 0 Woodhead Publishing Limited, 201 0

31

-

gentamicin sulfate chemisorption by PAN fibres and by nonwoven ionexchange fabric based on PAN; and adhesion deposition of gentamicin sulfate on the surfw of nonwoven textile material, PP/viscose, with the help of polymer carrier- chitosan [20,22,23].

Dissolution studies In vitro, drug release was studied in the physiological solution (0.95% NaC1) and in phosphate-buffered saline. Gentamicin sulfate release fiom antimicrobial fibres was carried out by submerging the fibre-gentarnicin sulfate complex into a physiological solution (0.95% NaCl). After that, gentamicin sulfate release was monitored. Gentamicin sulfate release h m the fibre (physiological solution) was measured in vitro by a Shimadzu W-260 W-vis spectrophotometer. Releasing of bonded gentamicin sulfate has been studied in vitro, in physiological solution (0,95% NaCl), under the following conditions:

- physiological solution (0,95% NaC1);

-

desorption time: 1,5,10,15,30,45,60,120,1440 temperature of desorption: 25+ 2OC; pH of physiological solution: 7.0; and liquor ratio: 1:400.

min;

Skin penetration and gentamicin release fiom the antibiotic/polymer complexes was measured in vitro by Franz diffusion cell technique [26]. The gentamicin release was studied in 500 ml of phosphate-buffered saline (PBS, pH 7.4) at 370 C in a mild shaking environment (75-100 r.p.m.). Aliquots of 3 ml were assayed for gentamicin at the time points of 0, 0.25,0.5, 0, 75, 1,2,3,4, 5,6, 12 and 24 h. For assessment of the quantity of gentamicin sulfate released, HPLC (High-performance liquid chromatography) method has been used. Inhibition activity has been determined by diffusion method on agar plate. The antimicrobial efficiency of this bioactive transdermal system was examined on an agar plate seeded with indicator microorganisms (Staphiolococcus aureus ATCC2.5923, Echerichia coli ATCC2.5922, Pseudomonas Aergenosa ATCC9023, Candidia albicans ATCC2.592, Klebsiellapneumoniae ATCC4352). Samples were tested after 24 hours lasting incubation at 37OC by recording the presence or absence of visible colonies on the agar surface directly above the fibrous textile material. After visually inspecting agar surface, inhibition zone (bactericidal and bacteriostatic)was determined.

EXPERIMENTAL, RESULTS AND DISCUSSION The results of gentamicin sulfate quantities bonded by fibres and nonwoven materials are presented in Table 1. Depending on the antimicrobial textiles manufacturing procedure selected, fibres and nonwoven textile material were bonded using different quantities of gentamicin. From the data presented in Table 1, it is obvious that the greatest quantity of gentamicin was bonded on ion- exchange nonwoven material based on PAN fibres. Taking into account of the ion-exchange properties of the substrate, both chemical and physical bonding of gentiunicin on polymer matrix were carried out. 32


Table 1. Quantity of bonded gentamicin sulfate by fibrous material

Type of fibrous material

Quantity of bonded gentamicin sulfate ____________~ 11OJ mg/g fibre Ion-exchange 112,3 mg/g fibre - PAN fibres 1 18,2 mg/b fibre 3.67 rnn/crn' Nonwoven ion-exchange 3.12 rngkrn' material based on PAN 2.77 rng/cm' 2.53 mg/crn' 1.0 mg/cm' Nonwoven material 0.9 mg/cm' PP/viscose 0.1 ing/cm' 0.09 rng/crn'- __ -~ _ _ ~

Desorption process develops slowly. It comprises a mdtistadium process and encompasses the following phases: diffusion of physiological liquid in polymer- carrier, swelling of polymer- carrier and increasing its porosity, breakage of primary and secondary bonds between gentamicin and polymer and, finally, diffiion of gentamicin molecules from polymer to the selected place in the organism. Figures 1-3 represents the kinetics of gentamicin sulfate release from antimicrobial textile obtained in physiological solution (Fig. 1.) and in Franz cell (Fig. 1,2 and 3).

Tme, min

-h

Figure 1. Cumulative amount of gentamkin released h m complex "PAN ion-exchange fibre - gentamicin sulfate"


Figure 2. Cumulative amount of gentamicin released h m the complex "nonwoven PAN - gentmicia" obtained by chemisorption(Franz cell)

33

6

2lPzl2#?6

Ihn;hrus

Figure 3. Cumulative amount of gentamicin released h m complex "gentamicinnonwovenPP/viscose"obtained by adhesion

Results of inhibitory activity of textile material treated with gentamicin sulfate are presented in Table 2 and in Fig. 4. Table 2: Inhibitory activity of nonwoven fabric test sample treated with gentamicin sulfate

; Time 5 min 10 min

15 min

E. coli

s.anmr

6 6, 5 7

10 10

P.

C.

9. 5

10. 5

10 10 7. 5

12 12 12

10. 5 10 10 9, 5 8, 5 6 5.5 3

30 min 60 min 120 min 24 h One month

5

7,5 9, 5 5.5 7, 5 3. 5 8 3, 5+2, 5 (d) 6 0, 8

4 4,s

4,5+2,5 (d)

10 8 7

Control sample

7

7,5

14, 5

11

11,5

From these results it is obvious that antimicrobial textile material demonstrates an inhibitory activity towards a l l indicatory microorganisms. The strongest effect is observed with P.Aeruginosa and C.Albicans. The widths of inhibition zones slightly decrease with the time the sample spend in physiological solution before application on selected strains of bacteria.


E. Coli

S. Aureus

P.Aeruginosa

&lebsiCllo

C. Albicans

Fig.4. Inhibition of the growth of tested microorganisms treated with antimicrobial material "PP/viscose-gentamicin sufate 0,lmg/cm2", which spent 5, 10 and 15 min in physiological solution. It is just the reason why the widths of inhibition zones are bigger in control samples (samples which did not stand in physiological solution), with exception of indicatory strain Mebsiella. In this case the widths of inhibition zone in samples which dwelled in physiological 5,lO and 15 min are greater than those of control sample. The reason for such a phenomenon could be manifold. There is, before all, the question the diffusion of the active substance through the support (i.e. the weakening of the bond between textile and the preparation). The second reason could be the sensitivity of Klebsiella sp. on gentamicin sulfate concentrations, being attained on the borders of the inhibition zone. Starting from the Fickian law which describes d i f i i o n and fkom experimental results, a mathematical dependence of gentamicin release from antimicrobial band-aid (plaster) has been obtained in the following form:

y = a ( l - e q . .........................................................................................(1) where are: y-cumulative quantity of gentamicin sulfate released, k-the speed of releasing, t-time, a- parameter dependent on starting sample characteristics and desorption conditions. Fig. 5 and Fig. 6 show the models for samples obtained in different experimental conditions of antibiotic release.

---1

70-

y=60,67(leq""? ~=63,95(1e~~~)

9

y=66,07(le"."O")

A

0

2

0

4

o

I - ./ /

m

210

m

rimin

Figure 5. Mathematical model of gentamicin release from complex ,,gentamicin-nonwoven fabric PPIviscose'', obtained by adhesion of

Figure 6. Mathematical model of gentamicin release from complex ,,PAN ionexchange fibre - gentamicin sulfate", obtained by chemisorption

antibiotic 0 Woodhead Publishing Limited, 201 0

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On the base of mathematical model it is possible to calculated particular values of parameters a and k h m equation (1). It may be seen that this mathematical model shows a high degree of agreement with experimental results (correlation coefficient surpassing 0, 99, so that its use for prognosis of gentzunicin sulfate behavior after application could be highly recommended.

CONCLUSION Medical band-aids with immobilized gentamicin sulfate showed a large spectrum of intense antimicrobial activity towards gram (+) and gram (-) bacteria and fungi. It has been found that band-aids have a prolongated effect and a high activity even with concentrations of active substance lower than 0,l mg/cm2. On the basis of the kinetics of the release of gentamicin sulfate studied, a mathematical model describing the process of medicine release is obtained.This model can be used for prognosis of prolonged release of medical substance from band-aid as a transdermal system.

REFERENCES 1 S Rajendran, S C Anand, ‘Development of a versatile antimicrobial f i s h for textile materials for healthcare and hygiene application’, Proceedings of the 2nd Int Conf, Medical textiles, 24th t 25th August 1999, Bolton Institute, UK, Edited by Subhash h a n d , Woodhead Publishing (April 2000) 107-116. 2 L Wang, J Xie, L Gu, G Sun, ‘Preparation of antimicrobial polyacrylonitrile fibres: blending with polyacrylonitrile-co-3-allyl-5,5-dimethylhydantoin’,Polymer Bulletin, 2006 56(2/3). 3 www.swicofil.cod~rodu~O55chitosan.html

4 E Wilk, G Dyiworska, ‘Antimicrobial properties of silver content textiles’, 5* World Textile Conjirence A UTEX 2005, Portorof,Slovenia (June, 2005), Proceeding, p.267. 5 U Klueh, V Wagner, et all., ‘Efficacy of silvercoated fabric to prevent bacterial colonization and subsequent device-based biofilm formation’, Biomed Muter.Res, 2000 53(6) 621.

6 www.nsti.ore/Nanotech2005/showabstract.hto=198 7 E A Deitch., A A Marino, T E Gillespie, J A Albright, ‘Silver-nylon: a new

antimicrobialagent’, Antimicrobial Agents and Chemotherapy, 1983 23(3) 356, 8 www.blockemf.com/catalog/vroductinfo.DhD?uroducts id=5090

9 http://www.silverlon.Lcom/burn product descriptomhtml 10 D Parsons, P G Bowler, V Myles, S Jones, ‘Silver antimicrobial dressing in wound management: a comparison of antibacterial, physical, and chemical characteristics’, Woundr, 2005 17(8) 222. 11 www.aerrisasia.com/imDrovenonwovens.html 36


12 httD://www.azonano.com/details.as~?ArticleID=3 16

1 3 www.fasebi.orp;/cgi/content/abstract/04-2029fie 14 Y Endo, T Tani, and M Kodama, ‘Antimicrobial activity of tertiary amine covalently bonded to a polystyrene fibre’, Appl Environ Microbiol. 1987 5 x 9 ) 2050-2055.

15 T N Yudanova, I V Reshetov, ‘Modern wound dressings: manufacturing and properties’, Pharmaceutical Chem .J 2006 40(2) 85-92. 16 T L Yurkshtovich, V A Alinovskaya, N S Butrim, D S Zimnitski, ‘Kinetics of antibiotic sorption by monocarboxyl cellulose’, ColloidJ, 2004 66(l) 100-105. 17 M Roby, Heterogeneous yams for surgical articles, US Patent Office, Pat No, 20050125036. 18 W Shalaby, Shalaby. ‘Antimicrobial fabrics’, US Patent Ofice, Pat No, 6780799. 19 J Buchenska, J Tazbir., ‘Antibacterial chinugical threads containing cephalosporine of forth generation’, Int ConfMEDTEx2005,39-43.

20 J Buchenska, ‘Pan fibres with antibacterial properties’, Fibres & Textiles in Eastern Europe, 1996 4(1) 53-59. 21 P Skundric, A Medovic, Lj Simovic, S Dirnitrijevic, M Kostic, M Janicijevic, B Milakovic, ‘Boimedical antimicrobial textile materials of broad spectrum activity’, V Int C o d MEDTEx2005 24-27. 22 P h u n d r i k , A Medovik, M Kostik, ‘Fibrous systems with programmed biologicalactivity and their application in medical practice’, AUTEXRes J, 2002 2(2) 78-84. 23 P Skundric, A Medovic, Lj Simovic, S Dimitrijevic, M Kostic, ‘Development and characterization of antibacterial bioactive fibres as W e d therapeutic systems’, 5th World Texrile Conf A U T . 2005, PortoroZ, Slovenia, June 27-29,Book 1, p.232, (2005). 24 T Mihailovic, K Asanovic, Lj Simovic, P Skundric, ‘Influence of an antimicrobial treatment on the strength properties of polyamide/elastane weft-knitted fabric’, J of Appl Polymer Ski, 2006 103(6) 4012-4019.

2 V M Varagic, and M P Milosevic, ‘Pharmacology (in Serbian), Elit-Medica, Belgrade (1 994). 26 C Goosen, et al., ‘A comparative study of an in situ adapted diffision cell and an in vitro Franz diffusion cell method for transdermal absorption of doxylamine’, Eur J Pharm Sci. 2001 13(2) 169-77.


37

COlMPARISON OF ANTIMICROBIAL TEXTILE TREATMENTS E. J. Smith', J. T. Williams', S. E. Walsh' and P. Painte2 'Textile En 'neering and Materials Research Group,De Montfort University, Leicester, UK, Leicester School of Pharmacy, De Montfort University, Leicester, UK

P

ABSTRACT In recent years there has been an increase in the range of antibacterial textile based products available, especially in hygiene-sensitive sectors such as the health sector and the foodstuffs industry. These can range h m simple wipes to wound dressings and clothing applications. This increase in use has created a need for more microbiological data about the effectiveness of merent types of treated fabrics under a variety of conditions in which they may be used. Current standard test methods may not accurately reflect some of the in-use conditions. Using standard and amended test methods, commercially available textile products claiming antimicrobial properties were assessed against Staphylococcus aureus. Active ingredients of the treated antimicrobial textiles included silver, quaternary ammonium salts and triclosan. Fibres claiming antimicrobial properties such as bamboo and soy were also tested. The different silver treatments assessed were manufactured by the application of silver to the fabric as an after-treatment or inherent in which silver is added to the fibre during the spinning stage or coated on thread. The commercially available textiles were subjected to conditions ranging from wet, in which the samples were incubated in an aqueous bacterial suspension, to dry bacterial applications. This was to determine whether the antimicrobial activity of fabrics is a€€ected by differing moisture levels so that predictions of the in-use activity of commercially available antimicrobial textile based products can be made more accurately.The efficacy of the "treatments" is presented for the various product categories under different conditions of wetness which may have application in the clothing industry. INTRODUCTION In recent years there has been an increase in the range of antimicrobial textile based products available, especially in hygiene-sensitive sectors such as the health sector and the foodstuffs industry". These can range h m simple wipes to wound dressings and clothing applications. This increase in use has created a need for more microbiological data about the effectiveness of different types of treated fabrics under a variety of conditions and uses. Medical dressings are applied to wounds which are wet, but clothing is similar to the relative humidity of the room unless it is next to the skin and absorbing sweat. Current standard test methods may not accurately reflect some of the in-use conditions. Using standard and amended test methods, commercially available textile products claiming antimicrobial properties were assessed against StuphyZococcus aureus @. aureus). Antimicrobial textiles are usually manufactured either by the application of the antimicrobial agent to the fabric as an after-treatment finish or as an inherent treatment in which the antimicrobial agent is added to the fibre during the spinning process'. '. Active ingredients of the treated antimicrobial textiles tested included silver, quaternary ammonium salts and triclosan. Several different silver treated fabrics were 38 0 Woodhead Publishing Limited, 2010

assessed in which silver had been applied either as an after-treatment finish; as an inherent treatment; or as silver coated yamsd7 woven into the fabric. Fibres claiming antimicrobial properties such as bamboo and soy were also tested. The commercially available textiles were subjected to conditions ranging from wet, in which the samples were incubated in an aqueous bacterial suspension, to dry bacterial applications. This was to determine whether the antimicrobial activity of fabrics is affected by differing moisture levels so that predictions of the in-use activity of commercially available antimicrobial textile based products can be made more accurately. The efficacy of the "treatments" is presented for the various product categories under different conditions of wetness which may have application in the clothing industry.

MATERIALS AND METHODS Organisms

The Gram positive bacterium, S. aureus ATCC 6538 was used in all experiments.

Fabrics Various commercially available textiles claiming antimicrobial activity were examined (Table 1). Active ingredients of the treated antimicrobial textiles included silver, quaternary ammonium salts (QACs) and triclosan. The textile substrates for the treated samples were polyester or a polyester/ cotton blend. Fibres claiming antimicrobial properties such as bamboo and soy were also tested. Relevant untreated fabrics were examined as control samples. Table 1 Composition of the antimicrobialfabrics used in this study Material Polyester (50%) / cotton (50%) blend Polyester (50%) /cotton (50%) blend Polyester (50%) /cotton (50%) blend Polyester (98%) / silver coated thread (2%) Polyester (67%) I cotton (33%) blend Polyester (50%)/ cotton (50%) blend Triclosan - inherent Polyester (50%) /cotton (50%) blend Bamboo - regenerated fibre Bamboo (1 00%) Bamboo (60%) / Cotton (40%) blend Carbonised bamboo Carbonised bamboo / polyester composite - soy soy (100%) :Finish type A is a very fine colloidal suspension of silver tFinish type B is a microparticle composite of titanium dioxide containing soluble silver chloride *Silver coated threads woven as uniform stripes (approx 5mm apart) on polyester fabric visible on one or both sides 'Quaternary ammonium salt Antimicrobialagent Silver - after-treatment finish type A' - after-treatmentfinish type Bt - inherent Silver coated thread* QAC' - tinish


39

Test methods Three different standard quantitative test methods were chosen to evaluate the antibacterialproperties of the chosen commercially available textiles. These represented conditions from soaking wet to dry bacterial application.

AA TCC 100-2004 Assessment of Antibacterial Finishes' All samples were initially tested in duplicate using AATCC 100-2004,to evaluate the degree of antibacterial activity. This standard test is a quantitative test where the fabric absorbs a set amount of a bacterial suspension, it therefore provides moist conditions. The standard test time for incubating the inoculated fabrics is 24 hours, but in these tests a shorter incubation time of 6 hours, closer to the period of a working shift, was also undertaken. A 24 hour nutrient broth culture of S. aureus was diluted with sterile nutrient broth to give a final concentration of 1-2x los colony forming units (CFU) per ml. Sterilised circular swatches of each fabric measuring 4.8 cm in diameter were placed in a sterilised 250 ml glass jar. 1 ml of the diluted bacterial suspension was applied to each fabric swatch, ensuring even absorption. The jars were sealed and incubated at 37 "C for different contact periods; 0 hours, 6 hours and 24 hours. After incubation, 100 d of sterile distilled water was added to each jar and shaken for 1 minute. Serial dilutions were performed and were plated on nutrient agar using the Miles Misra method'. The plates were incubated for 24 hours at 37 "C and the number of CFU / fabric was calculated. The antimicrobial activity of the tested fabric samples was expressed as a log reduction, in which the mean log10 density of bacteria recovered fkom the inoculated test sample over a 6 or 24 hour contact time was subtracted from the mean log10 density of bacteria of that test sample immediately after inoculation (0 hours contact time). ASTM E2149-01 Standmd Test Method for Determining the AntimicrobialAgents under Dynamic Contact Conditions" To represent soaking wet conditions, the antimicrobial properties of specific test samples were evaluated in duplicate using ASTM E2149-01 (Dynamic Shake Test). This is a quantitative method where samples are incubated in an aqueous bacterial suspension under constant agitation to ensure good contact between the bacteria and the treated fabric". The standard states a contact time of 1 hour, but 24 hour contact time was also performed to see the efficacy over longer periods and to compare with the results from other test methods. A 24 hour nutrient broth culture of S. aureus was diluted with sterilised 0.3 mM phosphate buffer to give a final concentration of 1-2 x lo5 CFU / ml. 50 ml of the diluted bacterial culture was transferred to sterilised 250 ml glass jars to which 1.O g of test fabric, which had been cut into approximately 1 cm2 pieces then autoclaved, was added. The tops were screwed onto the jars and they were incubated and shaken at 120 rpm at 37 "C for 1 hour or 24 hours. After incubation, serial dilutions were performed and were plated onto nutrient agar using the Miles Misra method. The plates were incubated for 24 hours at 37 OC and the number of CFU / g of fabric was calculated. The antimicrobial activity of the tested fabric samples was expressed as a log reduction in which the mean log10 density of bacteria for the jar containing the test samples after 40


incubation over 1 or 24 hours was subtracted from the mean log10 density of bacteria for the jar prior to the addition of the test samples.

J E L1902:2002 Testingfor antibacterial activity and eflcacy on textile products" To investigate the antimicrobial properties of the test samples when exposed to bacteria by dry contact, an amended form of the printing method JIS L1902:2002 was used. The test was adapted so that a variety of heat and humidity conditions could be emulated, by conditioning the test samples printed with bacteria in desiccators at a set relative humidity and temperature. A range of contact periods was chosen. A 24 hour incubated test culture of S. aureus in nutrient broth was diluted with sterile nutrient broth to give a final concentration of 1-2 x lo5 CFU / ml. A sterilised 0.2 p membrane filter was placed in a Millipore filtration unit and 5 ml of sterile distilled water was poured on the filter followed by 2 ml of the diluted test inoculum. Filtration was carried out under reduced pressure (via a vacuum pump) and was maintained for 1 minute after the liquid had disappeared from the membrane filter. The membrane filter was then placed on the rotating table of the printing system with the bacteria coated surface facing uppermost. A test fabric sample, which had been cut into a circular swatch of 4.8 cm in diameter and autoclaved, was placed on top of the membrane filter. A silicone coated plate was placed on top of the fabric sample and a 4 N load was applied. Bacteria were printed onto the test fabric sample by rotating the rotating table by 180" in one direction over 3 seconds. The printed test fabric was removed for immediate shaking out in the case of the 0 hour sample or for incubation over different contact periods. For immediate shaking out, the printed fabric was laced into a glass jar containing 20 ml of sterilised water or appropriate neutraliserlg 13. The triclosan treated fabrics were neutralised using 30 g/l Tween 80 (polysorbate), while the QAC treated fabrics were neutralised using a mixture of 30 g/I Tween 80 and 3 gA lecithin. No neutraliser was used for the silver samples. The glass jar was then shaken using a vortex mixer 5 times for 5 seconds each. For incubation over different contact periods the printed fabric was placed in a desiccator conditioned to a temperature of 25 "C and a relative humidity of either 99% with a saturated solution of di-sodium hydrogen phosphate dodecahydrate or 10% with calcium chloride powder for 1 hour, 4 hours or 24 hours before shaking out. The relative humidity of the conditioned environment was monitored using an rH meter. After shaking out, serial dilutions were performed using sterile distilled water and plated onto nutrient agar plates using the Miles Msra method. The plates were incubated at 37 "C for 24 hours and the number of CFU present was recorded. All samples were tested in triplicate. The antimicrobial activity of the tested fabric samples was expressed as log reductions, calculated by two methods: 1) by subtracting the mean log10 density of bacteria recovered from the inoculated test samples at 1 , 4 or 24 hour contact time from the mean log10 density of bacteria of that test sample immediately after 0 hours contact time; 2) by subtracting the mean log10 density of bacteria recovered from the treated samples at each time point h m the mean log10 density of bacteria recovered from the control fabric at that time point.

RESULTS AND DISCUSSION The log reduction results for each of the fabrics when tested under moist conditions using AATCC 100 are shown in Table 2. Samples treated with QACs or triclosan showed a reduction in bacterial growth after both 6 hours and 24 hours. For the silver treated samples, a reduction in bacterial growth was observed for the samples which 0 Woodhead Publishing Limited, 201 0

41

were treated with silver as an &-treatment (finishes A and B), but no reduction in growth was observed for the inherent silver or silver coated thread samples. This should be expected, as silver requires the presence of an aqueous environment to readily ionise and become active'4*Is. If the silver is on the surface, as with the after-treated products, the silver should have sufficient contact with water to ionise and be effective; this is not the case for inherent silver roducts where the silver is trapped in the mtre of the fibre where it is not functional'. Although the triclosan sample tested is also inherent, a similar effect was not observed as triclosan migrates to the surface'. It should be noted that when the fabric containing silver coated thread was tested with the silver face down a slight reduction in bacterial growth occurred after 6 hours, but this was not observed when the sample was tested with the silver face up. After 24 hours there was an increase in bacterial growth with both the silver face up and the silver face down. This would suggest that after 6 hours there was sufkient moisture on the base of the container used to test the fabric for the silver to come into contact with it and ionise, but after 24 hours the moisture levels may have been too low for this to occur. The 100% bamboo showed a reduction in bacterial growth after 6 hours incubation, but no reduction in growth was seen after 24 hours. The 60% bamboo, 40% cotton blend showed an increase in bacterial growth. This suggests that there may have been insufficient bamboo fibre in the blend to have any antibacterial effect and supports previous claims that state that to be antimicrobial there must be greater than 65% bamboo content17. Carbonised bamboo on polyester showed no antimicrobial activity. The soy fibre showed only minimal antimicrobial activity after 6 hours. The unkated control samples all showed an increase in the number of organisms with 100% cotton having a larger increase in bacterial growth than 100% polyester. The higher the cotton content in cotton polyester blends, the higher the level of bacterial growth was recorded. This could be expected, as generally natural fibres are more susceptible to bacterial growth than synthetic fibres'*. This is due to natural fibres, like cotton, having higher level moisture retention than synthetic fibres like polye~ter'~. Bacteria prefer warm humid conditions to gmdp19, so higher moisture content in a fabric will encourage higher bacterial growth. Table 2. Log reduction results, calculated by comparison with time zero, for S. aureus using AATCC 100: 2004 on a range of fabrics Sample

Log reduction (standard deviation) 6 hours 24 hours

QAC* 67% polyester 133% cotton Triclosan 50% cotton I50% polyester Silver after-treatment finish A* Silver after-treatment finish B* Silver - inherent 50% polyester I50% cotton Silver coated thread / polyester both sides Silver coated thread / polyester single side: Face up Face down Bamboo (100%) Bamboo (60%)1 Cotton (40%) Carbonised bamboo/ polyester soy (1 00%) Cotton (100%) 42

0.80 (0.71) 0.68 (0.46) >1.38 0.54 (0.71) -2.93 (0.08) -0.98 (0.04) -1.29 (0.18) 0.08 (0.08) 1.84 (0.02) -0.93 (0.04) -2.72 (0.16) 0.30 (0.24)

---

1.66 (0.02) >1 .60t 1.33 (0.21) 0.51 (0.06) -3.935 (0.22) -2.55 (0.18) -1.70 (0.16) -1.68 (0.06) -0.33 (0.06) -2.17 (0.06) -2.75 (0.33) -2.75 (0.02) 4.58 (0.11)


Polyester (50%) / Cotton (50%) -2.83 (0.08) -3.83 (0.12) Polyester (67%) I Cotton (33%) -1.3 1 (0.08) -2.72 (0.33) Polyester (1 00%) -0.80 (0.28) -2.57 (0.10) *Quaternaryammonium salts. 'Decrease in bacterial numbers greater than the l i t of sensitivity. %O% cotton J 50% polyester. %crease in bacterial numbers.

To determine whether the inherent silver and silver coated thread samples would show antimicrobial activity when subjected to soaking wet conditions, the dynamic shake method, ASTM E2149, was performed. The log reduction results after 1 hour and 24 hours incubation at 37 "C (Table 3) show that under soaking wet conditions the inherent silver and silver coated thread samples do exhibit a reduction in bacterial growth. The untreated control samples show an increase in bacterial growth. From these results it would appear the antibacterial activity of inherent silver and silver coated thread samples require soaking wet conditions to exhibit their antibacterial properties. As with the AATCC 100 method, the carbonised bamboo sample showed no antimicrobial activity. Table 3. Log reduction results, calculated by comparison with starting inocdum for S. aureus using ASTM E2149-0 1 on a range of fabrics Sample

Log reduction (standard deviation) 1 hours 24 hours Polyester (1 00%) -0.41* (0.42) -2.53 (0.04) Polyester (50%) I Cotton (50%) -0.26 (0.02) -0.63 (0.16) Silver after-treatmentfinish A 100% polyester >1.91t 0.41 (0.03) Silver - inhmnt 50% polyester 150% cotton >1.92 0.79 (0.04) Silver coated thread / polyester (double sided) 0.56 (0.27) 1.26 (0.24) Silver coated thread / polyester (single sided) >1.91 0.91 (0.23) Carbonised bamboo1 polyester -0.09 (0.01) -3.98 (0.12) *negative figures indicate an increase in bacterial numbers. 'indicates a decrease in bacterial numbers greater than the limit of sensitivity of the test. The dry application of bacteria on treated and untreated fabric was tested using an amended form of the print method (JIS 1902:2002), so that environmental conditions such as relative humidity and temperature could be set and monitored. Initial work looked at 99% rH conditions with a temperature of 25 "C. These conditions were chosen as it was assumed that the treated samples would be more likely to show activity at a high relative humidity thus proving whether this was a feasible method to use. If treated fabrics showed activity in these conditions, lower relative humidities would be examined. The temperature was chosen to represent room temperature of the service environmentswhere these fabrics may be used. Results for the fabrics tested using the printed method were expressed as log reductions, initially these were calculated by subtracting the mean log10 density of bacteria recovered from the inoculated test samples at 1 , 4 or 24 hour contact time from the mean log10 density of bacteria on test samples after 0 hours contact time. The results for 99% rH and 25 "C test conditions using appropriate neutralisation (Table 4) showed log reductions in both the treated and untreated test fabrics. The reduction in bacterial numbers on the untreated fabric would suggest that there is some bacterial 0 Woodhead Publishing Limited, 2010

43

death by desiccation occurring. To establish the extent to which the reduction on the treated samples were due to the antibacterial finishes, the log redudion was calculated by subtracting the mean log10 density of bacteria recovered from the treated samples at each time point from the mean log10 density of bacteria recovered from the untreated control fabric at that time point (Table 5). The silver treated samples did not appear to have any significant effect on bacterial numbers, even though a neutraliser was not used. This would have led to an over estimation not an under estimation of any efficacy shown.The triclosan treated samples did not appear to have a significant effect on the bacterial numbers when neutralisation was employed. The results for the QAC on a 50% polyester 50% Cotton blended fabric showed a large standard deviation at 0 , l and 4 hours incubation but &er 24 hour a log reduction of greater than 1 was achieved consistently. The results for the QAC on a 67% polyester 33% cotton blended fabric did not appear to have a significant effect. Centrifugation of the cultures before printing did not adversely affect bacterial survival, as similar results for all samples tested were achieved wben the printing procedure was pedormed without centxifigation (data not shown). Removal of the neutralisation step did not improve the log reductions recorded for any of the samples, suggestingthat the antibacterial finishes were not being released into the resuspension solution (data not shown). This may be advantageous for some applications, as it points towards the durability of the finishes. Table 4. Log reduction results, calculated by comparisonwith time zero, for S. aureus using amended ns L-1902 using appropriate neutralisationa range of fabrics at 99% rH Log reduction (standard deviation) Sample lhr 4hr 24hr QAC* 67% polyester 133% cotton 1.65 (1.63) 0.45 (0.40) 1.37 (2.74) QAC SOYOpolyester I 50% cotton 1.46 (1.45) 0.40 (1.82) 2.18 (2.63) Triclosan 50% cotton I 5oOh polyester 0.45 (0.68) 0.52 (0.05) 1.10 (0.30) silver after-treatmentfinish A+ 0.44 (0.36) 1.19 (1.21) 2.24 (0.67) Silver after-treatmentfinish Bt 1.22 (1.16) 0.82 (0.52) 2.10 (0.51) 67% polyester I 33% cotton 1.33 (1.79) 0.26 (0.24) 1.74 (2.20) 500?polyester I 50% cotton A 0.70 (0.17) 0.52 (1.02) 1.60 (0.87) W ?polyester I 50% cotton B 0.86 (0.92) 0.72 (0.38) 1.37 (1.16) Quaternary ammonium d t . 'neutralisation not used, 50% cotton I 50% polyester. Table 5. Log Reduction results, calculated by comparison with the control, for S. aureus using amended JIS L-1902 using appropriate neutralisationa range of fabrics at 99?hrH Sample Log reduction (standard deviation) Oh lhr 4hr 24hr QAC* 67% polyester I 33% 0.12 (0.1 1) 0.43 (0.53) 0.3 1 (0.27) -0.26T(0.92) cotton QAC 50?hpolyester I 50.41 0.64 (2.04) lAO(O.98) 0.52(0.81) 1.22(0.29) Cotton

0.03 (0.40) -0.38 (0.52) -0.17 (0.29) -0.23 (0.11) Triclosan 500h cotton I 50% polyester Silver after-treatment finishA* -0.78 (0.46) -1.04 (0.28) -0.12 (1.02) -0.14 (0.54) Silver after-treatmentfinish B* -0.23 (0.89) 0.29 (1.30) 0.06 (1.82) 0.27 (0.14) *Quaternary ammoniumsalt. 'Negative figures indicate an increase in bacterial numbers in comparison to the control at that time point. *Neutralisationnot used, 50% cotton I 50% polyester. 44


Control experiments were conducted in duplicate to investigate the survival of S. aureus at high, loo%, and low, Nonwoven fkbric

/

'

type (e.g. Aor B)

Figure 1: Layers of absorbent core

Table 1:Details of sandwiched absorbent cores Sample No. A1

A2 A3 A4

A5 A6 A7 A8 A9 B1 B2 B3

B4 B5 B6 B7 B8 B9

Nonwoven fabrics b e Mess

_. A A A A A A A

A A B B B B B B

B B

B

g/m2 20 20 20 20 20 20 20 20 20 60 60 60 60 60 60 60 60 60

Blended web details SAF % 10 30 50 10 30 50 10 30 50 10

30 50 10 30 50 10 30 50

Sandwichedcore details

Viscose

SAF

Totalmass

Y O

g/m2

%

%

g/m2

90 70 50 90 70 50 90 70 50 90 70 50 90 70 50 90 70 50

60

94 82 70 93.3 80 66.6 92.8 78.6 64.3 96.6

6 18 30 6.7 20 33.4

100 100 100 120 120 120 140

Viscose Totalmass 60

60 80 80 80 100

100 100 60 60 60 80 80

80 100 100 100

90 83.3 96 88 80 95.5 86.4 77.3

7.2 21.4 35.7 3.4 10 16.7 4 12 20 4.5 13.6 22.1

140

140 180 180 180 200 200 200 220 220 220

determined by immersing it in physiological saline (0.9% saline) for 30 minutes and then draining it for 30 minutes. The difference between the mass (g) after drainage and the mass (g) before immersion was taken as a saturation absorption. The time taken by the napkins to completely absorb 5 ml of 0.9% salt solution (i.e. absorption time) was measured according to the previously used ASTM standard D 824-94.

Figure 2: Cross sectional view of control sample

Figure 3: Cross sectional view of developed absorbent core

150 0 Woodhead Publishing Limited, 201 0

Figure 4: Cross sectional view of napkin with developed absorbent core

RESULTS AND DISCUSSIONS Thicknessof dserent samples In a sanitary napkin, along with the mass per unit area and absorbency, the thickness is also very important characteristics. A thicker napkin is not at all desirable. The thickness values of the developed samples and the control sample are given in Table 2. For samples of both types A and B, we noticed a significant increase in thickness with an increase in the mass of blended web portion of the absorbent core. It is evident from the Table 2 that the thickness of the prepared samples is significantly lower, in most cases (Al-A9, and Bl-B3), compared to the control sample, which would be an added advetage for an ultra-thin sanitary napkin. It has also been observed that a change in content of SAF in the web does not affect the thickness of the sample significantly. So, the mean thicknesses for the same mass of sandwiched core samples have been reported.

Horizontalwicking The horizontal transport rate of transporting layer of control sample (layer 2) and the two types of nonwoven fabrics is given in Table 3. From the Table 3, it is observer that as fabrics A and B are made of viscose, which being absorbent in nature, give wide variation in wicking time depending on fibre alignment and mass per unit area. The parallel laid sample A, gives shorter time along the direction of the laid fibres whereas the random laid sample B, takes relatively higher time of wicking and approximately equal times in both directions. The higher time for travel in case of sample type B is mainly due to higher mass per unit area, where absorption is dominant and takes longer time for horizontal travel. The control sample shows wide difference in wicking characteristicsbetween X and Y directions. Table 2: Mean thickness of samples Sample Control sample A1 -A3 A4 - A6 A7 - A9

Meanthickness, mm 2.91 2.54 2.73 2.82

Sample

Meanthickness, mm

B1 -B3 B4-B6 B7 - B9

2.67 2.97 3.12

Table 3: Horizontal transport rate of samples SamDle

Laver

Volume ( A

Time (set)

xaxis Control sample

Layer 2

so

Fabric A Fabric B

--

50 50

_-


44.4 7.06 14.02

Yexis 2.02 3.23 16.98

Controlsample

Wicking height (cm)

FabricTypeA

2 1

-

-- -------C-----'-~

,,---z-

FabrictypeB

c

0.5

0

5

0

0

15

10

Time (min)

Figure 5: Vertical wicking heights of control sample and nonwoven fabrics

Vertical wicking The vertical wicking characteristicsof transporting layer of control sample (layer 2) and the two types of nonwoven fabrics (TypeA and Type B) are given in Fig. 5. Capillary action is governed by the properties of the liquid, the fibre surface wetting characteristics,and the geometric configurationsof the porous medium Both fabrics A and B give comparable rates of vertical wicking with that of layer 2 of the control sample, though the random-laid sample B gives slightly higher rate than the parallel-laid one. This may be because of the differencein their mass per unit area.

'.

Glass tube wicking Fig. 6 shows the comparative glass tube wicking results of different developed sandwiched samples h m different blend proportions of web with 60 g/mz mass of web and the control sample. From the graphs plotted for the samples A and B types nonwoven fabrics (Fig. 6); we notice that with the increase in the SAF % of the web portion of the absorbent core, the rate of transport of the salt solution in the vertical direction increases (rate is measured by gravimetric method). This may be due to the much greater tendency of SAF to absorb the fluid compared to viscose fibre, even though there would not be a significant increase in the number of capillaries as the web mass remains unchanged. It can be seen that this general trend holds for both the fabric types and increasing mass per unit area of web, barring a few points of discrepancy. Figs. 7 and 8 show the similar trend for web mass of 80 glm' and 100 glm' respectively. O

I

h Tub. Wkkhg

1W

280

I:

ea

I

s o 0

50

100

150

ZM

Tbm (In uo)

Figure6:Glass tube Wicking comparison for 60 g/mz web mass


I

I

Glus Tube Wcklng

0

50

100

150

200

250 I-Cli.JhalI

Time (In me)

Figure 7: Glass tube wicking comparison for 80 g/mz web mass Gk8s Tube Wlcking

Figure 8: Glass tube wicking comparison 100 g/mz web mass On comparing the rates of transport by samples having different web mass per unit area (g/mz) but same SAF %, no significant change is observed. This may be due to the very nature of the test, as the glass tube used for the tests is the same. This caused the amount of sample inserted into the tube to be nearly the same and hence a change in g/mz would not affect the relative rates. On comparing the developed samples with the original control sample, it is observed that B8 and B9 give better results in this test than the standard sample. These are made using random laid fabric in combination with a high SAF %. Samples B1, B2, B3, B7, A8 and A9 are comparable though slightly less than that of the control sample. Therefore, it is clear that on an average, the developed samples are comparable in performance in the Glass Tube Wicking test, as shown above.

Absorption time The time taken to absorb 5 ml of 0.9% salt solution by the napkin samples, i.e. absorption time, for aLl the developed absorbent core samples along with the control sample is given in Table 4. From this test, there are three important things to be noted. Firstly, it is clear that with an increase in g/mz of web portion of the absorbent core, the time taken by the samples to absorb 5 ml of 0.9% saline decreases significantly. Secondly, all the developed samples give an absorption time which is significantly lower than that of the control sample. Thirdly, the samples having the absorbent core containing the fabric of type B give signifcantly lower absorption times compared to those having fabric type A. This can also be inferred as fabric B gives higher vertical wickiflg rate than fabric A, as can be seen fiom F i g 5 Moreover, these tests have been


Table 4: Absorption time developed and control samples Sample

Time

Sample

Sec

Control A1 A2

A3 A4

13.11 11.02 10.89 10.96 10.38

Time

Sample

SeC

A5 A6 A7 A8 A9

10.30 10.34 9.76 9.84 9.70

B1 B2 B3 B4 B5

Time sec 9.32 9.36 9.20 9.01 8.90

Sample

B6 B7 B8 B9

Time(=)

8.92 8.64 8.61 8.68

performed without the presence of a polypropylene distribution layer of the control sample thereby showing that the function of distribution of the fluid is being performed by the absorbent core itself. This not only demonstrates the superior performance of the developed sample but may also help in reducing the cost and thickness by eliminating an entire layer from the napkin. In practice, surfactants are often used to promote spreading of liquids on the surface of solids7. No definite trends were observed when the SAF % was increased.

Saturation absorption Saturation absorption for 0.9% saline solution of developed and control samples are shown in Fig. 9. It is clear from Fig. 9 that the saturation absorption increases with the increase in the proportion of SAF, due to obvious reason. Also, the type A samples show higher saturation absorption values than the type B samples. This is due to effective proportion of SAF in the type B samples are lower than correspondingtype A samples. As the saluration absorption is dependent on both overall proportion of SAF and mass per unit area of the core, it was tried to get the relationship between these parameters..The idea of getting the relationship was to predict the required saturation absorption and accordingly select the proportion of S A F and mass of sandwiched web. The least squaring technique was adopted for this and the relationship was found to be straight line. The relationship with the existing experimental data was found to be;

are the SAF?? and g/m2 of the overall sandwiched web. Hence, one can predict the absorption capacity of the absorbent cores prepared by present method, for any known values of total g/m2 of the core and the SAF %. This will help to optimize the amount of SAF needed and the g/m2 of the absorbent core according to the desired performance. where, Y is saturation absorption and XIand X2


s

50

B1

B9

Sample

Figure 9: Saturation absorption developed and control samples

CONCLUSIONS The prepared napkin samples were mostly thinner or equivalent to the control sample. They showed significantly better rates of absorption for saline solution even though the glass tube wicking (gravimetric) test gave only comparable results. The saturation absorption of the core also follows a linear relationship, dependent on two variables, namely the mass per unit area and proportion of SAF. This w ill help to predict and optimize the absorption capacity of the core according to the desired performance. So, the present research has, therefore, indicates that the napkins performance can be enhanced by the use of blends of super absorbent fibre with some other relatively cheaper fibres.

REFERENCES 1 ASTM No. D 824 - 94: Standard Test Method for Rate of Absorption of Water by Bibulous Papers 1. 2 ASTM No. D 2177-99: Standard Test Method for Ink Absorption of Blotting Paper.

4 UMIST Wettability tester manual.

5 Technical Report 17: Chelsea centre for recycling and economic development, University of Massachusetts,April 2000.

6 R M Crow and R J Osczevski, ‘The interaction of water with fabrics’ Text Res J, 1998,68(4) 280-288.

7 K Slater, ‘Comfortproperties of textiles’, TextiZe Progress, 1977,9(4) 15.


RETENTION OF ANIONIC SURFACTANT FOLLOWING GARMENT LAUNDERING AND ITS POTENTIAL EFFECT ON DERMATITIS SUFFERERS H D Rowe Manchester Metropolitan University, Manchester, UK ABSTRACT There are many causes of skin disorders and different forms from which a subject may suffer. initant Contact Dermatitis (ICD), an inflammatory condition caused when the skin comes into contact with various agents and Allergic Contact Dermatitis (ACD) which occurs when the body becomes sensitized to particular products are two conditions that can make the life of the sufferer a misery. The domestic detergent industry in the UK is vast. Although constituents vary from product to product the 'cleaning' component will, in general, be a surfactant of either anionic or non-ionic nature. It is known that at high enough concentrations surfactants are able to muse dermatitis but this is usually within industrial cleaning scenarios. Nevertheless the fabrics that our clothes are made from are often attractive to the chemical components of detergents and if insufKcientlyremoved from the fabric interstices when rinsed, may remain within the fabric structure and increase to potentially dangerous concentrations. This paper discusses the links between clothing, the skin and domestic detergents, describes a method developed to determine the retention pattern of anionic surfactants over progressive washes and finally presents results of tests conducted on cotton and polyester materials. Analysis of results shows cotton to retain more anionic surfactant to polyester at all concentrationsand all wash levels.

INTRODUCTION Dermatitis (also referred to as eczema) is a skin condition which affects a large proportion of the population at some time in their life. The British Skin Foundation's website contains the strap line; '8 million people in the UK suffer from some form of skin disease' (British Skin Foundation, 2006)'. contact Dermatitis which can be either irritant (ICD) or allergic (ACD) in nature are two afflictions for which detergents are sometimes blamed. Kremer et al. (2000)' agree that the number of sufferers of skin conditions is increasing and that the blame is often put on detergents. Bauer et al. (2003Q state categorically that 'ICD is an inflammatory response of the skin after contact to various irritant factors, such as detergents As soon as a skin reaction is brought to the attention of a doctor probably one of the first things they will ask is "haveyou changed your washingpowder? (Natiod Eczema Society, 2003)4. Those who work in wet conditions or spend fiequent amounts of time using cleaning fluids are certainly at risk and a considerable amount of work time can be lost due to occupational exposure to detergents (Wigger-Alberti et al., 2OOO)*. But will the detergent components remaining within our clothes after laundering have similar effects? The main cleaning agent in a typical home laundry detergent is the surfactant which in most domestic products will be either anionic or non-ionic in nature. Surfwtants lower the surface tension of water allowing the fabric surface to be wetted out and assist ....I

If


in loosening the soil, Builders are included to help soften water and prevent soil being redeposited on the fabric after release. OrigLnally phosphate based, these are increasingly being replaced by zeolites. Biological @io) detergents contain enzymes to help digest protein, fat and starch based stains. Sometimes bleaches are added to remove coloured stains but are not necessitated or desired for washing coloured garments. Finally there are a number of additional constituents that may be present such as foam regulators, optical brightening agents and perfumes. There is massive choice for the consumer not only in the case of bio versus non-bio but also in the form that the detergent takes: powder-; liquid; tablet; gel. Although some consumers favour non-bio products over biological (assuming that it is the enzymes that cause dermatologicalproblems), several researchers have disputed this (Jakobi and Lohr pp 190-194, 19876;Anderson et al., 1998)'. In the case of surfactants, Matthies (2003, ~ 1 2 4 admits )~ that irritancy against surfactants is a common phenomenon at threshold concentrations. Surfactants are known to impair barrier function of the skin and induce irritation. Once adsorbed onto the skin the surfactant emulsifies the lipids on the skin surface leading to a rough, scaly, dry surface (Ale et al., 1997)9.However Jakobi and Lohr (1987) and Porter (1994)" insist that the levels of surfactants used in domestic detergents are safe. There is clearly some disagreementamongst researchers. The retention of surfactants on clothing may pose problems not previously suspected. Kremer et al. (2000) and Bircher (p168,2003)' suggest that detergent residues are not completely removed from fibres on rinsing. The reasons for this will be due to washtrinse process and also to the complexity of the fabric substrates that detergents find themselves applied to. Fibre content, yam structure, fabric construction, dyeing, printing, mechanical and chemical finishing processes can all affect the way aqueous solutions of detergents will attach themselves to clothing. Whilst the results of some research on detergent and clothing substrates is reported (Kurz, 200312 ;Matthies, 2003) the author believes that not until quite recently has the effect of fibrelfabric composition been considered as a contributing factor to dermatitis. Frequently the advice given to eczema sufferers is to wear cotton clothing (British Skin Foundation, 2006) but to quote Wffliams (2001)'3 in his review of treatments of atopic eczema "there was no evidence to support any clear clinical benefit on the use o j . .cotton clothing as opposed to soft-weave synthetics... . . The experimental work that follows tends to agree. I'

EXPERIMENTAL For the experimental part of this study it was decided to concentrate on the retention of anionic surfactant on fabrics used in clothing. The most popular fibre types for apparel wear are the natural cellulosic fibre, cotton and the synthetic polymer, polyester. Often these two are combined together by blending in various proportions, the blend percentage depending on the intended enduse (Rowe, 2006)14. However to simplify the evaluation in this initial study it was felt necessary to use 100 % cotton and 100 % polyester fabrics. As mentioned previously, fabric constructions vary considerably and so it was important to select fabrics as similar as possible in weight and construction so that the evaluation could be concentrated on the effect of fibre type only. Fabrics were sourced from a local manufacturer, in greystatc. Each was plain woven, approximately 140 g/mz area density with 30 x 30 warp and weft threads per cm. The assurity of the greystate of the fabrics meant that neither had been subjected to dyeing, printing or chemical finishing processes which might affect retention levels. However it was clear that they may still 0 Woodhead Publishing Limited, 201 0 157

contain remnants of spinning oils and other auxilliary spinning I weaving products which necessitated the fabrics being thoroughly scoured prior to testing. it was found during the course of preparing the test regime that scouring the fabrics prior to testing reduced the presence of pre-existing anionic surfactant by over 75 %. In order to simulate the concentration of anionic surfactant present in a normal wash load advice from washing powder manufacturers was sought. Simply by reading consumer information on the side of packs it was found that for a normal wash lOOg of product (containing between 5 - 15 % anionic surfactant) should be used. Calculations were made in order to determine the levels of concentrationsneeded for this bench scale laboratory evaluation and it was found that subjectingthe 2 fabrics to wash cycles with 0.2 g/L; 0.4 g/I, ;0.6 g/I, of surfactant would cover the same range that a garment might encounter in normal domestic washing. Granular laboratory standard anionic surfactant was used for this purpose. No other detergent component was added. Preliminary tests using a standard Wascator washing machine for the wash cycles showed that results could be affected because of contamination of the drum and pipes etc by remnants of surfactant from p v i o u s launderings. It was therefore decide to conduct wash cycles in a bench scale Gyrowash machine which enabled thorough cleaning to take place between wash loads. A 40 * C main wash followed by 5 x cold, distilled water rinses was adopted. Wash cycles were repeated up to 5 x on all samples and all samples hung to dry after each cycle. All sizes / weights of fabric, liquor capacities , surfactant concentrations etc were scaled down appropriately to best simulate standard washing practices. Following each wash cycle it was necessary to extract the retained surfactant from the fabric. This was done by boiling with distilled water for 30 minutes in a water cooled soxhlet extractor. The product of this extraction was then divided into several samples for repeat testing and each subjected to measurement of anionic surfactant content using a HACH Colorimeter . This preparation process required 300 mls of the sample under test to be introduced to a separatory funnel together with 10 mls of buffer solution, the contents of one detergent reagent pillow and 30 m l s of benzene. The contents were mixed by gently shaking and then allowed to separate over a period of 30 minutes. After this time the lower, aqueous layer was discarded and the top benzene layer transferred to a phial and placed in the colorirneter for measurement. To recap, the experimental work included : J J

J J J

J

Selecting 2 similar greystate woven fabrics in 100 % cotton and 100 % polyester. Subjectinggreystate fabric to pre-washing Washing fabric in a controlled environment using 3 concentrations of anionic surfactant, one wash temperature and progressive wash cycles. Subjecting samples of each to an extraction process using a soxhlet extractor Subjecting the resultant liquor to a strict preparation for measurement process by associating the anionic surfactant component with crystal violet dye and extracting the ion-pair complex into benzene. Subjecting the benzene layer to colormetric analysis using a portable HACH colorimeter


RESULTS

Table 1 Average amount of anionic surfactant extracted from washed cotton fabric in mg/L

Concentmtipn of anionk surfbetant added to wash cycle in g/L 0.2 0.4 0.6 Wash I Wash 2 Wash 3 Wash 4 Wash 5 - __

0.38 0.56 0.63 0.89 I .09

0.75 0.84 0 75 0.9 I

0.73 1.16 1.09 I .09 I -.36 -.

1.13

-

Table 2 Average amount of anionic surfactant extracted from washed polyester fabric in mgil. ______

___

Wash I Wash 2 Wash 3 Wash 4 Wash -- .5

[-test

-

Concentration of anionic surfactant added to wash cycle in g/L 0.2 0.4 0.6 0.25 0.3 1 0.35 0.28 0.24 0.24 0.23 0.24 0.25 0.38 0.46 0.3 1 0.29 0.2 I 0.39 _ _ ~ _ _ . __ ~

~

Table 3 signiticance of difference between results of wash I and wash 5 at each anionic concentration level in wash cycles for both cotton and polyester fabrics

conc. of anionic surfactant in wash cycle 0.2 0.4 - 0.6

t-value and indication of significance of difference between results of Wash 1 and 5 in both fabrics Cotton Polyester t-value sig t-value Sig 8.02 4.35 5.42

*** ** **


2.10 0.50 3.20--

*

-

Table 4 t-test significanceof difference between results of cotton and polyester fabrics at 3 levels of anionic concentration and over 5 wash cycles key : - no significance ; * sig difference ;** highly sig diff; *** very highly sig diff

Wash cycle

number__

t-value and indication of simificance of d i f f i n c e between results for cotton and paly&r at each amcentration level (&I,)

0.2 [-value

1.46 6.40 3.57 6.90 10.96 .___ -

d

0.4

sig

**

* **

***

t-value

4.35 5.9 I 6.40 1.57 45.4

-

0.6 sig

**

** **

***

t -va I ue

9.92 6.2 1 6.64 9.53 9.76

sig *** ** ** *** ***

-

l m I L R n

...

Retained anion i surfactant in cotton an2 polyester fabrics over progressive washes

DISCUSSION Tables 1 and 2 show the amount of anionic surfactant removed from the cotton and polyester fabrics using soxhlet extraction methods subsequent to a normal wash and rinse process. It is assumed that had the detected anionic surfactant not been forcibly extracted from the fabrics at least this amount would still be retained within the material following domestic washing. Immediately it is clear that even at the lowest concentration (0.2 g L ) the cotton fabric has released (and therefore is assumed to 160 0 Woodhead Publishing Limited, 2010

normally retain) 2 to 3 times the surfactant content than the polyester fabric. At the higher applied concentration (0.6 g/L) this rises to around five times as much. Considering the effect of increasing initial concentration of anionic surfactant on the cotton fabric (Table l), the retention appears to consistently increase both as concentration of anionic surfactant increases and as number of washes increases. The difference between the first wash and fifth wash has been statistically tested for significance using a 2 tailed t-test. This has been repeated for each anionic surfactant concentration level. The t-value results and an indication of their significance can be seen in Table 3. Turning attention to the polyester fabric results (Table 2). Despite the increase in initial anionic surfactant concentration levels, and the repeated wash cycles, the amount of anionic surfactant released from (and therefore assumed to be normally retained within) the polyester fabric, after extraction, remains fairly consistent, hovering around the 0.3 mgL level. Again the statistical significance of the differences between wash 1 and 5 at each concentration can be seen via t-test results in Table 3. This shows us that increasing the number of wash cycles increases the amount of retained surfactant to a highly significant, if not very highly significant degree in the case of cotton but only shows some degree of significanceat the 0.6 g/L level for the polyester fabric. To determine whether there is a real difference in the retained anionic surfactant between cotton and polyester at all initial anionic surfactant concentrations and across all 5 washes, significance test results are reported in Table 4. This indicates that there is a highly significant difference between the retained anionic surfactant levels of cotton and polyester both at the higher initial concentration (0.6g/L)level and at the higher wash cycle ( 5 ) level, with cotton retaining the most. Figure 1 illustrates the obvious difference in retention levels between the two fabric types. The gross morphological structure, fine structure and chemical composition of cotton suggests that applications from aqueous solutions will readily be attracted to the fibre, often becoming chemically attached (as in the case of some dyes and finishes) but in any case readily being absorbed into the amorphous areas of the fibre and particulates, especially, are able to be trapped within the convoluted outer structure of the fibre. For the same reasons that cotton readily lends itself to such invasion, polyester's gross morphological, fine and chemical structures do not. Relatively simple, linear molecular chains give rise to regions of high crystallinity (and therefore strength) ; molecules consisting of chemical sites relatively unattractive to moisture (long well understood because of its inability to dye without some assistance from high temperature and pressure) and a smooth, featureless outer structure (easily observed using optical microscopes), means that, before seeing the results presented here, it could have been postulated that cotton would retain the most. What is of especial interest is that after the initial take up by polyester neither increasing concentration nor increasing number of wash cycles appears to encourage further take up. Indeed the fibre appears saturated, unable to accept any more anionic surfactant, which could be good news for those who suffer dermatologicalproblems as a result of surfactant contact. This research is in its initial stages. Now that a test regime has been developed and tested what will be interesting to see next is whether altering fabric strucme (using knit as opposed to woven fabric) shows up any anomalies. It is also important to see what effects other fibre types have on the results. Would other synthetics behave in a similar manner to polyester and would say viscose, a manmade fibre but with a cellulosic 0 Woodhead Publishing Limited, 201 0 161

chemical composition, behave like cotton? It is hoped that results of tests on these other materials will be available within the next 12 months. Qualitative research is also important to this study. The researcher intends to gather information from dermatitis sufferers to determine what fabric choices they make and what washing habits they adopt. Interviews with Dermatologists will be sought in order to gather evidence of the advice they give to patients on what fabrics they should wear and laundry products they should favour. Eventually it is hoped to propose the ideal fabric/ launderingprocesses to reduce the effect of detergents on dermatitis sufferers.

CONCLUSIONS Some forms of contact dermatitis are exacerbated by fabric detergents. The dermatitis sufferer is confronted with a massive choice of both apparel fabrics and washing detergents to choose from.If detergents are preferentially absorbed into particular fibre types or inefficiently rinsed from them harmll residues may re& Tests have been conducted on cotton and polyester fabrics to determine the retention levels of the anionic surfactant component of detergentsat 3 levels of concentrationand over a series of wash cycles. It has been found that the cotton fabric retained up to five times as much surfactant as polyester. Polyester appears to become saturated with surfactant at low levels and is unable to retain M e r amounts. This information could form the basis of preferred fabric choices for dermatitis sufferers. The research will continue with a survey of buying and washing habits of dermatitis patients and further laboratory work on a range of fibre types and fabric constructions

REFERENCES 1 British Skin Foundation 2006. http:llwww.britishskinfoundation.org.uWabout/eczema-overview.asp accessed 19.09.2006

2 J bemer, W Matthies, & I Voigtmann, ‘New perspectives on skincompatible detergents for sensitive-skin’ Tenside Surfactants Detergents, 2000 37(6) 350 -356.

3 A Bauer, J Bong, P J Coenraads, P Elsner, J English, H C Williams, 2003 ‘Interventionsfor preventing occupational irritant hand dermatitis’.(protocol). Cochrane Dutabuse of Systematic Reviews 2003, Issue 3 . Art. No. : CD004414. DOI: 10.1002/1465 1858.CD004414. 4 National Eczema Society 2003 ‘Factsheet- Washing Products and Fabric Softeners’ Nov 2003, London :National Eczema Society.

5 W Wigger-Alberti, A Krebs, P Elsner, ‘Experimental irritant contact dermatitis due to cumulative epicutaneous exposure to sodium lauryl sulphate and toluene : single & concurrent application’ British Journal of Dermatology, 2000 143 55 1-556. 6 G Jakobi, & A h h r , Detergents and Textile Washing - Principles & Practice VCH Publishers, Cambridge 1987.


7 P H Anderson, C Bindslev-Jenson, H Mosbech, H Zachariae, K E Anderson, ‘Skin symptoms in patients with atopic dermatitis using enzyme-containing detergents’ Acta Dermato-Venereologica, April 1998 78 1 60-63. 8 W Matthies, ‘Irritant dermatitis to detergents in textiles’ pp 123-138 in Textiles and the Skin, P Elsner, K Hatch and W Wigger-Alberti,( Vol.Eds), in Current Problems in Dermatology, vol3 1, Burg, G. (Series Ed), Basel : Karger. 9 S I Ale, J-P K Laugier and H I Maibach, ‘Differential irritant skin responses to tandem application of topical retinoic acid and sodium lauryl sulphate : 11, Effect of time between first and second exposure’ British Journal of Dermatology, 1997 137 226-233. 10 M R Porter, Handbook of Surfactants 2”* ed Glasgow: Blackie Academic & Professional 1994.

1 1 A J Bircher, ‘Cutaneous immediate-type reactions to textiles’ 166170 in Textiles and the Skin, P Elsner, K Hatch, and W Wigger-Alberti, (VoLEds), in Current Problems in Dermatology, 31 G Burg, (Series Ed), Basel :Karger, 2003. 12 J Kun, ‘Laundering in the prevention of skin infections’ 64 -81 in Textiles and the Skin, P Elsner, K Hatch, and W Wigger-Alberti, (Vol.Eds), in Current Problems in Dermatology, 31 G Burg, (Series Ed), Basel : Karger 2003. 13 H Williams, 2001 ‘Systematicreview of treatments of atopic eczema.’ The Research Findings Register. Summary number 468. Retrieved 19 September 2006 f?om

http:l/www.ReFeR.nhs.uk;NiewRecord.asp?ID=468. 14 H D Rowe, ‘Detergents, clothing and the consumer with sensitive skin’International Journal of Consumer Studies, 2006 30 369-377.


PREPARATION OF PROTECTIVE DISPOSABLE HYGIENE FABRICS FOR MEDICAL APPLICATIONS M. Montazer’, F. -chi2,

F. Siavoshi3

’ Department of Textile Engineering, Amirkabir University of Technology, Tehran, IRAN * South branch of TehranAzad University, Tehran, IRAN

Deptertment of Science, Tehran University, Tehran, IRAN

ABSTRACT One way for disease transmission from one person to another is using clothes by different people in hospitals. Using of the disposable clothing products with antimicrobial finishing can provide a good protection against transmission of diseases for both the surgery team and the patients. When it comes to the medical market, nonwovens are exactly what the “doctor ordered”. Both manufacturers and consumers are already awam of the many benefits nonwovens offer to the medical market. When compared to textiles, nonwovens are lower in cost, easier to use, more versatile, safer and feature better disposability. With this in mind, it is no wonder that nonwovens are found in hospital surgical drapes and gowns, protective face masks, gloves, surgical packs and bedding and linens. In this research, cetyl trimethyl ammonium bromide (CTAB), as an antimicrobial agent is applied on polyester, polypropylene and viscose non-woven fabrics alone and in combination with a Fluorochemical (FC 1112). The antimicrobial, water and blood repellency of the treated samples were investigated. To reveal the antimicrobial properties of the treated samples, the zone of inhibition and reduction of bacteria were measured with S. aureus, E. coli and P. aeroginosa. The results showed a good antimicrobial property on different concentration of CTAB solutions (l%, 2%, 4% and 8%). Application of CTAB with concentration of (O.S%, 1% and 2%) on polyester, polypropylene and viscose nonwoven fabrics indicated a reasonable antimicrobial effect. Co-application of CTAB with fluorochemical on different samples also showed a good antimicrobial,water and blood repellency properties.

INTRODUCTION Textile goods are excellent substrate for growing microorganisms. For the last fifty years, the prevention of microbial attack on textile materials has become increasingly important to consumers and textile producers [l]. Clothing such as socks and underwear faced with odor €rom body perspiration. Currently there is also an interest in protecting health care workers from diseases that might be carried out by patients. Especially for surgical gowns, there is an increasing need to protect medical staff from infection by blood borne pathogens such as M V and HBV. Gowns should be able to prevent stricke through or wetting out of the fabric, and so surgical gown materials should not only have antimicrobial properties but also blood barrier properties [2]. In addition the textile wed in hotels, transportation and biological institutionneeds antimicrobialtextiles [A. Nowadays nonwoven fabrics are the most commonly used textiles for surgical gowns, patient drapes, laboratory coats, coveralls, and other kinds of protective clothing [S]. Moylan et al, in a study of 2181 clean and clean-contaminated general surgical operations, showed that there was a significantreduction in the post-operative infection rate in both categories of operations when a disposable gown and drape system was 164 0 Woodhead Publishing Limited, 2010

used compared with a cotton system. The risk of developing a wound infection was 2.5 times greater with the cotton system than with the disposable system [l 11. Polyethylene terephethalate is a preferred textile fiber in many durable applications of nonwoven for its ease of use and compatibility with other fibers. Although Polyester has excellent mechanical strength and good stability but its end use capacity is limited due to the difficulties associated to functional finishing i.e. lack of polar groups on the surface and poor wet ability [9]. Fluorochemid are mostly used as repellent agents in textile finishing, which satisfy the demand for high water repellency and also impart oil and soil repellency to textiles 161Different antimicrobial agents have been applied to obtain antimicrobial properties to textile [3]. Among them, the quaternary ammonium salts of cationic surfactants are widely used in antimicrobial finishing of textiles [4]. Quaternary ammonium salts exhibit marked antimicrobial activity against a wide range of bacteria, fungi, and viruses [lo]. In this study cetyltrimethyl ammonium bromide (CTAB) was used as an antimicrobial agents. This agent has been frequently used in textile dyeing and finishing as either softener and leveling agents or as disinfectants, but has not been employed as an antimicrobial agent on nonwoven fabrics [8].

EXPERIMENTAL The polypropylene and polyester melt blown and raw and dyed (direct) viscose nonwoven fabrics, cetyl trimethyl ammonium bromide (CTAB) as an antimicrobial finish agent (Fig.l), citric acid (5%), and fluorochemical namely FC 1112 (Organic Kimia Co.) as a water and blood repellents were used. 0r-

'343

H~C(CH~~,~AJ+N~ AH3 Figure 1- Chemical structure of cetyl trimethyl ammonium bromide

To prepare the antimicrobial finish, the samples were padded through baths of 0.5, 1 and 2% CTAB solution with wet pick up of 130%, dried at 80 - 85' c for 3 minutes and cured at 145-15O'c for 3 minutes. We also used both the fluorochemical repellent and the antimicrobial agent in one bath. The antimicrobial properties of samples were evaluated quantitatively by measuring the reduction rate in the number of colonies and qualitativelyby showing a clear zone of inhibition around the samples. In order to evaluate the antimicrobial properties of the samples, three common pathogen bacteria were used including: Staphylococuse aureus (gram positive), Escherichia coli (gram negative) and Pseudomonas aeroginosa (gram negative). The reduction rate of bacteria growth under agar plates was calculated by the following equation: R %=( A-B)/Ax 100 Where A is the number of bacteria colonies fiom an untreated fabric, and B is the number of bacteria colonies from the treated fabric. The water and blood drop absorption was measured by the time of absorption of the droplet on the fabric surface.


Results and discussion The antimicrobialand fluorochemical finshes used in this study were mixed in a single bath and could be applied to nonwoven fabrics to impart the desired properties. The results of antimicrobial activities of polyester and polypropylene treated fabric with different bacteria are indicated in Tables 1-5. The inoculum was a nutrient broth culture containing 0 . 5 1~06, 1x 1O6 and 1.5 x 10 6 / d colony-formingunits (CFU) of the bacterium. The results show that 1% and higher concentration of CTAB on both polyester and polypropylene fabrics reasonably inhibit the growth of E. coli at pH=7 and S. aureus and P. aeroginosa at pH=5.5 (pH=5.5 is the pH of body skin). This test can not be used for viscose nonwoven because of disturbing effect of adhesive used for fabric production. The zone of inhibition also observed for each sample. The results are shown in Table 6, the sign (+) represented for the sample with formation of zone of inhibition and the sign (-) for the sample without formation of zone of inhibition. The results show a clear zone of inhibition around the treated samples with different concentration of CTAB. It was noted that an increase in CTAB concentration leads to an increase in the zone of inhibition reflected by enlargement of the diameter of zone of inhibition. It was also found that the effectivenessof the antimicrobid finish of CTAB can not be influenced by the level of the fluorochemical finish. Table 1. Antimicrobial activity of polyester and polypropylene fabrics treated with CTAB against E. coli at pH=7. 0.5 1 2 CTAB % Reduction of 90 99.9999 99.9999 bacteria on polypropylene Reduction of 90 99.9999 99.9999 bacteria on Dolvester Table 2. Antimicrobial activity of polyester and polypropylene fabrics treated with CTAB against S. aureus at pH=5.5. CTAB Yo 0.5 1 2 Reduction of 90 99.9999 99.9999 bacteria on polypropylene Reduction of 90 99.9999 99.9999 bacteria on polyester


Table 3. Antimicrobial activity of polyester and polypropylene fabrics treated with CTAB against P. aeroginosa at pH=5.5. CTAB % 0.5 1 2 Reduction of 90 99 99.99 bacteria on polypropylene Reduction of 90 99 99.99 bacteria on polyester Table 4. Antimicrobial activity of polyester and polypropylene fabrics treated with mixture of CTAB and FC1112 against E. coli at pH=7. CTAB % 0.5 1 2 Reduction of 90 99 99.9999 bacteria on polypropylene Reduction of 90 99 99.9999 bacteria on polyester Table 5. Antimicrobial activity of polyester and polypropylene fabrics treated with mixture of CTAB and FC1112 against S. aureus and P. aeroginosa at pH=5.5. CTAB Yo 0.5 1 2 Reduction of 90 90 99.9999 bacteria on polypropylene Reduction of 90 90 99.9999 bacteria on polyester The results for water and blood drop absorption are presented in Table 7. The results showed that application of fluorocarbon on both polyester and polypropylene fabrics could produce a fabric with acceptable water and blood repellent properties as the time of water and blood absorption increases rapidly. The surface tension of water is 72 dydcm and natural blood is around 52 dyn/cm. This means that these materials can spread rapidly on the polyester and polypropylene fabric surface. Application of fluorochemical reduces the surface energy of the fabric and do not permit the water or blood droplet to adsorb and spread on the fabric surface. With application of sufficient amount of fluorochemical on the fabric surfaces, It is possible to produce a fabric with water and blood repellent properties. This research showed that the amount of 2% fluorochemical was sufficient to produce a fabric with reasonable water repellent Property. 0 Woodhead Publishing Limited, 201 0 167

The results of co-application of fluorochemical with CTAB indicated that these two chemicals have a good compatibility and could produce a fabric with multifunctional properties, as the fabric is antimicrobial as well as water and blood repellent. Table 6. Antimicrobial activity of polyester, polypropylene and white and dyed viscose fabrics treated with CTAB measured by AATCC 90 (zone of inhibition) Fabric Percent of materials bacteria CTiU3

FC

Polypropylene

0

0

Polyester

0

0

White Viscose

0

0

Dyed Viscose

0

0

Polypropylene

3

0

Polyester

3

0

White Viscose

3

0

Dyed Viscose

3

0

Polypropylene

2

0

Polyester

2

0

White viscose

2

0

Dyed Viscose

2

0

Polypropylene

1

0

Polyester

1

0

White Viscose

1

0

+

Dyed Viscose

1

0

+

Polypropylene

0.5

0

Polyester

0.5

0

White Viscose

0.5

0

Dyed Viscose

0.5

0

Polypropylene

2

2

+

Polyester

2

2

White Viscose

2

2

+ +

Dyed Viscose

2

2

+

P.aeroginosa

E.coli

Saureus

+ + + + + +

+

+ + + + + +

+ +

4-

+ + + + + + +

+

+ + + +

+ +

+ + + +


Table 7. Droplet absorption time for the samples treated with Fluomchemical andor TAB Time of absorption (seconds) % FC Water Blood Fabric 0 Less than 5 Less than 5 Polypropylene Less than 5 0 Less than 5 Polyester Less than 5 0 Less than 5 White Viscose Less than 5 0 Lessthan5 Dyed Viscose More than 1800 1 More than 1800 Polypropylene More than 1800 1 More than 1800 Polyester 1 More than 1800 More than 1800 White Viscose More than 1800 1 More than 1800 Dyed Viscose More than 3600 2 More than 1800 Polypropylene More than 3600 2 More than 1800 Polyester More than 3600 2 More than 1800 white Viscose More than 3600 2 More than 1800 Dyed Viscose More than 3600 3 More than 3600 Polypropylene More than 3600 3 More than 3600 Polyester More than 3600 3 More than 3600 White Viscose More than 3600 3 More than 3600 Dyed Viscose More than 1200 2%FC+2%CTAB More than 1200 Polypropylene More than 1200 2%FC+2%CTAE3 More than 1200 Polyester More than 1200 White Viscose 2%FC+2%CTAB More than 1200 2%FC+2%oCTAB More than 1200 More than 1200 Dyed Viscose CONCLUSIONS Synthetic fibers such as polypropylene and polyester are commonly used in the construction of surgical drapes and gowns as well as viscose. Antimicrobial nonwoven fabrics were prepared by directly incorporation of a qurtemary ammonim salt namely, cethyl trimethyl ammonium bromide, on polyester and polypropylene and viscose nonwoven fabrics. An interesting observation is the clear zone of inhibition and excellent reduction of bacteria growth on polyester and polypropylene fabrics. It is apparent that the antimicrobial activity of CTAB is bactericidal in nature and not bacteriostatic. CTAB was effective as antibacterial agent on E.coli for three different fabrics. However CTAB was not effective on S. aureus and P. seudomonas when applied to viscose fabrics which may suggest that nature of substrate influence on the antibacterial activity of CTAB. The antimicrobial and fluorochemical finishes used in this study were miscible in a single bath and could be applied to nonwoven fabrics to impart the desirable properties. REFERENCES 1 H S Seong, J P Kim and S W KO,‘Synthesis of quaternary ammonium derivative of chito-oligosaccharideas antimicrobial agent for cellulosic fibers’, Textile Res J 1999 69 483-488. 2 B C Gosawami J Suryadevara, T L Vigo, ‘Determination of Poisson’s ratio in thermally bonded nonwoven fabrics’, Textile Res J,51 1981 54(6) 391-396. 0 Woodhead Publishing Limited, 201 0 169

3 T Nakashima, Y Sakagami, H Ito, M Matsuo, ‘Antimicrobial activity of cellulose fabrics modified with metallic salts’, Textile Res 4 2001 71 688-694. 4 M Diz, M R Infante,P Ena, A Manresa, ‘Antimicrobialactivity of wool treated with a new thiol cationic surfactant’, Tatile Res J, 2001 71 695-700.

5 S Tan, G Li, J Shen, Y Liy M Zong ‘Study of modified polypropylene nonwoven cloths’, Journal ofApp1 Polymer Sci, 2000 77,1869-1 876.

6 S Lee, J S Cho, and G Cho, ‘Antimicrobial blood repellent finishes for cotton and nonwoven fabrics based on chitosan and fluropolymm’, Textile Res J, 2000 69 104-112. 7 G Sun et al, ‘Antimicrobial medical - use textiles’, The 6* Asian c o d Hong Kong, 22-24, Aug 2001. 8 P Zhu and G Sun, ‘Antimicrobial finishing on wool fabric using quaternary ammonium salts’, Journal ofApp1 Polymer Sci, 2004 93(3) 1038-1041.

9 Y Shin, K Son, D I Yoo, S Hudson, M McCord, S. Matthews and Y. J. whang, ‘Functional finishing of nonwoven fabric accessibility of surface modified PET spunbond by atmospheric pressure plasma treatment’, Journal of Appl Polymer Sci, 2006 100 4306-4310. 10 Y A Son and G Sun, ‘Durability of anthicrobial on nylon66 fabric: Ionic interaction with quaternary ammonium salts’, Journal ufAppl Polymer Sci, 2003 90 2194-2199. 11 J A Moylan, K T Fitzpatrick and K E Davenport, ‘Reducing would infections. Improved gown and drape barrier performance’, Arch Surg, 1987 122 152-157.


DEVELOPMENT OF SURGICAL CLOTHING FROM BAMBOO FIBRES K. Ramachandralu PSG College of Technology, Coimbatore, India ABSTRACT Sanitation and hygiene are the most important aspects of health. They display greater significance in medical field particularly during the course of surgery and post surgery. The patients undergoing surgery and also the surgeons and paramedical staff assisting surgery need secure protection against infections. The urgent need is to provide them with suitable surgical wears that can natwally resist the growth of infectious microbes. The advent of bamboo fibre which is bestowed with the inherent property of inhibiting growth of bacteria by its natural ability of sterilization and bacteriostasis qualify its usage in apparel and home textiles and hygiene products An attempt has been made in this research work to extend its usage to medical textiles, particularly to develop surgical robe, face mask and caps- from bamboo fibre. 30s Ne yams were produced out of bamboo fibre and cdton in five different types namely, 100% bamboo fibre, and bamboo I cotton blends of 80:20, 70:30,60:40 and 5050 and knitted into single jersey fabrics. All these fabric samples were evaluated for their anti bacterial characteristicsqualitatively by parallel streak method. The results reveal that fabric made of 100% bamboo fibre is able to inhibit bacterial growth effectively, where as in case of blended fabrics it is observed that as the percentage of cotton increases, the antimicrobial effectiveness decreases. Subsequently, surgical wears such as surgeon's gown, face mask and caps were constructed out of 100% bamboo fabric. The anti bacterial assessment of the surgical wears made fioml00% bamboo fibres was carried out and compared with commonly used surgical wears made from 100% cotton after using them in actual hospital condition during a surgery. Their effectiveness towards inhibiting bacterial growth were evaluated by Blood agar plate method qualitatively and quantitatively as well as by turbidity method. The results revealed that the use of 100% bamboo fibre in surgical wears inhibits the growth of bacteria. It has been proven in this research work that surgical wears could be manufactured from bamboo fibres and effectively used for better sanitation and hygiene in hospitals. INTRODUCI'ION

Thanks to the extensive research by fibre scientists, the dawn of the 21" century has witnessed the introduction of many new fibm possessing improved functional characteristics. Bamboo is one such new generation fibre with cellulose base, regenerated h m bamboo stems. It possesses certain improved characteristics l g such as better moisture absorption, quick drying, excellent anti microbial, anti odour, ultra violet proof, cool sensation on skin, soft feel etc. Bamboo fibre derives its antibacterial strength h m a unique anti bacterial and bacteriostatic bieagent called bamboo kun. The manufactureIs of this fibre'*23claim that it can be used for producing intimate apparels such as unckrwears , banians, socks etc., home textiles such as bath robes, mats, towels etc., hygiene and sanitary products such as sanitary napkins, bandages, gauzes etc., and summer clothing for pregnant


women and children. Unfortunately there is a dearth of information / data on the real effectiveness of this fibre on various applications. No literature other than the manufacturer’s claim are available. Hence an attempt has been made in this research work to spin this fibre and its blends with cotton into yarns and convelt these yarns into single jersey fabrics and to evaluate their various characteristics and particularly their anti bacterial characteristic. In this research work, exploiting the antimicrobial characteristic of bamboo fibre, surgical wears such as surgeons gown, mask and caps were developed out of the single jersy fabrics made of 100% bamboo fibres and their effectiveness towards inhibiting bacterial growth in actual hospital conditions were evaluated. This paper is based on the above developmental work and evaluation of the yarns and fabrics made of bamboo fibres and bamboo cotton blends and their subsequent characterizations, particularly their anti bacterial characteristics.

MATERIALSAND METHODS 30s Ne yarns were produced out of 1.5 D Bamboo fibres of 38mm cut length and cotton in five different proportions namely 100% bamboo fibre and bamboo / cotton blends of 80:20, 70:30,60:40 and 5050 in actual mill conditions with the same process parametersand tested for their physical characteristics such as tenacity, elongation, evenness and imperfections They were knitted into single jersy fabrics and dyed using reactive dye. These fabrics samples were evaluated for their mechanical characteristics such as abrasion resistance, pilling resistance and bursting strength, wettability and washing fastness using standard testing instruments following standard testing methods 436. Then the samples were tested for their anti bacterial characteristics qualitatively by Parallel Streak Method using the organism Staphylococcus a m u s following AATCC 14711998 procedure5. Based on the results in terms of their effectiveness to inhibit the growth of bacteria, the bamboo / cotton blend proportions were optimized. As the fabric made of 100% bamboo fibre was found to be effective in inhibiting bacterial growth, it was considered for the development of surgical wears. From the fabric made h m 100% bamboo fibres, surgeons gown, caps and masks were constructed. These wears were used during a surgery in a hospital along with the surgical wears made from 100% cotton, which are regularly used by the hospital. After usage these wears were evaluated for their effectivenesstowards inhibiting bacterial growth 1” X 1” qualitatively and quantitatively by Blood agar plate method. Tnthis method fabric samples were cut from the surgical wears made fkom 100% bamboo fibre (newly developed) and the surgical wears made fiom 100% cotton (regularly used by hospital) which were already exposed to surgical conditions. These samples were placed in plates with k s h l y prepared blood agar medium, and incubated at 37°C for 24 hrs. The qualitative assessment of bacterial growth was done based on the bacterial colonies developed after 24 hrs. ’Ihe quantitative assessment was carried aut simultaneously by taking the 1” X 1” fabric samples cut from the surgical wears made from 100% bamboo fibre and 100% cotton which were exposed to the surgical conditions in the hospital and immersing them separately in 10 ml of sterile distilled water and kept in the shaker for 10 min. Then 0.1 mi of water taken h m each suspension, was spread plated on the blood agar medium separately and the number bacterial colonies grown after 24 hrs. incubation at 37°C was estimated by counting the number of colony forming units. The bacterial assessment was also done qualitatively by Turbidity method in which the 1” X 1” fabric


samples cut from the surgical wears made from 100% bamboo fibre and 100% cotton d i c h were exposed to surgical conditions in the hospital were taken and immersed separately in test tubes containing 10 ml nutrient broth which was inoculated with Staphylococcus aureus and incubated for 24 hrs at 37°C. The test tubes were observed for bacterial growth based on the turbidity created in the brcrh. The results were analysed and conclusions were drawn.

RESULTS AND DISCUSSIONS Physical characteristicsof the yarns The comparison of the physical characteristics of the yarns made of 100% bamboo fibre and bamboo fibre I cotton blends are given in Table 1. Table 1

Characteristic Tenacity (RKm) Breaking Elongation (YO) Um % Thin placed km Thick placed km N e d km

Physical characteristicsof the yams Blend Proportion Bamboo: Bamboo: Cotton Cotton 70:30 (%) 60:40 (%) 12.06 12.62

Bamboo: Cotton 5050 (%) 10.68

13.34

BalThO: Cotton 80:20 (Yo) 12.33

14.87

9.65

8.09

8.08

5.18

13.74 78

10.95 3

10.95 4

10.92 5

11.93 34

22 1

26

21

18

75

442

58

61

48

87

Bamboo 100 Yo

Table 1 shows that the yarn made fiom 100% bamboo fibre possesses higher tenacity and much higher elongation % when compared to the yams made from bamboo I cotton blends. But it is found to be highly uneven and having very high level of imperfections when compared to blended yarns.


Mechanical Characteristics of fabriar made of 100% bamboo fibres and bamboo fibdcotton blends The comparison of the mechanical characteristicsof the single jersy fabrics made of 100% bamboo fibre and bamboo fibre / cotton blends are given in Table 2. Table 2 Mechanical Characteristics ofFabrics Characteristics

Abrasion resistance ( %weight loss) Pilling Resistance grade Bursting Strength (lbdinche.?) Wash fastness Change in shade -grade Staining on Cotton - grade Water Repellency Spray Rating

Test Method

D 4966 / 1998

Bamboo 100%

2.34

AATCC 22,2005

Bamboo: Cotton 60:40

Bamboo: Cotton

(%)

(%)

(%)

(YO)

2.87

5050

4.04

4.40

3

3

4

77.7

75.6

74.2

56

4

4

4

4

4

4

4

4

4

4

0

0

0

0

3

81.1

1975

AATCC 6lA, 2003


3.85

IS 10971/ 1984

IS19661


Abrasion resistance

From Table 2 it is evident that the fabric made fkom 100% bamboo fibres is more resistant to abrasion when compared to the ones made h m bamboo fibdcotton blends and the abrasion resistance decreaseswith the increase in cotton content. Pilling resistance

It could be seen in Table 2, that the hbric made fiom 100% bamboo fibres are more prone to pilling when compared to the fabrics made from bamboo fibrehotton blends and as the percentage of cotton in the blend increases the pilling resistance also increases.


Bursting strength

From Table 2 it could be understood that the fabric made h m 100% bamboo fibres has higher bursting strength when compared to bamboo fibrehotton blended fabrics and t k increase in cotton percentage in the blendsreduces the bursting strength of the fabric. Wettability

The values of spray rating as given in Table 2, for the fabrics made from 100% bamboo fibre as well as the bamboo fibre'cotton blends show that they possess good absorption characteristic,which is evident fiom their wetting behaviour. Washingfastness

It could be seen from Table 2 that the fabrics made from 100% bamboo fibres and also bamboo fibrelcotton blends possess good colour fastness to washing and staining on cotton.

Anti bacterial characteristics The anti bacterial characteristics of the fabrics made from 100% bamboo fibre and bamboo fibrekotton blends as evaluated by parallel streak method and the qualitative and quantitative assessment of bacterial growth in the 100% bamboo fibre material (newly developed) and the in cotton material (regularly used by the hospital) which were exposed to surgical conditions by blood agar plate method and the assessment by Turbidity method are given as below. Evaluation by parallel streak method

Anti bacterial behaviour of the fabric samples made from 100% bamboo fibres and bamboo fibre I cotton blends inoculated with Staphylococcusaureus after 24 hrs. incubation at 37°C following parallel streak method is shown in the form of photographs in Figs. 1,2,3,4, & 5.

Fig. 1 Bacterial growth in the fabric made h m 100% bamboo fibre


Fig. 2

Bacterial growth in fabric made from 80:20 bamboo fibre : cotton blend

Fig. 3 Bacterial growth in fabric made h m 70:30 bamboo fibre :cotton blend

Fig. 4 Bacterial growth in fabric made from 60:40 bamboo fibre : cotton blend


Fig. 5 Bacterial growth in hbric made &om 50:50 bamboo fibre :cotton blend From Figures 1,2,3,4 & 5 it could be seen that the 100% bamboo fibre fabric is able to inhibit the bacterial growth to a greater extent when compared to the bamboo fibrehotton blended fabrics and it could be seen h m Fig.5 that the 5050 bamboo fibre : cotton blend inhibiting bacterial growth to the lowest extent Qualitative and quantitative assessment by blood agar plate method

The bacterial growth in the blood agar plates for 100% bamboo fibre material (newly developed) as well as 100% cotton material (regularly used by the hospital) is depicted in the form of photographs in Figs. 6 & 7.

Fig. 6 Bacterial growth in surgical wears made from 100% bamboo fibre and 100% cotton From Fig.6 it could be seen that the blood plate with bamboo fibre material exhibits less bacterial colonies when compared to the blood agar plate with cotton material. It is to be noted that both the materials wcre exposed to the same surgical conditions.


Fibre

Fibre

Fig 7 Bacterial colony forming units in surgical wears made h m 1OOOh bamboo fibre and 100% cotton From Fig. 7 the number of bacterial colonies developed after 24 hrs incubation in blood agar medium could be easily counted as they are visible clearly. On counting, it was found out that bamboo fibre material contained 32 X Id colony forming units of bacteria, whereas in case of cotton material it was 127 X Id colony forming units of bacteria. From the results of the blood agar plate method, it is very clear that the material made of bamboo fibres is able to inhibit the growth of pathogenic bacteria effectively. Evaluation by turbidity method

The photograph showing the test tubes containingnutrient broth in which the samples of 100% bamboo fibre material and 100% cotton material (which were exposed to actual surgical conditions) were immersed and inoculated with Staphylococcus aureus and incubated for 24 hrs at 37" C, is shown in Fig.8.


1OO??Cotton Fibre

Fibre

Fig. 8 Nutrient broths with 100% bamboo fibre material and 100% cotton material It could be seen from Fig.8 that in the test tube with cotton material sample, the nutrient broth is turbid. But in the test tube with bamboo material immersionthe nutrient broth is clear. The development of turbidity in the nutrient broth is a clear indication of bacterial growth. Staying clear after 24 hrs incubation, the bamboo material has proved its anti bacterial characteristic.

CONCLUSIONS Following conclusions are drawn from this research work. 0 The yarn made from 100% bamboo fibre is very uneven with higher imperfection level when comparedto the yarns made of bamboo fibre I cotton blends. 0 The single jersey fabric made fbm 100% bamboo fibre possesses higher abrasion resistance, lower pilling resistance, higher bursting strength when compared to the single jersey fabrics made h m bamboo fibre I cotton blends. The increase in cotton content reduces the bursting strength and the abrasion resistance and increases the pilling resistance . 0 The single jersey fabric made from lOO?h bamboo fibre possess good wettability and washing fastness characteristics which are at par with the fabrics made of bamboo fabric 1cotton blends. 0 The knitted fabric made from 100% bamboo fibre exhibits good anti bacterial characteristics. It is found to be effective in inhibiting bacterial growth, when compared to


the fabrics made h m bamboo fibre I cotton blends. In fact the presence of cotton in the blend reduces the effectivenessto inhibit bacteria. 0 This research work has confumed the antibacterial characteristic of bamboo fibre and thrown light on its effective application in surgical wears. Aclmowledgementa

The author is tbadchl to the undergraduate Apparel & Fashion Technology students of PSG College of Technology M/s. Fatima K. Moaiyadi, Joy Olivia Isaiah, Kerry Renaux, Nivas.K.M. and Pavithra.J. for carrying out the experiments. The author thanks the management of M/s. Kannapiran Mills Ltd., Coimbatore and their R&D officer h4r.P.Madava Murthi for producing the yam samples from bamboo fibre and cotton blends and providing the same for the research work The author is thankful to the Management of PSG Hospitals, Coimbatom for their valuable help in testing the samples in actual surgical conditions. The author thanks Dr.MAnantha Subramanian, AsstProfessor, Dept. of B b Technology, PSG College of Technology for the useful discussions on micro biological aspects of the research work

REFERENCES 1 www.bambrotex.com 2 www.tenbro.com

3 www.bamboofabricstore.com 4 ASTM International book of Standards, 2004

5 AATCC Technical Manual, 2001 6 Indian Standards Book, 1975


THERMAL CHARACTERIZATION AND MECHANICAL PROPERTIES OF PLA YARNS A M Manich', D Cayuela2,M Marti', R M Sam'' and M Ussman' 'CSIC - Spanish Council for Scientific Research, Barcelona, Spain 21NTEXTER, UPC - Technical University of Catalonia, Terrassa, Spain 'UBI - Universidade da Beira Interior, CovilhB, Portugal

ABSTRACT Commercially available PLA plain weave fabric of 245.26 g/ma, 0.85 mm in thickness formed by 29.5 warp yarnshm of 41.6 tex and 14 weft yarndcm of 92 tex. After being washed with non-ionic surfactant and rinsed, dry and wet samples were subjected to thermal treatment a t 1215OC during 3 hours to induce some kind of recrystallisation in order to modify their mechanical properties. Another sample was subjected to plasma treatment in a radiohquency unit (13.56 MHz) in vacuum conditions (0.05 mbar) before introduction of air as plasma generator. Treatment was performed a t 1 mbar for 6 minutes a t 100 W. All samples were immersed in phosphate buffer solution (pH=7.4) for a week at 40°C in order to obtain different PLA treated samples. Thermal charaeterization was done by DSC and Thermo Mechanical Analyzer which gave values of thermal transition and relative crystallinity of the samples. The TMA gave information about glass transition and Dilatometric transitions due to temperature. Mechanical properties were measured by testing mechanical properties in single strand, knotted and laced form, and also elasticity and relaxation behaviour of yarns were characterized by measuring the immediate elastic recovery, the delayed recovery and the permanent deformation of yarns. Stress relaxation was modelled by the application of three Maxwell units in parallel to evaluate the high-rate, the medium rate and the low rate relaxed stress of yarns. Lastly mechanical properties of fabrics were measured by the bursting strength and the bagginess of fabric after being subjected to cyclic multiaxial strain test. Performed tests gave important information to bandaging and pressure medical devices.

INTRODUCTION (Polylactic acid) PLA is linear aliphatic thermoplastic polyester derived from 100% annually renewable crops. Most initial uses were limited to biomedical applications such as sutures and drug delivery systems due to availability and cost of manufacture. PLA fabrics can be used to cultivate different human organs. The process involves culturing and growing living cells, taken from human organs, on a textile scaffold, to the desired 2-dimensional andor 3 - d h e n s i o d shapes. PLA can be used in this application because it is a biodegradable and resorbable fibre. During the process of degradation, fibrous connective tissues replace the degrading implant. The kcy advantage is that no further surgery is required to remove the products since they slowly degrade in the body without any side effects [l]. When designing PLA tissue engineering scaffolds, the length of time it takes for the polymer to degrade, must be investigated [2]. The objective of this work is to apply different characterization techniques in order to test their sensitiveness in relation with the degradation level of the PLA. Thermal, thermomecanical and mechanical testing procedures have been applied to monitor the variation induced on a commercially 0 Woodhead Publishing Limited, 201 0 181

available PLA fabric which has been subjected to dry heat high tempera& method and degradation in phosphate buffer solution pH 7.4.

sterilisation

MATERLAL

PLA plain weave fabric sample of 245.25 g/mz, 0.85 nun in thickness formed by 29.5 warp y d c m of 41.5 tex and 14 weft yamslcm of 92 tex were used. The sample were washed using non-ionic surfactant, rinsed and then dried in standard atmosphere. Treatmenta Sferilisation was made using the dry heat high temperature method. Dry and wet samples were subjected at 125OC during 3 hours to attain their complete sterilisation. The sterilisation process can induce some kind of annealing, melting and recrystallisation modifjmg their fine structure. Surface modification. A washed sample was subjected to plasma treatment in a radiofrequency unit (13.56 MHz) in vacuum conditions (0.05 mbar) before introduction of air as plasma generator. Treatment was performed at 1 mbar for 5 minutes at 100 W. Initial Degradation. All samples were immersed in phosphate buffer solution (pH=7.4) for a week at 37°C in order to obtain an initial estimation of the degradability of the washed, sterilised and plasma-treated samples. Strong Degradation. After the estimation of the initial degradation, the samples were subjected to an accelerated degradation process by immersion in phosphate buffer solution (pH=7.4) at 5OoCduring four weeks. The identification of the samples according to the treatments were subjected to the following: 0

Reference

Washing

Sterilisation

Surface Initial Strong modification degradation degradation

dry sample wet sample

X

0-OR 1-wD 2-STd 3-STw

X

4-SL 5-PT

X

11-WDSd 2 1-STdsd 3 1-STWSd 41-SLsd 51-PTd

X X

X

X X

X

X X

X

X

dry sample

X

X

X

wet sample

X

X

X

X

X

X

X X -

X

METHODS

Thermal and Thennomechanical method8 DSC: Trials have been performed in a Mettler-Toledo DSC 823 unit using 40 p1 sealed pans containing approximately 6 mg of PLA with the following conditions: Initial 182 0 Woodhead Publishing Limited, 2010

temperature 30°C, final temperature 2OO0C, heating rate 10°C/min, and purging gas nitrogen 50mI/min. T M : For Thermomechanical analysis a Mettler-Toledo T W S D T A 840 was used. The substrates were prepared in a special support for filmdfabrics cutting rectangular samples in warp and weft direction of 1575x6 mm being tested with gauge length of 10 mm. Tests were performed under the following conditions: Initial temperature 25"C, final temperature165"C, heating rate 2"C/min, dynamic loading between 0.1 and 0.2 N at 1/12 Hz,purging gas nitrogen 35 ml/min.

Mechanical propertics Yarn Tensile properties: Specimens with gauge length of 100 mm were tested after being conditioned in a standard atmosphere for 48 hours. Breaking load [N] and strain [%I in single strand knotted and laced form were determined on yams subjected to tensile testing at 60%/min accordingto the ASTM D 2 101 Standard [3].

Yarn Stress Relaxation test: Five specimens with gauge length of 100 mm were tested after being conditioned in a standard atmosphere for 48 hours. Specimens were subjected to 25% at 60%/min in the MT-LQ dynamometer. The average of the initial stress q and stresses at 1,2,3,4, 5,6,7, 8, 10, 12, 14, 16, 18,20,25,30,35,40,45,50, 60,70,80,100,120, 140,160 and 180 seconds were recorded. Fitting the Stress Relaxation Model: The relaxation times were pre-selected TO = 1 s, z1= 10 s and z2 = 100 s to differ between them in one order of magnitude and to be placed into the length of time of the stress-relaxationtest according to Vitkauskas's conditions [4].Based on the pre-selected relaxation times, the multiple regression analysis [5, 61 was used to obtain the estimators of high-rate 00, medium-rate ( ~ 1 , low-rate 0 2 relaxed stresses and ofthe non-relaxed or final stress. The determination coefficients of the all fitted multiple regression equations were approximately of 99.96%. All the terms were highly si&icant, which explains that relaxation is produced as a consequence of three relaxation processes occurring in parallel (cfi. Figure 1). Values of reduced stress obtained by dividing the stress observed at time t by the initial stress oi expressed in % were used.

Figure 1: a) Maxwell unit, b) Generalized Maxwell model to account for the stress relaxation of PLA yarns 0 Woodhead Publishing Limited, 201 0 183

Yarn Elasticity: The elastic properties of the yams using an Instron 5500R dynamometer and applying the ASTM standard with small modifications [7]. Two deformation cycle testing were performed defined by the maximum load Qmax of 5 N at 30N/min which the specimens 100 mm in length are subjected according to the procedure schematically presented in Figure 2. The waiting time between the first and the second cycle was 3 minutes. The trigger load at which the immediate elastic recovery, the delayed recovery and the permanent set were measured was 5% of the maximum load Qmax. Fabric Bursting strength: A h4T-LQ Stable Micro Systems dynamometer equipped with a clamping device for securing the fabric sample and a probe for producing fabric bursting has been used. A circular area of fabric is clamped around its circumference. A circular area of 25 mm i 0.1 mm diameter must be exposed for testing. The clamping device should be positioned centrally above the probe. A cylindrical probe comprised of steel with a hemispherical test head of diameter 9 mm 0.1 mm (the hemispherical head should have a radius of curvature of 20 mm) and a length suitable to allow ease of testing up to fabric breakage. The zero position for this test shall be taken as the point where the probe contacts the fabric resulting in a force of 0.25 N. The probe shall move from zero position towards the fabric surface at a speed of 1 mm/s until fabric breakage is produced. The maximum of the stress-strain curve allows determining the breaking strength and the breaking deformation of the fabric. Normally four samples are tested and the mean breaking strength and deformation are given.

f

Figure 2: Two cycle test at a maximum fixed load for the determination of the elasticity and plasticity of PLA yarns: Straining at the maximum load S1, Immediate Elastic Recovery ER, Delayed Recovery DR and Permanent Set PS. The trigger load was 5% of Qmax.

Relaxation, Creep and Fabric Bagginess: A probe is pressed against a sample disk, which is firmly held around its circumference, until a load equal to 75 N is applied. The deformation achieved at this force is held for 10 seconds and then the load is removed. This process is repeated for 5 cycles. Afterwards, the sample is allowed to relax for 60 184 0 Woodhead Publishing Limited, 2010

seconds and the residual deformation in mm (bagginess index) is measured. The following graphs of force versus time and displacement versus time are obtained (See Figure 3 a and b) [8,9]. The method was origmally made up to measure the bagginess index; this is the residual deformation of a sample after cyclic multi-axial strain. Moreover, it has been proved to be also useful to study creep, or time dependent change in strain following a change in stress, and stress-relaxationor decreasing of stress along time when applying a certain strain. As it can be observed in Figure 3 a, it is possible to quantify the phenomenon of stress-relaxation within each cycle. The value of force is determined 1, 2,4, 6 and 8 seconds after the application of an initial load of 75 N in each cycle. The graphical representation of these values versus the ln(time(s)) leads to the adjustment of a linear equation whose slope is the stress-relaxation index. On the other hand, the phenomenon of creep can be quantified by determining the value of displacement in each cycle. The graphical representation of these five values versus ln(cyc1e nr.) allows the adjustment of a linear equation whose slope is the creep index [9] (Fig 3 b). This method also provides a simple and quick way to measure the fabric bagginess index.

RESULTS DSC: Generally speaking, sterilisation of dry and wet samples increases the glass transition temperature of the PLA fibre from 66°C to 74°C approximately, and degradation additionally increases the glass transition in 2OC.

Figure 3: a) Graph Force vs Time and b) Graph Displacement vs Time obtained in the bagginess/creep/stress-relaxation 0 Woodhead Publishing Limited, 2010 185

The melting endotherm shows two peaks with temperature peaks at about 162.3"C and 1695°C. Washing,sterilisation and degrading do not affect peak temperatures, although degradation decreases the second peak temperature in 1°C approximately the wet sterilised sample decreases by more than 2.5"C. Strong degradation induces relevant differences in the relative height of the two peaks. It increases the height of the 1' peak at expenses of the second one being the highest ones those of the sterilised samples. The Plasma treated sample showed scarce differences between the melting peak heights.

TUA: Temperature change can lead a material through Merent transitional phases. These can cause the specimen to expand, contract, to melt and recrystallise or to go through a major structural changes [lo, 113. Before meting PLA fibre begins to sbrink. The onset temperature of retraction was near 160°C for the non degraded samples and 154°C for the strongly degraded ones. The lowest onset temperature of retraction was that of the strong degraded plasma treated samples. The melting temperature measured at the TMA showed very highly significant dif€erences between non degraded and degraded PLA samples. Tm of the original samples was near 161°C approximately, while Tm of the degraded ones was approximately of 153°C. This confirms that degradation affect the more perfect crystals with higher melting temperatures favouring the formation of crystals of lower size and perfection. Yarn tensile properties: No big differences were observed between single strand, knotted and laced f o m The mean values in breaking strength and deformation in single strand of warp and weft samples will be reported in Table 1. Table 1. Breaking strength and strain of single PLA yams Reference Breakstrength Break.strain Reference Breakstrength Breakstrain 0-OR 6.75 N 35.47% 1-wD 6.50 N 34.00% 11-WDsd 2-STd 6.56 N 35.26% 21-STdsd 4.03 N 14.94% 3-STw 6.07 N 33.15% 31-STwsd 3.88 N 14.44% 4-SL 6.35 N 33.25% 41-SLsd 3.30 N 8.74% 5-PT 6.01 N 29.17% 5 1 -PTsd 3.58 N 10.61% Yarn mess relaxaiion test: After strong degradation no relaxation tests straining at 25% were possible to be performed because strong degradation decreases breaking strain under 25%. The mean values in the initial load at 25% straining, and the high-rate, medium-rate, low-rate and final non-relaxed load in % of the initial load of warp and weft Samples will be reported in Table 2. Table 2. Yam relaxation test. High-, medium-, low-rate relaxed and non-relaxed load Reference

Initial Load

High-rate

25% straining relaxed load

0-OR 1 -wD 2-STd 3-STw 4-SL 5-PT

4.22 N 4.24 N 4.23 N 4.30 N 4.11 N 4.21 N

14.12% 14.14% 13.47% 13.38% 13.39% 14.46%

Medium-rate relaxed load 11.06% 10.86% 10.73% 10.37% 10.94% 11.36%

Low-rate Final nonrelaxed load relaxed load 12.79% 61.92% 12.57% 62.36% 11.97% 63.73% 12.29% 63.86% 12.48% 62.60% 12.45% 61.71%


Yarn elasticity: After strong degradation no elasticity tests were possible to be performed because the strong degradation decreases breaking load under 5 N. The mean values of the initial deformation at 5 N and the immediate elasticity, the delayed elasticity and the permanent set in % of warp and weft samples are reported in Table 3. Fabric Bursting strength, relaxation, creep and bagginess: Results of bursting strength and deformation, and results of relaxation index, creep index and bagginess after 5 cycles of deformation at 75 N made on the original and the washed samples and on the strongly degraded samples are given in Table 4. DISCUSSIONAND CONCLUSIONS The diffmntial scanning calorimetry allows us to identify variations in glass transition and melting of PLA. It has been proved that sterilisation increases glass transition temperature fiom 66 to 74°C and degradation additionally increases Tg in 2°C. Although the two peak melting endotherm temperatures were 162.3 and 169.5OC treatments influence the height of peak. The strong degradation increases the heigh of the low temperature peak at expenses of the high temperature peak, especially in the case of sterilised samples. It means that sterilisation degrades the high size and more perfect crystals contributing to the formation of low size less perfect crystals with lower melting temperature. Table 3. Elastic characteristics and permanent set of yarns strained at 5 N Reference 0-OR 1-wD 2-STd 3-STw 4-SL 5-PT

Initial strain at 5N 19.11 % 18.47 % 20.11 Yo 19.44 % 19.60 % 18.59 %

Immediate Elasticity 20.91 % 21.67 % 22.82 Yo 22.23 % 21.35 Yo 21.80 %

Delayed Elasticity 21.26 % 21.49 % 23.88 Yo 23.28 Yo 22.28 Yo 23.31 Yo

Permanent set 57.83 % 56.84 % 53.30 Yo 54.49 Yo 56.38 % 54.89 %

Table 4. Fabric bursting strength and strain and relaxation, creep and bagginess after five deformation cycles at 75 N Reference 0-OR 1 -wD 2 1 -STdsd 31-STw~d 41-SLSd 5 1-PTd

Bursting strength 358.0 N 348.0 N 301.3 N 265.0 N 240.9 N 237.2 N

Bursting deformation 8.89 mm 8.53 mm 8.22 mm 7.62 mm 7.43 mm 7.33 mm

Relaxation index 2.289 2.223 2.057 2.522 2.286 2.486

Creep index 0.219 0.216 0.207 0.212 0.219 0.269

Bagginess index 2.109mm 2.686mm 2.516mm 2.551 mm 2.807 mm 3.310rnm

The Thennomechanical analysis reveals the same influence. The onset temperature of retraction for non degraded samples that is observed at 160"C, is decreased by degradation in 6°C which confirms that degradation affect the more perfect crystals with higher melting temperatures favouring the formation of crystals of lower size and 0 Woodhead Publishing Limited, 201 0 187

perfection. The same effect can be observed about the melting temperature determined at the TMA. Surface modified samples by plasma showed the lowest temperatures of shrinkage and melting. As regards to the yam tensile properties the breaking strength and strain of strongly degraded yams decreased significantly. Sterilisation favours the resistance of the PLA against degradation and the surface modified PLA fibre by plasma seems to be more sensitive to the initial degradation than to the strong degradation of the fibre. In relation with the stress relaxation and the elasticity of yarns it was not possible to compare the results with the strong degraded yarns because. highly degraded yams cannot withstand the experimental conditions of the non-degraded yams. Nevertheless the effects of the sterilisation on those characteristicsof the PLA yarns were observed: Sterilised yams showed lower relaxation and higher elasticity than that of the non sterilised ones. As regards with the fabric characteristics, bursting strength and deformation shows the effect of the strong degradation on these characteristics, and the high level of bagginess and creep of the strong degraded fabrics along five cycles of deformation were specially sigmficant. Summarising, themnomechanical analysis and mechanical testing of yams and fabrics were the more sensitive methods to monitor the degradation of the PLA fabrics when subjected to a degradation process into a phosphate buffer solution pH 7.4.

ACKNOWLEDGEMENTS Authors are indebted to the Spanish Project MAT2004-04981-C03-03 for its financial contribution. They recognise the contribution of the GRICESKSIC 2005PT005 1 Project helping the elaboration of the paper, and they are also indebted to Ms. R Mateu, A Lopez and C Martinez for its contributionto the experimental work.

REFERENCES 1 R S Blackbum, Biodegradable and sustainable Jibres, Woodhead Publishing Ltd. And CRC Press, Cambridge, pp 191-219,2005 S C Anand, J F Kennedy, M Miraftab and S Rajendran, Medical textiles and biomaterialsfor healthcare, Woodhead Publishing Ltd. And CRC Press, Cambridge, pp 58-66,2006

2

3 Standard Test Method ASTM D 2101 ‘Tensile properties of single man-made textile fibres taken from yarns and tows’, 1979

4 Vitkauskas, ‘Regular discrete relaxation time spectrum of textiles’, Medziagotyra (J Muter Sci), 1996 2 65-71 5 STATGRAPHICS Plus Statistical Software. Manugistics, Inc. 21 15 East Jefferson Street, Rockville, Maryland 20852, USA

6 N R Draper and H Smith, Applied Regression Analysis, 2”dEdition, J Wiley k Sons, New York, 1981 188 0 Woodhead Publishing Limited, 2010

7 Standard Test Method ASTM D 1774-79 ‘Elastic Properties of Textile Fibers’, 1979 8 A M Manich, T Bosch and A J Long, ‘Measurement of creep, relaxation and bagginess indexes of leather’, JSoc L a t h Tech Chem, 2000 84 133-136 9 A M Manich, M Marti, R M S a d , M D de Castellar and J Carvalho, ‘Effect of finishing on woven fabric structure and compressional and cyclic multiaxial strain properties”, Text Res J, 2006 76 86-93 10 J W S Hearle, Polymers and their Properties. Vol I :Fundamentals of Structure and Mechanics, Ellis Horwood Ltd. Publishers, Chichester, 1982 11 S K Mukhopadhyay,Advances in Fibre Science, The Textile Institute, 1992


189

PART 111 WOUND CARE MATERIALS

WOUND CAREMATERIALS AN OVERVIEW M. M i d b Institute for Materials Research and Innovation, The University of Bolton, Bolton, UK Wounds resulting from injury, disease or accidents need external intervention to help them repair and resume their normal bodily functions. Ideally, the repairs need to be neat and replicate the undamaged skin or organs as closely as possible. Hence any material or dressing that could potentially assist the repair process whilst providing suf€icient protection against possible bacteria spread in and out of the wound area is classified as “Woundcare Material”. Types and form of woundcare materials used are extensive and include a wide range of ~ t u r a and l synthetic materials. The available woundcare literature(*233) adequately covers the entire range of these products and their specific attributes, therefore this idormation will not be regurgitated in this short review. A concise reference to most woundcare materials has been made by the author in “Medical textiles and biomaterials for healthcare” Part fi4) and interested readers are referred to it. This review will instead concentrate on the latest research and developments where new and existing materials are increasingly amalgamated with intelligent and proactive natural andor manmade ingredients andor devices to achieve better and faster results. Over five million people each year in the UK suffer fiom various kinds of wounds that require treatment. As the age profile of the population increases, chronic or hard to heal wounds resulting from diabetes, pressure induced wounds, cancer and leg ulcers are becoming by far the most dominant and potentially most expensive types of wounds to treat. The cost to the NHS of caring for patients with a chronic wound is conservatively estimated at €2.3bn-3. lbn per year (at 2005-2006 .UK represents approximately 4% of the global costs hence the total worldwide expenditure on chronic wound treatments is in the region of E57.5-75 billion. It is therefore no surprise to see an explosion of new materials and products entering this market. Given this scenario and the resulting intense competition, it is no longer acceptable for a wound dressing to be; merely non-toxic, biocompatible, haemostatic and operate within the constraints of universally accepted “moist healing” theory. Dressings are today expected to be much more proactive and responsive to; the healing process, time constraints and scar free outcomes. WOUNDS NATURAL HEALING MECHANISMS VERSUS WOUND CARE MATERIALS

When an injury occurs, the body’s defence system is immediately mobilised starting with coagulation. This is brought about by migration of the platelets or the cells prcsent in the blood to the affected site and their subsequent exposure to fibrin, a protein responsible for causing haematosis. Growth factors are released from the platelets and the healing process is initiated from this very early stage. If the injury or the cut is deep and more serious, this leads to inflammation allowing migration of white blood cells to the affected area where they fight foreign matters whilst bringing along additional growth factors. Next, the wound undergoes proliferative phase where collagen deposition and granulation occurs followed by epithelisation where epithelial cells stretch across the wound bed and contraction begins. New blood vessels are finally formed and remodelling is initiated. This highly simplified trend of events leading to total recovery of the wound may not necessarily occur in the order described and 0 Woodhead Publishing Limited, 2010 193

overlap at various stages, but it’s a generalisaiion of the complex steps involved in the healing process. To be effective as a dressing, the wound dressing material needs to; stimulate, promote, and accelerate the above processes in some coordinated fashion so as to achieve medically better and aesthetically more acceptable results with minimal costs, where possible. Growth factors are fundamental to the healing process; from generating new epidermal skin to formation of granulation tissues and developing new blood vessels. Growth factors are classified according to their function and their availability at various stages of the healing process and it is their carefully orchestrated set of actions that leads to regeneration of the missing parts and therefore total recovery. A hard to heal or a chronic wound is deficient in these crucial growth factors essential for the healing process. Externally introduced growth factors under moist environment is one way of assisting this process, and this is where much research is currently in progress. Regranex(@produced by Johnson & Johnson is one such product that was first approved by FDA in 1998 for treating chronic diabetic neuropathic ulcers. It is made Erom genetically engineered platelet-derived growth factor and is applid as a topical gel. It actively stimulates the body to grow new tissues and aids the healing process. Clinical results have shown much improved recovery rates in diabetic patients sulTering Erom neuropathic foot ulcers. Hyaluronic acid has been recognised as an integral component of the extracellular matrix in the skin and underlying tissues influencing wound inflammation, cell migration, angiogenesis, re-epithelialization and scar development. HYM7), a biomaterial fibrdfleece produced by Advanced Biopolymers is based on esterfication of hyaluronic acid with different alcohols. It is used as a scaffolding base as well as dressings for diabetes and skin burn sufferers. This product is not only highly biocompatible but it is also biodegradable with proven ability to enhance tissue repair. Dressings containing fibroblast growth factors encapsulated in micro-spheres with the intention of prolonging growth factor release is another innovative approach to systematic tissue regeneration and hence healing. Tests on animals using these types of dressings have shown reduction in wound area and reasonable tissue/skin regeneration(’). Using genetically engineered human collagen, a new dressing that enables faster and improved healing has also been introduced. A more practical method however, includes mixing collagen with cellulose in the form of sheets or films.Known as Active Matrix Dressing, Promogran(’) produced by Johnson & Johnson takes advantage of the combined properties. Upon exposure to exudates, the active matrix forms a gel which, apparently, quells agents hostile to the healing within the wound and therefore speeds up recovery. Successful outcomes have been reported for treating pressure sores, leg ulcers and other chronic wounds. Another fairly recent technique of treating chronic wounds is known as VAC or Vacuum-assisted closure(’o).This method takes advantage of starving bacteria to death by cutting off the supply of air needed for its survival. This is usually carried out by inserting a foam dressing into the wound area armed with a drainage tube. The opposite end of the tube is attached to a vacuum pump whose action eventually kills the aerobic bacteria The vacuum action also removes necrotic and slough materials allowing the wound to close. Improved microcirculation leads to greater level of oxygen access to the tissues and hence recovery. This method of therapy can be highly effective if not very convenient. It is however, relatively expensive. 194 0 Woodhead Publishing Limited, 2010

Since the resurgence of old and traditional treatments where silver, honey and lava are prime examples, a variety of other techniques based on greater understanding of the body's physiological reaction to cuts and wounds have been developed with considerable successes. Electrical stimulation for instance, is a technique by which body's electrical activities are mimicked when an injury is received. Such simulations promote attraction of repair cells; alter permeability of cell membranes and influence cell structuring and secretion which ultimately leads to better healing. POSiFECT"" from Biofisica is a newly introduced bioelectric wound care dressing that delivers the current through a pad that sits on the wound face with an independent power source. Clinical trials on non-healing wounds using these products have paved the grounds for thcir wider availability. Improvement in blood circulation induced by high sound frequency is another method by which cells responsible for wound healing are believed to be stimulated during inflammatory and proliferative stages. These frequencies are generated in moisthydrogel based dressings in the wound area. Similarly, Whirlpool therapy(") is another method by which blood circulation and hence availability of oxygen to the wound area is increased leading to better healing. This technique however, is not suitable for wounds where excessive blood is present i.e. venous leg ulcers. The efficacy of both these methods is subject of further investigations. More recent methods of relieving pain and enhancing healing has included low-level laser therapy (LLLT) where red and near infrared light in the frequency range from 600 nm to 1000 nm produced by laser or light-emittingdiodes (LED) have been shown to be These research trials are ongoing. effective in treating chronic Based on the selection of examples referred to in this short overview, it is clearly evident that research in woundcare area (material or otherwise) is an ongoing process and will continue to develop as healing parameters and regeneration mechanisms are better understood. Based on these understandings, new materials will emerge that would combine natural and manmade materials more effectively to achieve better outcomes.

REVIEW OF PAPERS ON WOUND CARE MATERIALS Nanofibres intended for specialised applications are fast replacing micro-fibres given their enormous aspect ratio (widthflength) and high surface area. Their flexibility and conformation to particular shapes where seams, stitches and inconsistenciesare avoided are other reasons for their popularity. Electrospinning is one such technique where charged polymeric nanofibres are generated from application of high voltage and subsequently drawn across by electric field. The plenary paper submitted under this title reports on production of antibiotic loaded electrospun polyester fibres and examines the release mechanics of the antibiotic content and their potential effectiveness in killing bacteria over time. Odour from badly infected wounds causes extreme distress to the patients and anyone who comes in contact with them. The repulsive smells associated to these types of wounds are due to the volatile agents created by concoction of bacteridchemical byproducts undergoing metabolic processes. Inefficiency in performance criteria of existing products in containing these undesirable odours has focused researchers' attention to new and possibly novel methods of tackling the problem. The first paper in this series evaluates a selection of commercially available dressings containing activated charcoal for their acclaimed properties using a dedicated instrument and foresees the advent of better and more effective products through continuing research where identified problems associated to use of activated charcoal would be eliminated. 0 Woodhead Publishing Limited, 201 0 195

Since 1995, on average, over 35 new dressings have been added to the Drug Tariff every year, to the extent where today there exists over 400 brands of wound dressings each claiming unique or specific properties. Nurses and clinicians who are in the forefront of this influx are increasingly confused and on occasions are in disagreements with one another as to what dressing to choose and prescribe without hdermining patients’ welfare, safety and treatment needs whilst working within budgetary constraints of hospitals and the health service. The next paper highlights the need for a unified and a regulated approach based on collectivejudgement of panel of experts and its amalgamation with an expert system that would be available nationally. The paper reports on an initial survey involving primary care trust nurses and demonstrate the working principles of such an expert system. Targeted delivery of drugs, vitamins and other ingredients via encapsulation and hence localised dispensation is highly efficient, cost effective and neat way of treatingkhieving desired results. However, matlllfacturing methods, control of microcapsule size/uniformity and microcapsule shellhgredient compatibility are still subject of much research. The third paper in this series investigate the feasibility and effectiveness of microencapsulating cosmetic or medical fragrances such as rosemary oil and limonene in ethyl cellulose by phase separation method and their subsequent application onto cotton fabrics. The work concludes a direct relationship between produced microcapsule size and stirring speeds and confirms successful encapsulation of the fragrances via spectroscopic analysis. Ester bond formations between hydroxyl groups of cotton and that of ethyl cellulose are also verified. With increasing improvements in medical science and subsequent treatment efficiencies, patients’ expectations of general welfare and aftercare treatments have also increased. Today, patients expect to suffer l?om little or no pain, have scar free results following any minor or major surgery and to be as mobile as they possibly can. The fourth paper presented in this chapter acknowledges the need for compression garmentshandages whereby disfigurement and scar formation are prevented in bum injuries in particular, but questions the adequacy and effectiveness of current practices. It then introduces a new pressure monitoring machine which is claimed to have better but limited ability to monitor pressure changes at body/garment interface. Herbal medicine and ointments derived from natural sources have existed from very early history of human civilizations and numerous claims and counter claims are made with regards to their effectiveness. Psyllium husk is one such plant-based material that has traditionally been recommended for alleviation of various aliments including; diarrhoea, haemorrhoids, bladder problems, high blood pressure, cardiovascular disease, cancer, diabetes as well as dietary supplements. The final paper in this chapter reviews various aspects of this species and based on its inherent properties it highhghts its potentials for serious considerationin new areas including biomaterials. REFERENCES 1 A Heenan, Dressings on the drug tariff, World Wide http://www.worldwidewounds.com/l997/july/Heenan/T~.html

Wounds,

2 S Petrulyte, ‘Advanced textile materials and biopolymers in wound management’, Danish Medical Bulletin, Feb 2008 55( 1).


3 S C Anand, J F Kennedy, M Miraftab and S Rajendran, Medical Textiles and Biomaterials for Healthcare, Woodhead publishing Ltd, Cambridge, CRC Press LLC, Florida, 2006.

4 M Miratlab, Woundcare Materials, an overview, In Medical textiles and biomaterials for healthcure, Woodhead publishing Ltd, Cambridge, (S C h a n d , J F Kennedy, M Miraftab and S Rajendran (eds), Woodhead publishing Ltd, Cambridge, UK ,2006). 5 J Posnett, P J Franks, ‘The burden of chronic wounds in the UK’, Nursing Times, 2008 104(3) 44-45. 6 M Braddock, C J Campbell and D Zuder, ‘Current therapies for wound healing: electrical stimulation, biological therapeutics, and the potential for gene therapy’, International Journal of Dermatology, November 1999 38(11) 808-817. 7 L A Solchaga, J E Dennis, V M Goldberg and A L Caplan, ‘Hyaluronic acid-based polymers as cell carriers for tissue-engineered repair of bone and cartilage’, Journal of Orthopaedic Research, Feb 2005 17(2) 205-213. 8 C A Cochrane, C Shearwood, M Walker, P Bowler and D C Knottenbelt, ‘The application of a fibroblast gel contraction model to assess the cytotoxicity of topical antimicrobial agents’, Wounds, August 2003 issue 8.

9 Clinical Review, ‘A guide to the latest advanced wound care products’, Nursing & Residential Care, February 2006 8(2). 10 S Thomas, An introduction to the use of vacuum assisted closure, World Wide Wounds, May 2001, httr1://www.worldwidewounds.comJ200 1 lmaWThomasNacuumAssisted-Closure.html.

1 1 A Moody and K Baines, ‘Managing a non-healing pilonidal sinus with POSiFECT estimulation’, British journal of community nursing, 2008 12(12) S14, S16, S18 passim.1SSN: 1462-4753. 12 L Angelo Jr, Whirlpool therapy facility and method of treatment, US patent Office, Pat No 4291646, August 1999. 13 J T Hopkins, T A McLoda, J G Seegmiller and G D Baxter, ‘Low-level laser therapy facilitates superficial wound healing in humans: A triple-blind, sham-controlled study’, Journal OfAthletic, July 2004 39 223-229.


CONTROLLED DRUG RELEASE FROM NANOFIBROUS POLYESTER MATERIALS M J Bide (l), M D Phaneuf (2), T M Phaneuf(2) and P J Brown (3); (1) University of Rhode Island, Kingston, RI USA, (2) BioSurfms, Ashland, MA USA; (3) Clemson University, Clemson, SC USA

ABSTRACT Background Over 13 million medical devices are used annually in the United States, many of them based on fibrous materials, such as simple wound dressings, hernia repair mesh, catheter cuffs and to more prosthetic arterial grafts. All medical devices are prone to complications of infection, unregulated cellular growth, and undesirable blood clotting behavior. Currently available biomaterials do not emulate the dynamic biologic and reparative processes that occur in normal tissue to overcome these complications. Thus, a novel biomaterial for use in a wide range of medical devices to direct or enhance the normal healing processes of native tissue would improve patient morbidity and mortality. Goal

The goal of this study was to synthesize and characterize in vitro novel nanofibrous materials that contained biologically-activeagents such as antimicrobial, antifungal and antiseptic agents. Our hypothesis was that the nanofibrous materials would serve as a "reservoir", slowly releasing the active agents over an extended period of time. We employed electrospinning technology in order to synthesize the nanofibrous polyester materials. A major benefit of this process is that the polyester nanofibem are formed at low temperatures, unlike standard polyester fibers which are extruded as a melt at high temperatures. The low temperature permits the structure of the active compounds to remain intact, thus retaining their biological activity. Additionally, no exogenousbinder agents or polymers are required to incorporate the respective agents. Variation of drug concentration into the bulk polymer solution prior to electrospinning was also examined.

Evaluation of these drug-loaded polyester nanomaterials for drug release via U V M S spectrophotometry and subsequent biologic activity via specific biologic assay was performed for segments subjected to stringent washing conditions. These studies showed that active agent was released for an extended period of time (days to weeks) while maintaining activity upon release as compared to control nanofibrous polyester, which had no activity at any of the time periods examined. Activity of these surfaces was also controlled by the initial concentration loaded into the bulk polymer as indicated by our release and activity studies.


Conclusions This study demonstrates that biologically-activeagents can be individually incorporated into a nanofibrous polyester material. Additionally, these compounds are slowly released over an extended washing period. Lastly, these nanofibrous surfaces can maintain localized biological activity due to the drug elution fiom the nanofibrous material.

INTRODUCTION As recognized by the long history of this conference, textile materials are ubiquitous in medical devices. They are used in implanted (e.g. prosthetic arterial grafts, prosthetic valve sewing cuffs), percutaneous (e.g. catheters, sutures) and extra-corporeal (e.g. wound dressings, bypass pump tubing) devices. Depending on the use (in or out of the body, short or long term), these materials have limitations. They cannot modulate the body’s clotting response, which can lead to the blockage of blood flow in a prosthetic artery. Implants tend to remain “foreign”, which may lead to uncontrolled cellular growth at an artery&& interface (anastomotic intimal hyperplasia). Infection can occur as a result of bacteria attachment and growth to the textile substrate. Since the textile surface cannot combat this invasion, the healing of these materials can be adversely affected which can be fatal. A series of projects was begun more than a decade ago to deal with each of these problems as they affected prosthetic arterial grafts. These studies have resulted in numerous published papers and patents while broadening in scope to include catheters, wound dressings, masks and sutures. The work was based chiefly on taking an existing substrate (most often polyethylene terephthalate,polyester) and using established textile processes to modify the material surface. From these foundation studies, a “pad-heat” process was shown to provide polyester with long-lasting infection-resistance. Surface modification (hydrolysis or aminolysis) provided functional groups to which a range of bioactive proteins could be covalently linked while still maintaining activity. Using these modified surfaces, clot-prevention or promotion (depending on the end-use of the device) or cell growth-promotion properties (for prosthetic arteries) could be achieved. We have also shown that these effects could be combined, for example, to provide a wound dressing with both clot-promoting and infection-resistantproperties. While effective, these technologies have a number of limitations. The surface modification and subsequent crosslinking of proteins is a complex, multi-step process. The incorporation of antibiotics into preexisting polyester is limited to the substrate surface. The inclusion of antibiotic into the fiber during melt-spinning results in deeper incorporation but the antibiotic is “locked” within the substrate and unavailable for combating infection. The high temperatures involved in melt spinning could also denature bioactive proteins. Electrospinning has long been recognized but has recently become the focus of a considerable volume of research. A polymer solution is slowly extruded from the nozzle. A high voltage is applied to the polymer solution upon discharge from a small nozzle, which is then deposited onto a collector. The charged polymeric fibers are drawn across the gap to the collector by the electric field: as it does so, it is extended into low micron to nanometer-sized fibers.


r--

I

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I

An example of this process is shown

diagrammatically & Figure 1. The product that emerges can be varied by the control of several factors'. The first of these are the magnitude of the electric potential and the distance between the emitter and the collector. The s u r f m tension at droplet surface is also important, and is determined by the viscosity of the polymer solution, in turn elcctrospinning controlled by the solvent used, the molecular weight of the polymer, its concentration in solution, and the ambient temperature. Thus, there is considerable scope for the formation of subtly different materials. The potential of electrospinning has led to a rapid increase in research in this field over recent earsz294,including those investigating the formation of electrospun tubular structure^"^'7. For biomaterials, electrospinninghas been mainly confined to polymers such as polyurethane, PVA, PLGA, and proteins (e.g. collagen). These are typically of low strength and designed for dissolvable materials. Little has been reported on the electrospinning of polymers with more structural utility. Suture retention, bursting strength, breaking strength, tear strength and biodurability are critical to developing clinically useful implantabledevices. Polyester has been used in medical devices for over 50 years. Typical polyester fibers are formed through melt-spinning at temperatures of around 280°C with diameters of 15pm or more. Modified spinning methods have produced commercial polyester fibers with diameters ranging from 5-10 microns to low nanometers, but these still involve the use of high temperatures. In 2004, our group was the firstto electrospin polyester from solution at room temperature. The resulting material, comprised of fibers ranging in diameters h m IOOnm to 3000nm, possessed excellent physical and handling properties. We have published data showing that this material has qualities suitable for its use as a small-diameter prosthetic arterial graft8. Melt spun fibers are subjected to a hot drawing process to encourage polymer chain orientation and the development of crystallinity within the fibers. Electrospun polyester has been produced via melt spinningg, but in order to render functionality to the resulting matexial, gelatin was incorporated by subsequent surface m d i c a t i o n involving formaldehyde. This in turn improves physical fiber properties, but slows the diffusion of small molecular species within the fiber (thus, for example, undrawn polyester dyes more readily than drawn material). The shorter diffusion path out of fine fibers is responsible for lower color fastness of fabrics derived from them This study was conducted to examine the feasibility of incorporating an antibiotic into a solution of polyester to be used in electrospinning, and to examine the release of that antibiotic from the formed nanofibrous material.

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EXPERIMENTAL

As those who work in fiber analysis understand, polyester is not an easy fiber to dissolve. Our work was made possible by the availability of 1,1,1,3,3,3-hexduor0-2propanol (HFIP). This solvent dissolves a wide range of materials including polyester. 200 0 Woodhead Publishing Limited, 2010

The boiling point of HFIP is 60°C, so it is rapidly volatilized upon electrospinningas well as from the resulting nanofibrous material. As was used in much of our earlier work on incorporation of antibiotic into existing polyester substrates, Cipro was the antibiotic chosen for this study. Antibiotics vary in structural type, spectrum of activity, and clinical usefulness”. Cipro is one of the fluoroquinolones,a family of more than ten antibiotics and the drug of choice for many Quinolone antibiotics are chemically stable, and effective at low concentrationsagainstthe common clinically encountered organisms, particularly those bacteria responsible for biomaterial infection’3. These antibiotics also have structural features (solubility, molecular mass, and functional groups) that coincide with those of textile dyes and our previous work has shown that these similarities lead to the potential for dye-like interactions with polymeric materiall~’~”~”~. Polyester chips were procured h m Zimmer (O.63dUgy 0.15% Ti02, 23Oppm antimony acetate catalyst). A polyester polymer solution (19%w/v) was prepared in icecold 100% HFIP. This polymer solution was mixed on an inversion mixer for 48 hours. This solution was spun on a practical embodiment of the theoretical electrospiuningset up of Figure 1, shown in Figure 2. This , T- I system consists of a Glassman power supply, a Harvard Apparatus syringe pump, an elevated holding rack, a modified polyethylene chamber, a spray head with power attachment, a reciprocating system and a Wheaton stirrer for controlled rotation of a PTFEcoated stainless steel mandrel (diameter = 4m). A loml ChemiCal-resiStant syringe was filled with the polymer solution. A stainless steel 18-gauge blunt s p h ~(0*5mm t internal diameter) was cut in half. The two ends were , rip 2 ~ I e L t r o y m i i i i i y,ippiii‘itu\ remnnected via 66cm of Nalgene PVC tubing (1/32 ID X 3/32 OD). The syringe fitting end was connected to the polymer-filled syringe, and the tip was attached via an electrical contact to the reciprocating system. The line was purged of air, with the syringe then placed onto the syringe pump. The mandrel was positioned 15cm Grom the tip of the needle. The mandrel was then grounded to the power source. The perfusion rate was set at ~mvhourat 25°C. Perfbion of the polymer was then started upon application of the power to the tip of the needle (+15kV) with electrospinning proceeding for 40 minutes. After this time, the end portions of the electrospun tube (lcm &om each end of the mandrel) were cut offand discarded. The remaining segment was then stretched 25% of the starting segment size while on the mandrel in order to provide a set strain across the fibers, a process that occurs in normal fiber extrusion. Materials thus prepared (nPET) were then either air-dried at 6OoC overnight or exposed to 100% ethanol for 2 hours at room temperature in order to remove the residual solvent followed by air-dryingovernight at room temperature. Following experiments to determine the solubility of Cipm in HFIP, a 19% polyester solution containing 1.5% (w/v) Cipro was prepared. This polymer solution WBS electrospun in the same manner as the control nPET material. Materials were either airdried at 60°C overnight or exposed to 100% ethanol for 2 hours at room temperature in order to remove the residual solvent. 0 Woodhead Publishing Limited, 201 0 201

The materials prepared were tested in several ways. Tensile strength (poundsforce), strain at maximum load (“h)and strain at break (%) for a conventionalknitted polyester fabric (Type 54 standard material) and electrospun nPET material were measured using published techniques”. Electrospun material was examined via a JEOL JSM 5900LV electron microscope in order to determine fiber size and distribution throughout the material. The successful incorporation of Cipro into the fibers of the resulting material was qualitatively indicated by the fluorescent properties of Cipro. Material with and without Cipro exposed to 60°C overnight or to 100% ethanol for 2 hours, was examined under a hand-held U V light The release of Cipro from these tubular constructs was assessed via WMS spectrophotometry. nPET and nPET-Cipro materials (0.5cm length) were placed into 5ml of sterile phosphate buffered saline (PBS) followed by continuous agitation at 37°C. Wash solutions were sampled at acute (0, 1,4 and 24 hours) and chronic (2 - 21 days) intervals, with the wash solution replaced with a fresh 5ml of sterile PBS after sampling. The absorbance of wash solutions was read at 27Onm (PBS blank) using a Beckman DU640 U V M S spectrophotometer. A standard curve using known Cipro concentrationsranging from 0 lOOpg/ml was prepared. This Cipro standard curve was then used to extrapolatethe antibiotic concentrationwithin the wash solutions. The antibiotic activity of the washed materials was then assessed via a zone of inhibition assay. A stock solution of S.aureus was thawed at 37°C for 1 hour. This stock solution (1 pl) was added to 5ml of Trypticase Soy Broth (TSB) and incubated Overnight at 37OC. Using this overnight inoculum, l O p l was streaked onto TryptiCaSe Soy Agar (TSA) plates. Unwashed and washed nPET and nPET-Cipro segments were then embedded into the streaked TSA plates and placed into a 37°C incubator overnight. Staudard Cipro Sensi-Discs (5pg Cipro) were embedded at each time interval as a positive control. The zone of inhibition each piece was determined, taking the average of 3 individual diameter measurements. Zone size (mm) at each sample period was determined for each parameter evaluated.

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RESULTS The nPET tubular constructs, whether air-dried or exposed to ethanol followed by airdrying, had a consistent 4mm internal diameter throughout the length (average length = 7.5cm). Table 1. Physical properties of electrospun materials There was a marked difference between the break load of knitted polyester (42 f 9 pounds force) Knitted and nPET (3.7 f 0.9 pounds force) segments (Table 1). This 3.7 f 0.9 difference in breaking load was expected due to the significantly greater thickness of the knitted polyester material. The other physical properties such as the percent strain at maximum load and percent strain at break were comparable between the two materials indicating that the difference in break strength was directly related to wall thickness. Thus, the nPET material possesses physical characteristicsthat would permit application in various devices. Analysis of these nPET structures via SEM revealed that the diameter of the polyester fibers comprising the material varied f?om lOOnm to 300Onm (Figure 3). 202 0 Woodhead Publishing Limited, 2010

These fiber diameters were significantly less than those comprising knitted polyester material, which ranged from 15 to 30pm.

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Fig. 3 SEM image of electrospun material

Fig 4. Fluorescenceof Cipro-containing nPET material

Based on our perfusion rate in conjunction with electrospinning time, approximately 30mg of Cipro was dispersed across the total segment length. Gross observation of the revealed intense fluorescence fiom the GET-Cipro segments, whether airdried or ethanol washed, as compared to the nPET segments demonstrating the presence of Cipro within the polymer (Figure 4). The release profile from the Cipro-loaded material is shown in Figure 5. Cipro release within the first 4 hours was consistent at 5 f 2pg/ml followed by a sharp increase to 13 f 4pg/ml at 24 hours. Cipro release then decreased to 6 f 4pg/ml by 48 hours, but persisted (ranging from 1-2pdml) throughout the length of this study (504 hours). The release of Cipro was reflected in the qualitative and quantitative evaluation of antimicrobial activity. SET-Cipro materials had significantly greater antimicrobial activity than nPET controls at all of time periods examined (Figure 6). The lack of antimicrobial activity in the nPET controls, comparable to non-nanofibrous polyester controls in earlier studies, shows that no residual toxicity remaitls from the presence of HFIP solvent. The zone of inhibition by the 5pg Cipro Sensi-Discs was consistent at 23mm. The nPET-Cipro antimicrobial activity profile correlated with the Cipro release determined in the spectrophotometric studies in that the greatest antimicrobial activity occurred within the first 48 hours. Cipro antimicrobial activity, due to lower Cipro concentrations being released as determined by the spectrophotometry, decreased slowly over the remaining time periods. However, significant antimicrobial activity was still evident at 504 hours, with zones comparable to the Sensi-Disc results. Thus, this study demonstrated that Cipro release persisted for over 504 hours, with antimicrobial activity correlating to Cipro release. The results obtained show release of Cipro at a consistent and long-lasting rate, in excess of that obtained from conventional polyester materials with Cipro incorporated into the surface, or materials in which Cipro is included in the material prior to spinning. In the absence of concrete information concerning the morphology of these electrospun materials, it is postulated that the greater release is brought about by an amorphous structure, in combination with fine fiber diameters. 0 Woodhead Publishing Limited, 201 0 203

T

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Fig 5 . Cipro release from electrospun polyester over time

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2

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Fig 6. Antibiotic activity of electrospun polyester over time

Further work might establish the morphological characteristics of polyester spun in this way. Little work has been done to optimize this spinning process and changes in spinning parameters and/or post spinning drawing or annealing treatments might reveal even better results. Work is ongoing to examine the incorporation of other bioactive agents into the spinning solution, and the use of other polymers as substrates.

CONCLUSIONS Polyester can be electrospun at room temperature from solution in HFIP to produce a tine-fiber structure. Cipro can be added to the spinning solution and thereby incorporated into the final material. The Cipro is slowly and steadily released over an extended washing period. Development of a drug-loaded nanofibrous material with a slow-releasing antimicrobial agent has significant potential for use in medical devices such as wound dressings, catheter cuffs, repair mesh, prosthetic vascular grafts, sewing cuffs and the artificial heart, all of which have polyester components.

REFERENCES 1 J Doshi, D H Reneker, 'Electrospinning process and application of electrospun fibers', J Electrostatics, 1995 35 15 1.

2 R S Manley, US Patent Office,Pat No. 4 266 918, pulp and Paper Research Institute of Caaada, 1981. 3 M M H o b , G Shin, G Ruteledge, M P Brenner, 'Electrospinning, electrospraying and the instability of electrically forced jets', Part 1, Phys. Fluids, 2001 13 2221. 4 W J Li, E J Laurencin, E J Caterson, R S Tuan, F KKo, 'Electrospun nanofibrous structure: a novel scaffold for tissue engineering', JBiomed Mater Res, 2002 60 613. 5 D J Lyman, F J Fazzio, Synthetic Polymer Prosthesis Material, US Patent Office, Pat No 4 173 689,1979. 204 0 Woodhead Publishing Limited, 201 0

6 D Annis, T V How, A C Fisher, Recent Advances in the Development of Arrifcial Devices to Replace Diseased Arteries in Man: A New Elastomeric Synthetic Artey. In Polyurethanes in Biomedical Engineering, Planck H , Egbers G, Syre I (Eds), Elsevier Science Publishers B.V. Netherlands, 1984.

7 E Wong, et. al. US Patent Office, Pat No 4 475 972, 1984. 8 M D Phaneuf, P JBrown, M J Bide, F W LoGerfo, ‘Nanotechnology in cardiovascular devices: Development of a novel small-diameter vascular graft’, Proceedings, BioInterface 2004. 9 Ma et. al. Biomaterials 2005,26,2527 10 W Joklik, H Willet, Antimicrobial Agents, in Zinsser Microbiology -18th Edition, Joklik, W., Willet, H. Amos, D. (A), Appleton Century Crafts, 1984. 11 K Grohe, ‘Antibiotics-The New Generation’, Chemishy in Britain, 1992 28(1) 34.

12 M J Wood, ‘Therapeutic Focus: Cirpofloxacin’, Br JClin Prac, 1988 42 469. 13 A Fitton, ‘The Quinolones: An Overview of Their Pharmacology’, Clin Pharmacokin 1992 22(Suppll):l. 14 M D Phaneuf, C K Ozaki, M J Bide, W C Quist,J M Alessi, G A Tannenbaum, F W LoGerfo, ‘Application of the quinolone antibiotic ciprofloxacin to Polyester utilizing textile dyeing technology’, JBiomed Mater Res 1993 27 233. 15 C K Ozaki, M D Phaneuf, M J Bide, W C Quist, J M Alessi, F W LoGerfo, ‘In vivo testing o f an infection resistant vascular graft material’, JSurg Res, 1993 55 543.

16 M D Phaneuf, M J Bide, W C Quist, F W LoGerfo, Merging of Biomedical and Textile Technologies in order to Create Infection-Resistant Prosthetic Vascular Gra@s, in Anti-microbiaVAnti-infective Materials; Principles, Applications and Devices, Sawan, S.P. and Manivannan, G. (A), Technomic Publishing, Lancaster, PA. 17 M D Phaneuf, W C Quist, M J Bide, F W LoGerfo, ‘Modification of polyethylene terephthalate (Polyester) via denier reduction: Effects on material tensile strength, weight and protein binding capabilities’, JApplied Biomater, 1995 6 289.

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DEVELOPMENT OF ODOUR (VOLATILX MOLECULE) ADSORBENT MATERIALS FOR HEALTHCARE G. Lee', S. C. Anand', S. Rajendran' and I Walkel? Institute for Materials Research and Innovation, The University of Bolton, Bolton, BL3 5AB, UK * Lantor(UK)Ltd, Bolton, BL3 3PP, UK

'

ABSTRACT Wound malodour is rapidly becoming a critical issue, particularly with patients suffering with c h n i c illness that often result in wounds such as; venous leg ulcers, diabetic ulcers, pressure ulcers and hgating (malignant cancerous)lesions. The malodour is usually just part of the whole chronic situation but it can affect the patient in numerous social and psychological ways. There are specific wound dressings on 'Drug Tariff to treat malodour. These contain a layer of activated chacoal which facilitates the adsorbing of wound malodour. Although activated charcoal is efficient in the adsorption of volatile odorous molecules, there some issues with its use in wound dressings and these are: a) Activated charcoal cloth is black incolour; b) it is relatively weak in nature and can be easily ruptured and presents a risk of the broken hgments of carbon fibre contaminating the wound, if exposed; c) the efficiency of the ability to adsorb odorous volatile molecules is compromised if saturated with the molecular rich wound exudate; and d) activated charcoal cloth is relatively expensive to produce and this is often reflected in the cost of the final products. In order to address the above limitations, a research programme is in progess at the University of Bolton one of the objectives of this research is to investigate and develop a viable test method for evaluating the efficiency of odour adsorption, whilst researching and developing novel odourholatileadsorbent materials, to possibly replace the use of activated charcoal. To date there appears to be a dearth of quantitative comparable data on these specific wound dressings particularly on their odour adsorption efficiency; this may be due to the limitation of realistic test methods of evaluating this characteristic. Further research work has been carried out on a novel test method for odour adsorption that has combined the efficiency of odour adsorption together with the assessment of fluid handling capabilities. Although there still some criticisms with this method it appears to be the nearest, to date that simulates some of the physical conditions that the product would experience in use. A selection of currently available activated charcoal wound dressing products have been tested, evaluated and quantitative comparable data collected. Some natural polymeric antimicrobial agents have also been tested and evaluated for their potential d o u r adsorption efficiency. These results will enable us to develop, engineer and characterise a range of novel odour adsorbent materials by using innovative fibredpolymers, fabric structures and composites incorporating adsorptive and antimicrobialproperties.


INTRODUCTION Wound malodour is rapidly becoming a critical issue, particularly wih patients suffering with chronic illness that often result in wounds such as; venous leg ulcers, diabetic ulcers, pressure ulcers and fungating (malignant cancerous) lesions. The malodour is usually just part of the whole chronic situation but it can affect the patient in numerous social and psychologicalways. Wound malodour is due to the presence of necrotic (dead tissue and/or the result of severe colonisatiodiection of bacterial m i c r o - ~ r g a n i s m5 s).' ~These ~ ~ ~ malodorous microorganism are of the bacteroides and clostridium species, in a cocktail of different volatile agents, like n-butyric, n-valeric & n-caproic acids, amines and diamines such as cadaverine andputrescine, that are produced by the metabolic processes'*4p5. There are specific wound dressings on the 'Drug Tariff to treat malodour. These contain a layer of activated charcoal which facilitates the adsorption of the wound odour. Activated carbon is efficient in adsorbing these odoroudvolatile bacterial micrcmrganisms but it does not have bactericidal or bactaia-static characteristics, also there are some other issues with regard to its use in wound dressings, these are: a) Activated charcoal cloth is black in colour; b) it is relatively weak in nature and can be easily rupturedand presents a risk of the broken fragments of carbon fibre contaminating the wound, if exposed; c) the capacity of adsorption of adsorb odorous volatile molecules is compromised when saturated with the molecular rich wound exudate; and d) activated c h a m 1 cloth is relatively expensive to produce and this is often reflected in the cost of the final product To date, there appears to be a dearth of quantitative comparable data on these specific wound dressings, particularly on their odour adsorption efficiency; this may be due to the limitation of realistic test methods for evaluating this characteristic. Further research work has been carried out on a novel test method for odour adsorption that has combined the efficiency of odour adsorption together with the assessment of fluid handling capabilitie2. Although there are still some criticisms concerning this test method it appears to be the nearest simulation to some of the physical conditions that the product would experience in use. In this study, a selection of currently available activated charcoal wound dressing products have been tested, evaluated and quantitative comparable data collected. Some natural polymeric antimicrobial agents are also under investigationfor their potential odour adsorption. Ultimately the results from these evaluationswill enable us to develop, engineer and characterise a range of novel d o u r adsorbent materials by using innovative fibredpolymers, fabric structures and composites incorporating adsorptive and antimicrobialproperties. ODOURADSORBENT MATERIALS Activated Charcoal Cloth ACC The use of charcoal (carbon) in the adsorption of wound odour has been known from as early as 1550 BC, as depicted by the ancient Egyptians'. After in-depth research during the 1800's it was discovered that the potential adsorbency of the carbon rich matter can be increased by further controlled pyrolysis and therefore creating what is now known as activated carbon6. Carbon-rich regenerated cellulose viscose rayon fabric is used as the precursor for the activated charcoal cloth ACC, found in most of the currently available


odour adsorbent wound dressings. The viscose rayon fabric is subjected to a chemical p r s treatment followed by a sequence of controlled high temperature exposures in an atmosphere of nitrogen or more commonly carbon dioxide During the treatment the s&e area of the carbon matter (viscose fibres) vastly increases, this is in the form of small macro and micro pores (0.5nm and 0. Inm) creating highly amorphous porous fibres. This results in a carbonised material resembling the original viscose rayon knitted and/or woven fabric, although now black in colour and with a drastically reduced mechanical properties, therefore h g i l e to moderate physical forces. The odorous volatile micm organisms/ bacteria floral are attracted to the surface of the activated charcoal via intermolecularforces and on contact they become attached by a bond (Van der Waal force) which securely holds the offending odorous molecules in place entrapped w i t h the charcoal structure6. Although the known available surface area ofthis activated charcoal is immense making it highly adsorptive to micro volatiles, it is now known that the macro sized pore/sites can be prematurely saturated by the larg fatty acid molecules found in wound exudate compromising its odour adsorptive efficiency, one of the issues mentioned in the introduction.

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Alternative volatllelodour adsorptive materials Novel odow aakorbent textilefinishes

There are many new and innovative fibredyams, fabrics and textile finishes that offer antimicrobial characteristics, and now there is evidence that some also have odour suppressionladsorptioncharacteristics. Polysaccharide fibres such as; chitidchitosan and alginate plus some novel carbohydrate polymers (e.g. Branan ferulate)8 all with the potential of odour adsorptive characteristics. There are textile products containing novel ammonium zeolite and cyclodextrin finishes Zeolites are inorganic material that are similar to activated charcoal in having a highly microporous and mesoporous structure with the ability to adsorb volatile molecules. Cyclodextrins are polysaccharides with a molecular shape of six to eight D-glucose units, which fonn a bucket shaped molecules with a hydrophobic cavity. The cavity has the ability to attract and encapsulate volatildodorous molecules, plus they can store fragrant molecules or specific drugs that can be released0*". Cyclodextrins have now been introduced into an adhesive hydrocolloid woundcare product; the cyclodexh-ins have been chemically incoprated into the complex adhesive m a d ' . Textile finishes derived from copper and zinc are also under investigation into their odour adsorptive characteristics, for example, reactive dye molecules derived from copper salts, plus there has been recent research into deodorizingproperties of mordant as well as acid dyes". These novel odour adsorbent finishes have been initially promoted in active and sports apparel applications where as materials intended for woundcare require certain critical criteria's and specifications". The research is omgoing into tbese new novel finishes into eliminatingany rislds of toxicity, or leaching.

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Potential natural remedies

There are many old and ancient remedies with desirable anti-microbial characteristics as well as a history for use as alternative remedies in woundcare. There are animal-derived


products like; fish oils, sheep's wool &anoh, Silk cocoons)13and milk (as butter milk 8c live yoghwt as lactic acid)I4. Herbal extracts and balms for example; Calendula o#cinalis, Tannins (oak bark, witch hazel), tea tree oil (Melaleuca alternifolia), mem oil (Azadica hdica) and aloe vera (Barbadensis miller) 's,'6, plus sugar, sugar pastel7 silver and honey (Manuka)13J*. Some of these agents have recently been reintroduced into modem wound management particularly for treating difficult-to-heal wounds, for example; silver, honey (Manuka) and aloe vera. Laboratory studies have demonstrated that honey has a broad antimicrobial spectrum; a) it has the hyperosmotic characteristic of high sugar believed to inhibit bacterial growth, b) Acidity, and c) it contains low levels of antiseptic hydrogen peroxide. Man& Honey is a specific type of honey derived from bees bred on Manuka (Leptospermum scoperium (Myrtaceae)) plantations in New Zealand This has been shown to possess the best antimicrobial characteristicsof all other types of honeys evaluatedI9. Aloe Vera (Barbadensis Miller) as most of other natural remedies mentioned above is composed of polysaccharide. Polysaccharides have the potential for odour/volatile adsorption, but not all polysaccharides are the same. Aloe Vera is a complex plant containing many biologically active substances as well as polysaccharides. The gel polysaccharides in aloe vera are immune stimulatory or improve wound healing especially the acetylated mannans Aloe vera also contains many other beneficial ingredients like; vitamins, minerals, enzymes, sugars, anthraquinones or phemlic compounds, lignin, saponins, sterols, amino acids and salicylic acid Aloe Vera has also shown antibacterial and antifungal activity in laboratorytests 16.20. A selection of these old natural remedies is under investigation for their potential in adsorbing malodour. There is a growth of supportive scientific research and clinical data on the potential benefits of these possible alternatives.

EXPERIMENTAL WORK

Test method The description of the test apparatus is described elsewherd (Thomas et al 1998), and is shown in Fig 1. The apparatus comprises of a horizontal stainless steel plate rig, with a central circular recess of 5Omm diameter and 2mm deep. There is a small hole in which the volatile/malodoroustest solution is fed via a mechanical syringe pump. This is to simulate an exudating wound. The test solution consisting of sodium/calcium chloride solution containing 142 mmol of sodium ions and 2,5mmol of calcium ions as the chloride salts Cfie concentration of which is quoted to be comparable b human serum or wound exudate), 2% diethylamine (odorous volatile) and 1Oohnewborn bovine serum (fatty acids), simulating wound exudate.


Fig I. Novel efficiency of odour adsorption test equipment. (Courtesy of SMTL) A lOcm X lOcm test specimen (dressing) is then placed centrally over the mess and attached securely down each edge with a waterproof medical adhesive tape. The mechanical syringe pump is activated and the test solution is slowly introduced to the lower wound contact face of the test specimen. The stainless steel plate rig is fitted with an airtight Perspex chamber that is placed directly over the test specimen and the air in the chamber is monitored via a Miran 1B2 ambient analyser @Ispectroscopy),every 5 seconds for the detection of diethylaminevolatile. The collected data is converted into time/duration and volume of test solution in ml. The test dressing specimens are continuously monitored to assess any strikethroughand/or leakage of the test solution. For this study a selection of commercially available Activated charcoal wound dressings were assessed for their efficiency of odour adsorption. These dressings were CarboflexB ConvaTec, Lyofoam C@ SSL, Carboneto Smith & Nephew, Sorbsan plus carbon@ ConvaTec, Actisorb Silver@ Johnson & Johnson, ClinisorbOB CliniMed, Carbopad VC@ Vernon Carus, and a non odour adsorbent basic dressing MelolW Smith & Nephew as a Standard.

RESULTS The results of this study demonstrate the varying physical differences between the selected wound dressings assessed and average results are shown in Table 1. Two of the dressing types showed very low WVTR (Water Vapour Transference Rate) and air permeability. The Carbopad VCQ specimens showed very low/minimal air permeability, exhibiting an occlusive characteristic; this presented problems during the test to evaluate the efficiency of odour adsorption and was therefore withdrawn from this test. The fluid handling capabilities of a wound dressing product can influence its ability to contain the malodorous test solution and therefore delay the release of the volatiles/odours into the surrounding air. This was demonstrated by the basic wound


Table I . Average test results. WVTR Water Vapour Transference Rate (g md 24hr")

Air Permeability (cm3sec")

Average efficiency of odour adsorption (time in min to 15ppm ET2NH2) 20.19

Carboflex

4160

28 21

Fluid handle Absorption test (mi Iwcm'*) 42 98

Lyofoam C

2800

0 99

19 39

634

Carbonet

4640

13 02

45 56

10 23

Sorbsan with carbon

4640

17 36

40 14

11 32

Actisorb silver

6560

39 45

7 15

12 5

Carbopad VC

1600

0 07

7 94

N/A

Clinisorb

6560

33 93

10 01

8 56

Std Melolin

4967

26 43

34 23

404

Wound dressing

I

-

Acthiorb Silver Sorbsan with Carbon Carbonet

-:

Lyofoam~ 000

600

3 6 Yln Is eqwvalent l o 24

10.00

i5.00:

ZOfw

Time in minutes (showin

Fig 2. Range of results from the novel test method.

[lIIl

llllllal

absorplion

nange

01 n ~ r l up lake measured

A c l i ~ o r bSilver

[

borbsdfi willi Carbon

1 Maximum

capaaly of absorbence ( 0 s EN 13726 12002)

0

5

10

15

20

75

yl

35

1G

45

Y)

Fluid (ml)

Fig 3. Volume of test solution absorbed during testing.


dressing Melolin@ (Smith & Nephew), as it appeared to initially delay the penetration of the malodour through its fibrous construction.As expected, all the ACC dressings delayed the penetration of the volatiledodours for longer periods that the Melolin dressing with results ranging h m a minimum of 3 minutes to a maximum of 30 minutes. In a previous study by Thomas et al it was calculated that a leg ulcer can exudate at the rate of 0.Sml/cm2/24hr , the test solution was set at a rate of 36.7mVcm2/24hr therefore it was deduced that approximately 16 minutes in the test rig is equivalent to 24 hours in use. Overall, CarboflexB (ConvaTec) dressing showed the best results as regards the efficiency of odour adsorption, with recorded result times from 9 to 30 minute duration in the rig (estimated 13 to 45 hours in use). Actisorb@ Silver (Johnson & Johnson), also appeared to yield good results with a recorded duration time fiom 11to 16minutesin the rig (estimated 16 to 24 hours in use). None of the other ACC dressings reached the 16 minutesin the rig and therefore have a potential odour adsorption in use of less than 24 hours, see fig 2. During testing, it was observed that the test solution would often seek the easiest route of resistance, and in some of the dressing specimensthe test solution would leak out at the edges rather than penetrate through all the layep. For some of the highly absorbent dressings it was found that the test solution would prematurely strike through the multilayer, without using the dressing’s potential absorption capacity, see fig 3. This novel test method works on the principle of detecting the volatile (diethylamine) based on the penetration of the test solution by either strikethroughor leakage. Therefore,the ability of a dressing material to adsorb and retain the malodorous solution and yet maintain its other desirable characteristicsis required.

CONCLUSIONS

ACC is generally excellent as regards adsorbing volatile/odorous molecules, however as mentioned earlier it presents some limitations in its use in specialist wound dressings. Alternative products m required that offer additional antkmicrobial characteristics that will adsorb, entrap and kill the volatile bacteria causing the wound malodour. This is in addition to maintaining other desirable characteristics such as control of vertical wicking; retention of the absorbed fluid whilst maintaining a moist wound contact layer in order to promote wound comfort and healing. In order to seek possible alternatives to the ACC currently used, it is important to establish a quantitative test method. Therefore working in collaboration with the Surgical Materials Testing Laboratory (SMTL) Cardiff, UK,fUrther research into this novel method for evaluating both the odour adsorption and fluid handle will be carried out. To date this method appears to be the most efficient method of determining quantitative comparable data of different dressings both commercial and expenmend Textile fibre assemblies have a very large specific surface are@and therefore have the ability/potentialto attract, adsorb and diffusevolatile substances. With the correct selection of polymer /fibres, fabric structure(s) and their arrangement, combined with an appropriate selection of potential anti-microbial odour adsorbent agent@)an alternative to the currently available ACC wound dressings can be designed and engineered. No two wounds are alike and the demand for finding the ideal wound dressing is often confusing and difficult. The cause of the mund malodour is the main concern of the clinician, while the problem of the malodour is one of the top three concerns of the patienls and their quality of life. Therefore a better understanding of the physical characteristics of


dressings, as well as continued research and knowledge into the causes and treatment of the malodour are vital.

REFERENCES 1 P G Bowler, ‘Microbial involvement in chronic wound malodour’, Journal of Woundcare 1999 S(5) 216-218.

2 M Benbow, ‘Malodorous wounds: how to improve quality of life’, Community Nurse, 1999 5(1) 4 3 4 6 . 3 S Thomas, B Fisher, P Fram, M Waring, ‘Odour adsorbing dressings: a comparative laboratory study’, Journal of Wound Care, 1998 7(5) 246-50. 4 F Murray, ‘Malodour in diabetic foot wounds’, The Diabetic Foot, 2005 8(3)122-132.

5 K Williams, ‘Malodorous wounds: causes and treatments’, Nursing and Residential Care, 1999 l(5) 276-85. 6 J W Hassler, J. W. Activated Carbon: chemical & process engineering. London, Leonard hill 1967.

7 .IWildman, F J Derbyshire, ‘Macro porosity in activated carbons: its origins and functions’, Paper for Sutcliffe Speakman Carbons Ltd, Guest Street, Leigh, 1980. 8 J F Kennedy, C J Knill, ‘Biomaterials utilized in medical textiles an oveTViewy,3rdh t confMedica1 textiles and biomaterialsfor healthcare, Bolton UK, Woodhead, 2006.

9 K Takai, T Ohtsuka, Y Senda, M Nakao, K Yamamoto, J Matsuoka and Y Hirai, ‘Antibacterial properties of antimicrobial textile products’, Microbial Immunol, 2002 46(2) 75-81. 10 W D Schindler and P J Hauser, Chemical finishing of textiles: Novel finishes, Cambridge, Woodhead, 2004. 1 1 R D A Lipman, R.D.A. ‘Odour-adsorbing pressure-sensitive adhesives for medical applications’, Business briejng: medical device manufacturingh technology 2004.

12 Y Kobayashi, ‘Deodorizing properties of cotton fabrics dyed with direct dyes and a copper salt’, Textile Research Journal, 2002 72 125- 13 1 13 K Cutting, P Davies, ‘Natural therapeutic agents for the topical management of wounds’, Woundrr UK,2006 Mesitran Honey supplement, 4-1 3

I4 L B Welch, ‘Buttermilk & Yoghurt: Odour control of open lesions’, Reg. Nurse, 1981 44 42-43.


15 J Graf, ‘Herbal anti-inflammatory agents for skin disease’, Skin %ram Letter, 2000 S(4) 3-5.

16 M K Bedi, P D Shenefelf ‘Herbal therapy in dermatology’, Archives of Dermatology, Chicago, 2002 138 232-42. 17 H Gordon, et al. ‘Sugarand wound healing’, 7he Lancet, 1985 2 663-664 18 P C Molan ‘The role of honey in the management of wounds’, Jownal of Woundcure, 1999 8(8) 415-418 19 K L Allen, P C Molan, G M Reid ‘A Survey of the antibacterial activity of some New Zealand honeys’, JPharm Phannacol, 1991 43 817-22. 20 P Atherton, ‘Aloe Vera: magic or medicine’,Nursing St&d,

1998 12(41) 49-54.


DEVELOPMENT OF A DECISION SUPPORT SYSTEM FOR DETERMINATION OF SUITABLE DRESSINGS FOR WOUNDS K. G. Karthick’, M. Miraftab’ and J. Ashton’, ’Institute for Materials Research and Innovation,Universityof Bolton, Deane Road, Bolton BL3 S A B , UK 2BoltonPrimary Care. Trust, Bolton, BL1 IPP,UK

ABSTRACT Given the increasing autonomy of nurses in delivering patient care. and wound care management in particular, they are more than ever engaged indecision making associated with the assessment and treatment of wounds. To select and administer the ‘%ght” dressing from a wide variety of wound dressings available is not an easy task. There are. currently over 650 brands of wound dressings to choose fiom, but it is even more difficult because no one dressing suits all wounds and the choice is dependent on the cause of the wound and will be influenced by the presence of infection, the state of the individual’s health, the nurses prior and existing knowledge of wound care, availability of products and cost. Because of these complexities, nurses are becoming confused regarding wound care practice and research shows that in 85% of cases nurses are using inappropriate dressings and have difficulty in applying their theory and knowledge to their practice. This confusion leads to over consumption o f wound dressings thus increasing the c o d and perhaps more importantly increasing the valuable nursing time required. This web based project aims to optimise the usage of such resources, especially the nursing time available, by reducing the above 85% by developing an evidence based decision support system which would bring together the wound dressing selections made by the nurses from various geographic locations, after being peer reviewed by different tissue viability nurses. It will eventually use an expert system to suggest a choice of wound dressings for a particular wound from the information provided and based on the dressings already selected with the given criteria. It will also provide a comprehensive guideline to wound care and will have an important role as a learning package for student nurses and health workers within wound management. This paper will discuss the methodology used to design such adecision support system. INTRODUCTION Wound management is an ongoing treatment of a wound, by providing appropriate environment for healing, by both direct and indirect methods, together with the prevention of skin breakdown. Proper Management is determined by the wound’s size, depth, severity and location over the care period This management is changing rapidly due to the advancement in technologies which is shedding more light onto the aetiology of the wound and its healing process’. Nurses play a crucial role in the management of wounds They need to have good current knowledge and be more aware of their own wound care practices so as to bring about more effective wound management Nurses are the ones who take care of every single aspect of the patient right from record keeping, prescription handling to basic first aid. They have direct impact on the patients.


Wound care management is becoming more complex for nurses due to new insights into wound healing and because of the wide variety of w m d dressings that are available Erwin-Toth and Hocevar (1995) stated that there w r e approximately 400 brands of wound care dressings on the market to choose from and that wound care is made even more difficult because no one dressing method suits all wounds and the choice is dependent on the cause of the wound, infection, favourability and cost (Findlay, 1994). Because of these many different wound care techniques and dressings, nurses are becoming nonplussed regarding wound care practice. Alarmingly, Millers (1994) research showed that in 85% of cases nurses were using inappropriate dressings, and O'Connor found in her studg on wound care that nurses were having difficulty in applying their theory and knowledge to their practice. The results of the study taken by Barlow to find who selects the product used in the management of leg ulcers indicate that 53/57 (93%) district nurses and 33/43 (77%) practice nurses perceive themselves as always or fbquently making the decision. The perception that the majority of GPs never or rarely make this decision was shared by 54 (95Y0) district nurses and 30 (70"h)practice nurses. These results suggest that, for this sam ple, nurses perceive themselves to be the decision-makers on most occasions? Similar study conducted by Boxer and Maynard revealed that registered nurses had significant role in chronic wound management and that their decisions were mostly based on their own experience and that of their colleague$. Another part of this study also suggests that nurses are not using the best available evidence because of inaccessibility of resources and lack of time to search the literature. Nurses also cited difficulty in discriminating between a biased presentation and reliable research. Nurses are basically not accessing the best information that is available to them. They are relying on the nursing colleagues for advice and it also appears that ironically, their colleagues are not accessing the most reliable and conclusive information? In fact nurses in all specialities regularly make clinical decisions on direct patient care, but lack clinical decisions in supervision, management and extended roles! There were also differences in the decisions made between nurses in critical care and other areas of nursing.

RESEARCH AMONGST NURSING STAFF As of 2003, there were 386,359 nurses in the UK. Even 1% representation would mean 3864 nurses and with 301 Primary Care Trusts (PCT) in the United Kingdom (UK) (as of April 2004) we would need at least 13 responses from each PCT. If the sample population was to be reduced to just the tissue viability nurses, nurses from various PCTs from different parts of the country, could be selected with sample of 10 tissue viability nurses from each county. With 39 counties in the UK, this would lead to 390. This would in no way be a representation of the whole nursing population in UK but could still be sufficient representation of the nurses who are active in wound care services. However, the time limit and financial constraints associated to these kinds of activities are not always in favour of such investigation. For this reason convenience sampling was used and carefully designed questionnaires were sent to different PCTs in which at least one of the nurses was known directly or indirectly.


The prime objectives of the questionnaires were: 0 To identify the factors responsible for selection of wound dressings; 0 To identify the resources that were used to select a wound care product To find out whether they, the wound care nurses, would find it helpful to access the wound care information in a single place; and To find out whether they would be willing to use a computer aided decision making tool even if it might be time consumingto begin with.

Survey results The sample target was set at 100 respondents and a total of 175 questionnaires were sent out by post and few were given out in person. The total number of respondents were only 44. The results were consequently consolidated and analysed using the 44 received responses. No further attempts were made to reach the sample target due to time restrictions. The study showed that 73% (32) of the respondents refer to journals and British National Formulary and 20% (9), some of which (5) included in the above 32, also sought the opinion of their senior members of staff or their colleagues. Only 11% (5) of the respondents used the internet and only two mentioned that they did not use the internet because they did not have access to that resource. The most frequently referred resources were the wound care formulary and the nursing journals. When asked whether they would avoid referring to any of the resources because of the amount of time it consumes, 77% (34 out of 44)gave negative replies. Almost all the respondents except one agreed that they would like to have all the relevant information that helps them in making a choice to be available in a single place. 70% (3 1) of the respondents preferred to have them as a website even though only 11% admitted using the internet. Another 11% (5) apart from the 70% preferred both the website and a CD-ROM while 18% chose just the CD-ROM. The respondents who claimed to have used the internet for research have all preferred to have it as a website and they were either a grade E or grade F nurses. 93% (41) of the respondents expressed interest in using evidence-based decision support system to make a choice, if available. Two respondents said that they would not give it a try. 25 out of the agreed 43 (56%) mentioned that they would use the decision support system regularly and 18 of them said they would even if it was time consuming to being with. The other 44% (18) agreed to use them only when it would be difficult for them to make a decision on the choice of the dressing.

THE NEED FOR A DECISION SUPPORT SYSTEM Shared decision making between doctors and patients is an issue where computer systems may develop an important rule? Cost effective and appropriate care of chronically wounded patients is an outcome that must be attained in the near future as the number of people affected by chronic wounds burgeons in the next 20 years. Algorithms, decision trees, critical pathways, and computer software that include these processes may make this goal possible.


In wound care alone, there are a number of guidelines in which most of the recommendations are based on very little evidence. This is largely due to the lack of high qualiq randomized controlled trials (Dickson 1996, Renvoize et al, 1997, Haycox et al 1999) . The financial and human cost of pressure ulcers and other wound care conditions is high. Inappropriate wound management can have adverse affects on the healing process and is a waste of precious resources. Thomas and Bale et af have also highlighted variations in the cost of wound management dressings, underlining the importance of appropriatetreatment. The current emphasis on the use of evidence to support clinical interventions has entered a new phase with the establishment of the National Institute for Clinical Excellence (NICE).One of the early issues that are being addressed by NICE is the prevention of pressure sores, which will add considerablytothe body of knowledge about tissue viability. One of the key problems for NICE and other review groups is how best to disseminatetheir findings and recommendations to practitioned. The philosophies behind NICE, Commission for Health Improvement (CHI) and clinical governance are to make real improvements in clinical care - to iron out differences in practice between geographical areas, to implement best practice and eradicate outdated methods, and to make the whole system more accessible and a patient-fiiendly ex rience. Sir Muir Gray’rDirector of Clinical Process, Knowledge Management and Safety at Connecting for Health (CM, formerly the National Programme for Information Technology), has said: “Computerised decision support systems have the potential to support clinicians through the combination of computing technology and upto-date clinical research and information.”

EXPERT SYSTEMS IN MEDICINE Expert systems, as defined by the encyclopaedia, are programmes made up of a set of rules that analyze information (usually supplied by the user of the system) about aspecific class of problems, as well as provide analysis of the problem(s), and, depending upon their design, recommend come of actions in order to implement corrections. In layman’s terms, Expert Systems are computer programmes that are built to perform at a human expert level in a narrow, specialiseddomain. In medical terms, Medical Expert Systems are described as active knowledge systems which use two or more items of patient data to generate casespecific advice (Medical Informatics: Computer Applications in Health Care Shortliffe & Perrault). Although extensive evidence has highlighted the difficultiesencounteredin implementing paper-andpencil practice guidelinesand algorithms, many studies have shown that computerized systems have the potential to overcome these constraints, resultingin improved physician use and patient outcomes’ One such system is the Health Evaluation through Logical Processes W L P ) system, which is the longest running and most successful clinical information system Concepts developed with the HELP system have shown that:

’.


a) Clinical care can be provided with such a system. b) Computerized decision-support is feasible. c) Computerized decision-support can aid in providing more cost-effective and improved patient care; and d) Clinical user attitudes toward computerized decisionsupport are positive and supportive.'2

Evidence for feasibility of a decision support system Decision Support Systems @SS) are clinical consultation systems that use population statistics and expert knowledge to offer redtime information for clinicians. There have been a number of studies that has proved Clinical Decision Support Systems (CDSS) improve practitioner p e r f o ~ ~ ~ ~ ~ ~ c e ~ ~ . A computerised decision support system, for the management of stroke patients, that incorporated the findings of 960 Markov models examining the decision to prescribe as irin in the secondary prevention of stroke, was developed, and evaluated by Short D et alp4' using 15 GPs from the west Midlands. It was found that the GPs were more certain of their decision making and were more inline with the national guidelines It was suggested that the system made decision making easier, improved feelings of being supported, improved the quality of decision making and increased satisfaction. Tele-health has already been proved as golden opportunity to enhance quality wound care, improve availability, reduce costs, and provide outcomes datak5. A pilot study has proved that there is no difference between the healing times of foot ulcerations that were managed through telemedicine and diabetes foot prognurme groupsk6. Another pilot study which compared telsassessment with live assessment of pressure ulcers in a wound clinic has come out with the result that 89% of the assessor 's have agreed that telsassessment compared well with in-person assessment. This shows the potential accuracy of digital image and photographs in the diagnosis of patient conditions". Many of the previous research work show that guidelines disseminated through traditional educational interventions have minimal impact on physician behaviour. Providing focused training to key people in a practice and supporting subspecialisation through computer decision support may be a more appropriate approach to chronic disease managementin primary can?'. A 2-year project carried out in Canada to evaluate the use of multi-component, computer-assisted strategies for implementing clinical practice guidelines Evaluation indicated an increase in knowledge relating to pressure ulcer prevention, treatment strategies, resources required, and the role of the interdisciplinaryteam." In a randomised controlled trial, Tiemey et al (1993) demonstrated that patients treated by physicians who used a Personal Digital Assistant (PDA) containing decision support, which included costs of specific drugs and diagnostic tests, had less expensive hospital stays. Extrapolation of the cost savings due to reduced costs per admission was in the order of $3 million for the teaching hospital.

Internet as a tool for a decision support system The Internet having evolved as a potentially useful tool for guideline education, dissemination, and implementation because of its open standards and its ability to provide


concise, relevant clinical information at the location and time of need two clinical DSS's based on national guidelines were developed by Thomas EW et a t o and published on the Internet and both systems improved physician compliance with national guidelines when tested in clinical scenarios. By providing information that is coupled to relevant activity, it is expected that these widely available DSS's will serve as an effective educational tools to positively impact physician behaviod' . Already a web based Critical pathway is being used for radical nephrectomy which has improved health outcomes b reducing the hospital stay and admission charges and by improving the quality of care' Y. The NICE and CM are already undertaking a pilot study to develop and pilot methods for evaluating computerised decision support systems (CDSS). This project is to find whether any existing NICE methodologies such as Technology appraisal progamme could be applied to the evaluation of the CDSS.

DECISION SUPPORT SYSTEM FOR WOUND DRESSING SELECTION Evidence shows that a decision support system has contributed a great deal to the medical field. So an appropriate decision support system is requhd which can collect the data from different trusts. Internet is the commonly available, inexpensive media that is accessible h m any geographic location. So the DSS should be web based. The other advantages of hacng a web based solution are: a) All the information is available fiom a single source. b) All the information can be accessed and updated from any location. c) It can be peer reviewed from any part of the world. In the survey some have stated that they don't have access to the internet in their trusts only to intranet. But current technologies permit the users, through the configuration of a firewall, to access particular sites. The website can also be used as a leaming package where the wound care related materials can be accessed. It can act as a wamd care guideline which concentrates more on the selection process and its description rather than the current research that are being carried out in that particular field. Considering the above, increasing use and availability of internet, a website is being developed which will be carried out in two stages. This paper focuses on the decision support system rather than the learning package. The proposed functional operation and model of the decision support system after its completion is shown inFigures. 1-3.


Fig 2 Library of possible wounds

LIB I Wound location guide

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Fig 3 Typical wer interface page

The user identifies the location of the wound on the software system depicting full body figure and is presented with an array of possibilities in terms of wound type, size, depth, age etc. and amount of excaudate excretion, pain leveland so forth. Once the user has entered the requested data, the procedural route follow the decision support system as depicted in Figure 4.


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Fig 4. Proposed Model ofthe Decision Support System

The users have to login into the system in order to use it. The users are split into 2 user p u p s . The first being the nurses and the second being the peer reviewers who could be experienced specialist nurses or even doctors. The information that is entered by the nurses is stored as Extensible Markup Language (XML) files. XML is a set of rules for defining semantic tags that break a document into parts and identify the different parts of the document. It is a metrtmarkup language that defrnes a syntax in which other domain-specific markup languages can be writtea XML Applications are developed using this XML for a specific domain with its own semantics and v~cabula$~. Some of the well known Applications are Chemical Markup Language (CML) for Chemistry, Gedh4L for Genealogy, Mathematical Markup Language (MathML) for mathematical equations, MusicML for Musical Applications, etc.


The role of the deciaion support system

The main role of this decision support system is to collect the various characteristics of the wound and the dressing selected for that particular wound. Once a large database starts to build up, subsequent users can enter the characteristicsof the wound andobserve what type of wound dressing were selected for similar wounds. The DSS software will generate the results based on the number of such matched wounds and give a total number of times each type of particular dressing were selected. If a decision is made, then that decision is also added to the database thus updating the DSS accordingly. The role of the reviewer

For each entry that is being made into the system. A reviewer has to aprove that the information provided is true. A reference to the evidence used may be attached so that it helps the reviewer to approve quickly. If the reviewer thinks that the choice made is inappropriate, helshe may reject it from being entered into the llain database server and can state a reason as to why it was rejected and send it back which can then be viewed by just that particular nurse. Provision can be provided where the nurse can attach more evidence and send it for reconsideration. Advantages of the DSS

The main advantage of this system is the integration I accumulation of the nationwide wound care information in a single location. Such information helps in making a decision for selection of appropriate wound dressings It acts as a comprehensive database for wound care research. Since the decision support system is integrated with a learning package which is more of a wound care guideline than a latest news provider,it can be used to train staff as well as assist them with their professionaljdgement. CONCLUSION

In this research, the issues concerning the management of wounds by the nurses were reviewed and possible solution to the selection of appropriate wound dressings for given wound type was identified. The solution being a web based decision support system that helps to identi@ the appropriate wound dressing for a given wound. A nationwide survey was conducted to find out the feasibility of such a system and 96% (43) of the respondents showed interest in such a system. The paper also discussed the need for Decision Support System and the methodology and technology with which such a web based decision support system is being developed. This DSS, once fully developed, aims to reduce the confusion among the nurses in selecting appropriate wound dressings and also serve as a comprehensive guideline to wound care management.


REFERENCES 1 C Dowsett, ‘Developing wound management guidelines for community nurses’, British Journal of Community Nursing, 2002 7(2) 62-68.

2 B M King, ‘UK Wound management; Nurses’ knowledge; Research studies’, Journal of Wound Care, July 2000 9 0 343-346. 3 I Barlow, ‘Prescribing for leg ulcers in general practice, Part 2, Journal of Wound Care, Sep 1999 8(8) 390 - 393. 4 E Boxer and C Maynard, ‘The management of chronic wounds: factors that affect nurses’ decision-making’, Journal of Wound Care, Sep 1999 8(8) 409 - 412.

5 I Barlow, ‘Prescniing for leg ulcers in general practice, Part P, Journal of Wound Care, Aug 1999 S(7) 369-371. 6 N A Bakalis and R Watson, ‘Nurses’ decision making in clinical practice’, Nursing Standard, Feb 16 2005 19(23) 33-39.

7 BC Delany, DA Fitzmauricc, A Riaz and R Hobbs, ‘Can computerised decision support systems deliver improved quality in primary care?’, BUI, Nov 13 1999 No 3 19,1281. 8 A Tong, ‘Clinical Guidelines: Can they be effective? Amanda Tong questions, NT Plus, Mar 200 1 97(9) Pg III - IV. 9 J Unsworth and H Boon, ’Developing Internet based wound care information’, British Journal of CommunityNursing, 1999 4(9) 426-435. 10 The New NHS: Modem, dependable, Department of Health, The Stationery Office, London, 1997. 1 1 R B Elson and D P Connelly, ‘Computerized patient records in primary care: Their role in mediating guideline-driven physician behaviour change’, Archives of Family Medicine, 1995,4,698-705.

12 P J Haug, B H Rocha and R S Evans, ‘Decision support in medicine: Lessons fiom the HELP system’, Int JMed Inj Mar 2003 69(Iss 2-3) 273-284. 13 A X Garg, N K Adhikari, H McDonald and M P RosasArellano, ‘Effects of computerized clinical decision support systems on practitioner performance and patient outcomes: A systematic review‘, The Journal Of The American Medical Association, Mar 9,2005 2 9 3 ( I ~10) ~ 1223-1238.

14 D Short, M Frischer andJ Bashford, ‘The development and evaluation of a computerised decision support system for primary care based upon ‘patient profile decision analysis’, Informatics in Primary Care, December 1,2003 11(4) 195-202.


15 V J Ablaza and J Fisher, ‘Wound care via Telemedicine: The wave of the fitme’, Home Healthcare Consultunt, 1998 5(8) 12- 16. 16 W A Wilbright, J A Birke et al, ‘The use of Telemedicine in the management of diabetes-related foot ulceration: A Pilot study’, Advances in Skin and Wound Care, 2004 ISS 17,232-278.

17 P E Houghton, C B Kincaid, K E Campbell, M G Woodbury and D H Keast, ‘Photographic assessment of the appearance of chronic pressure and leg ulcerd, Ostomy Wound Management, 2000 46(Iss 4) 28-30. 18 Eccles et al’s Editorial Letter, B W , Feb 2003, No 326,394. 19 H F Clarke, C Bradley, S Whytock, S Handfield, C Van Der Wal and S Gundry, ‘Pressure ulcers: Implementation of evidencebased nursing practice’, Journal of Advanced Nursing, 2005 49(Iss 6 ) 578-590. 20 K W Thomas, C S Dayton and M W Peterson, ‘Evaluation of internet-based clinical decision support systems’, Journal of Medical Internet Research Oct - Dec 1999 l(Iss 2) E6. 21 J H Wandersee, ‘Concept mapping and the cartography of cognition’; Journal of Research in Science Teaching, I990 27( 10) 923-936.

22 P L Chang, Y C Li and S H Lee, ‘The differences in health outcomes between web based and paper-based implementation of a clinical pathway for radical nephrectomy’, BJU International, 2002 90 522-528. 23 M Leventhal, D Lewis and M Fuchs, Designing XU5 Internet Applications, New Jersey, Prentice Hall PTR, 1998.


TREATMENT OF COTTON FABRICS WITH ETHYL CELLULOSE MICROCAPSULES R. Badulescu', V. Vivod2,D. Jausovec2and B. Voncina* 'University of Ploiesti, Romania 2Universityof Maribor, Textile Department, Slovenia ABSTRACT Microencapsulation is a process, which enables a controlled loading and releasing of active substances In textiles, the major interest in microencapsulation is currently in the application of durable fragrances, skin softeners, phase-change materials, antimicrobial agents and drugs delivery systems. The capsules can be applied to fibers as dispersion with a binder, using padding, spraying, impregnation, and exhaust or screen-printing techniques. In our research, EC (ethyl cellulose) microcapsules containing essential oils were prepared by phase separation method. Essential oils such as rosemary, lavender, and sage were microencapsulated for odor control applications; they have sedative, antibacterial and deodorant properties. The surface of the obtained EC microcapsules was smooth. The size range of the microcapsules depended on the stirring speed employed in encapsulation (350-1000 rpm). Reducing the stirrer speed increased the size of microcapsules. The oil presence in EC microcapsule has been proved by vibrational spectroscopic analysis after microcapsules dissolution in acetone or after sonication in cyclohexane. The obtained EC microcapsules were grafted onto cotton fabrics using 1,2,3,4 butanetetracarboxylic acid (BTCA). To reduce the temperature of grafting two catalysts, cyanamide and N,N'-dicyclohexylcarbodrbodiimide were used. Scanning electron microscopy was used to study the linking of microcapsules onto textile substrate and Fourier Transform Infiared spectroscopy were involved to study the formation of ester bonds between hydroxyl groups of cotton and hydroxyl groups of EC via BTCA.

INTRODUCTION In textiles, the major interest in microencapsulation is currently in the application of durable fragrances, skin softeners, phase-change materials, and antimicrobial agents [11. The preparation of microcapsules from ethyl cellulose (EC) has been reported in the literature using various methods such as phase separation, coacervation, solvent evaporation, either by addition of a non-solvent, or of an incompatible polymer [2-51. The morphology of the microcapsules greatly depended on the solvent system [6].The viscosity and concentration of EC as a wall former, ratio of EC and active ingredient, and concentration of emulsifier also influenced the properties of microcapsules [5]. Zandi and coworkers [3] studied the effects of particle size, encapsulation efficiency and morphology of different molecular weights of EC. In our research, cotton fabrics were treated with EC microcapsules containing essential oils such as Rosemary oil or limonene. Rosemary oil is used in aromatherapy and in medicine for its antibacterial and antifungal properties. Limonene is the main component of the essential lemon oil; it is widely used in perlimes and cosmetics.


EXPERIMENTAL Materials Ethyl cellulose (EC) was purchased fiom Aldrich (viscosity 4 cP, 5 % in toluene/ethanol 80:20, extent of labeling: 48% ethoxyl). Rosemary oil was provided from Etol, Celje, Slovenia. R(+)limonene (95% sum of enantiomers) was used fiom Fluka. All other chemicals were of analytical reagent grade. Pure cotton with a mass of 140 g/m2 was used after it was first desized, scoured, bleached and mercerized on continuous production equipment.

Preparation of ethyl cellulose microcapsules EC microcapsules containing limonene and Rosemary oil were prepared as reported in patent [4]. 0.5 g sodium lauryl sulfate dissolved in 50 ml tap water was saturated with 6 ml of ethyl acetate. The pH of the aqueous phase was adjusted to 3. An organic phase was prepared by dissolving 0.7 g oil and 0.3 g ethyl cellulose in 5 ml of ethyl acetate. The resulting organic phase was poured into the previous aqueous phase under magnetic stirring. 100 ml of water was then added to the emulsion to induce diffusion of the organic solvent into the aqueous solution. After microcapsules were formed during a period of about 3-10 minutes, they were filtered on 0.45 pm diameter pore, washed by water and dried at room temperature. They were stored at 20°C. Blank microcapsules were prepared in the same manner with no oil added.

Determinationof oil content in ethyl cellulose microcapsules EC microcapsules containing oil were poured into cyclohexane and ultrasonicated for 1 min to extract the oils. The suspension was then filtered through a 0.25 pm filter to separate EC microcapsules. The limonene content was determined by FT Raman Spectroscopy. Each determination was carried in triplicate. FT-IR analysis gave qualitative information regarding Rosemary oil content in EC microcapsules. Thus, the 1730 cm-’ band was monitored. FT-Raman spectra were carried out using Perkin-Elmer spectrometer equipped with Nd:YAG laser source. Spectra were accumulated fiom 64 scans at a resolution of 4cm-’. An optical bench alignment was performed before each Raman measurements to ensure that the spectrometer was fine-tuned and the detector signa.l maximized. FT-IR spectra were recorded using Perkin-Elmer spectrometer equipped with diamante crystal for attenuated total reflection (ATR). The FT-IR or Raman spectra were smoothed and their baselines were corrected using the “automatic smooth” and the “automatic baseline correct” functions of the built-in software of the spectrophotometer. Then, the intensities of the interested peaks were measured. Scanning electron microscopy (SEM) was performed using PHILIPS XWOESEM scanning electron microscope after the microcapsuleswere coated with gold.

Treatment of cotton fabrics with ethyl cellulose microcapsules EC microcapsules were linked onto cotton via grafting with 1,2,3,4butanetetracarboxylicacid (BTCA). The mercerized cotton was immersed in treatment baths with different concentrations of EC microcapsules and B’TCA; for reduction of curing temperature the catalysts cyanamide (CA) and N,N’-dicyclohexylcarbodiimide 0 Woodhead Publishing Limited, 201 0 227

@CC) were used [7]. The wet pick up was 100%; the cloth was predried at room temperature for 24 hours and cured at llO°C for 20 and 2 minutes respectively when CA was used. When DCC as a catalyst was used the thermofixation was omitted, the esterification was expected to occur at room temperature. The treated textile material was rinsed in cold water. The weight gain of the finished fabrics was measured. The samples were dried for 4 hours at 105°C and weighed before and after finishing.

RESULTS AND DISCUSSION Preparation of ethyl cellulose microcapsules EC microcapsules containing Rosemary oil or limonene were obtained by phase separation method. According to this procedure, EC microcapsules without oil could also be produced. This could be explained due to EC interfacial activity, which stabilizes the formed emulsion. Surfactant-fiee multiple emulsions using EC as a polymeric emulsifier have already been reported by Melzer and collaborators [S]. From the scanning electron micrographs shown in Fig. 1 it is observed that EC microcapsules had regular spherical shape, the size of microcapsules varied and that the surface was porous. The size and degree of sphericity of the microcapsules depend on the stirring speed employed in encapsulation (see Table 1). Reducing the stirrer speed increased the size of microcapsules. Lower stirring speed provided microspheres with slower release rate of oil. This could be explained by an increased resistance of the dispersed phase to size reduction, since the viscosity of the dispersed phase increased as the stirring speed was reduced [9]. The yield of microencapsulation was measured by comparing the total weight of the microcapsuleswith the combined weight of the polymer and oil.

Fig. 1 SEM micrographs of EC microcapsules containing limonene oil (The stirrer speed was 350 rpm).


Table 1. Influence of the stirrer speed on yield of microencapsulation and microcapsule diameter Oil Stirrer speed, Yield, Diameter f SLY, Rpm % pm Limonene 350 57 75i12 Rosemary oil 350 68 728 500 58 43*13 750 67 42i5.6 1000 50 201t5.1 Without 350 75 7W15 aeachvalue represents the mean f standard deviation (SD) of fifty measurements Good results in terms of recovery, shape, size distribution were obtained in the case of blank microcapsules (Table 1). The presence of oil causes deficiencies of the microcapsule recovery. In order to facilitate the encapsulation of oil, this should have a density comparable to that of the aqueous external phase and complete immiscibility with the external phase [6,9]. This could explain the increased yield microencapsulation of Rosemary oil (density 0.91 g / d ) compared to limonene (density 0.84 gd).

Determination of limonene content in ethyl cellulose microcapsules The limonene content was estimated by FT-Raman spectroscopy. FT-Raman spectra of limonene and cyclohexane are presented in Fig. 2. The FT-Raman spectrum of R(+,)limonene showed characteristic peaks at 1678 cm-' ( v of ~cyclohexene)and 1645 cm- ( V C ~of vinyl) [10,11]. In FT-IR Raman spectrum of cyclohexane there is no absorption in 1600-1700 cm" region. Thus, the limonene amount from cyclohexane solutions can be determined by monitoring the intensities of the 1678 or 1645 cm-' peaks. For calibration, FT-Raman spectra of different concentrations of limonene in cyclohexane were recorded (see Fig.3). In our study, the intensity of 1645 cm-' was correlated to limonene content in cyclohexane. There was a linear relationship. The calibration curve had the following equation y = 12.2577x+0.00955,R=0.98 (Fig. 4). Content (%) of R(+)limonene in EC microcapsules was measured using the above equation. According to the proposed method, the EC microcapsules contained 9.8*5.5% limonene.


Raman shift cm-' Fig. 2 FT-Raman spectra of R(+)limonene and cyclohexane

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Cotton fabrics were treated with BTCA, EC microcapsules and catalyst. After the unreacted BTCA and catalyst were washed, the carbonyls retained in the fabrics existed in three forms - ester, carboxylic acid, and carboxylate anion [13,14]. In Fig. 6 the bands due to an ester carbonyl appear around 1717-1730 cm-'. However, a band in this area is ambiguous and can be interpreted either as an ester carbonyl band or a carboxyl carbonyl band [13, 141. The post treatment of finished fabrics in an alkaline solution converts the acid to carboxylate anion, which absorbs at 1570 cm-', while the ester carbonyl is left unchanged. In FT-IR spectra of alkaline post treated finished fabrics, the band intensity near 1700 cm-' decreased while the intensity of the carboxylate region centered at 1570 cm-' increased [15-161. From FT-IR spectra we have got the evidence that some crosslinking between hydroxyl grou s of EC microcapsules via ester bonds occurs as well. The presence of 1717-1722 cm-Pabsorption indicates that there are ester links between BTCA and hydroxyl groups of cellulose, hydroxyl groups of EC microcapsules, or both. The large absorption centered at 1700 cm-' is due to the carboxylic acid of unreacted BTCA. The overlapped bands at 1700 and 1690 cm-' are due to the hydrogen bonded and flee carboxylic groups of BTCA [141. The absorption band at 1737-1744 cm-' could be ascribed to the carbonyl vibration of camphor or bornyl acetate from microencapsulated Rosemary oil. From Fig. 6 it is possible to see that the intensity of this band increases when textile material encapsulated with Rosemary oil is heated on 150 "C (spectrum c). We can conclude that temperature of 150 "C is too high for the treatment of EC microcapsules and some of the oil penetratedevaporatesthrough the microcapsules wall. The curring temperature was reduced to 110 "C; spectrum a in Fig 6 indicates that some esterification occurs during the thennofixation; the intensity of 1743 cm'' band is low which indicates that there was no oil penetration through the microcapsules wall, so the thermofixation temperature of 0 Woodhead Publishing Limited, 201 0 231

110 "C is high enough for grafting of EC microcapsules onto hydroxyl groups of cellulose using BTCA.

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cotton and keep their shape. The EC microcapsules are stable after cold water washing, as the microphotography revealed.

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