Sterilisation of biomaterials and medical devices © Woodhead Publishing Limited, 2012 Related titles: Surface modifi cation of biomaterials: methods analysis and applications (ISBN 978-1-84569-640-5) Surface modifi cation of biomaterials plays a signifi cant role in determining the outcome of biological-material interactions. With the appropriate modifi cation, a material’s surface can be tailored to improve biocompatibility, adhesion and cell interactions. Consequently, surface modifi cation is vital in the development and design of new biomaterials and medical devices. Surface modifi cation of biomateri- als provides readers with a comprehensive guide to the most pertinent surface modi- fi cation techniques and technologies. Part I covers chemical surface modifi cation methods, while Part II discusses topography and analysis methods. The fi nal section of the book examines applications of this important technology. Coatings for biomedical applications (ISBN 978-1-84569-568-2) The biomaterials sector is rapidly expanding due to the increase in healthcare spending worldwide. Coatings and surface modifi cation of biomaterials provides a means to improve the wear of joints, change the biological interaction between implant and host and combine the properties of various materials to improve device performance. The considerable interest in coatings for biomedical applications has resulted in a great deal of research in industry and academia. This book provides a comprehensive review of coatings and surface modifi cation for biomedical applica- tions, including background, theory, materials and applications. The clear structure and concise review of research provides a valuable resource to researchers in the fi eld of biomedical coatings. Cellular response to biomaterials (ISBN 978-1-84569-358-9) The response of cells to biomaterials is critical in medical devices. Specifi c cell responses may be benefi cial – encouraging adhesion, healing or cell multiplication. Cellular response to biomaterials examines the response of cells with a wide range of materials, targeted at specifi c medical applications. Chapters in the fi rst section review cellular response to polymers and ceramics. A second group of chapters dis- cuss cell responses and regenerative medicine for nerves, muscles and orthopaedic materials. The fi nal set of chapters analyse the effect of surface chemistry and how it can be manipulated to provoke a useful cell response. Details of these books and a complete list of titles from Woodhead Publishing can be obtained by: • visiting our web site at www.woodheadpublishing.com • contacting Customer Services (e-mail: [email protected]; fax: +44 (0) 1223 832819; tel.: +44 (0) 1223 499140 ext. 130; address: Woodhead Publishing Limited, 80, High Street, Sawston, Cambridge CB22 3HJ, UK) • in North America, contacting our US offi ce (e-mail: usmarketing@woodhead- publishing.com; tel.: (215) 928 9112; address: Woodhead Publishing, 1518 Walnut Street, Suite 1100, Philadelphia, PA 19102–3406, USA If you would like e-versions of our content, please visit our online platform: www. woodheadpublishingonline.com. Please recommend it to your librarian so that everyone in your institution can benefi t from the wealth of content on the site. © Woodhead Publishing Limited, 2012 Woodhead Publishing Series in Biomaterials: Number 46 Sterilisation of biomaterials and medical devices Edited by Sophie Lerouge and Anne Simmons Oxford Cambridge Philadelphia New Delhi © Woodhead Publishing Limited, 2012 Published by Woodhead Publishing Limited, 80 High Street, Sawston, Cambridge CB22 3HJ, UK www.woodheadpublishing.com www.woodheadpublishingonline.com Woodhead Publishing, 1518 Walnut Street, Suite 1100, Philadelphia, PA 19102-3406, USA Woodhead Publishing India Private Limited, G-2, Vardaan House, 7/28 Ansari Road, Daryaganj, New Delhi – 110002, India www.woodheadpublishingindia.com First published 2012, Woodhead Publishing Limited © Woodhead Publishing Limited, 2012. Note: the publisher has made every effort to ensure that permission for copyright materials has been obtained by authors wishing to use such material. The authors and the publisher will be glad to hear from any copyright holder it has been possible to contact. The authors have asserted their moral rights. This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. Reasonable efforts have been made to publish reliable data and information, but the authors and the publisher cannot assume responsibility for the validity of all materials. Neither the authors nor the publisher, nor anyone else associated with this publication, shall be liable for any loss, damage or liability directly or indirectly caused or alleged to be caused by this book. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfi lming and record- ing, or by any information storage or retrieval system, without permission in writing from Woodhead Publishing Limited. The consent of Woodhead Publishing Limited does not extend to copying for general distribution, for promotion, for creating new works, or for resale. Specifi c permission must be obtained in writing from Woodhead Publishing Limited for such copying. Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identifi cation and explanation, without intent to infringe. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. Library of Congress Control Number: 2012945021 ISBN 978-1-84569-932-1 (print) ISBN 978-0-85709-626-5 (online) ISSN 2049-9485 Woodhead Publishing Series in Biomaterials (print) ISSN 2049-9493 Woodhead Publishing Series in Biomaterials (online) The publisher’s policy is to use permanent paper from mills that operate a sustainable forestry policy, and which has been manufactured from pulp, which is processed using acid-free and elemental chlorine-free practices. Furthermore, the publisher ensures that the text paper and cover board used have met acceptable environmental accreditation standards. Typeset by Newgen Knowledge Works Pvt Ltd, India Printed by TJ International, Padstow, Cornwall, UK © Woodhead Publishing Limited, 2012 Contents Contributor contact details xi Woodhead Publishing Series in Biomaterials xiii 1 Introduction to sterilization: defi nitions and challenges 1 S. LEROUGE, École de technologie supérieure, Canada 1.1 Introduction 1 1.2 Defi nitions of sterilization in the context of biomaterials 2 1.3 Validation, monitoring and safety of sterilization methods 5 1.4 Challenges and constraints of sterilization methods 9 1.5 Ideal versus actual sterilization methods 13 1.6 Conclusions 14 1.7 References 17 2 Steam and dry heat sterilization of biomaterials and medical devices 20 W. J. ROGERS, Independent Healthcare Consultant, USA 2.1 Introduction 20 2.2 Steam sterilization 21 2.3 Different methods of steam sterilization 27 2.4 Test methods for the effectiveness of steam sterilization 33 2.5 Dry heat sterilization 41 2.6 Testing and validating dry heat sterilization 48 2.7 Conclusions 50 2.8 Sources of further information 52 2.9 References 53 v © Woodhead Publishing Limited, 2012 vi Contents 3 Sterilisation of healthcare products by ionising radiation: principles and standards 56 B. J. PARSONS, Leeds Metropolitan University, UK 3.1 Introduction 56 3.2 Interaction of ionising radiation with matter 57 3.3 Sources of ionising radiation 61 3.4 Validation and international standards of sterilisation by ionising radiation 63 3.5 Conclusions and future trends 69 3.6 Sources of further information and advice 69 3.7 References 69 4 Ethylene oxide (EO) sterilization of healthcare products 71 G. C. MENDES, T. R. S. BRANDÃO and C. L. M. SILVA, Universidade Católica Portuguesa, Portugal 4.1 Introduction 71 4.2 Advantages of ethylene oxide (EO) sterilization 72 4.3 Disadvantages of ethylene oxide (EO) sterilization 73 4.4 Sterilization process characterization 79 4.5 Process defi nition 84 4.6 Process optimization and the process challenge device 88 4.7 Qualifi cation of ethylene oxide (EO) sterilization 90 4.8 Contract sterilization 93 4.9 Acknowledgments 93 4.10 References 93 5 Non-traditional sterilization techniques for biomaterials and medical devices 97 S. LEROUGE, École de technologie supérieure, Canada 5.1 Introduction 97 5.2 Non-traditional sterilization methods 99 5.3 Novel non-traditional sterilization methods 110 5.4 Conclusions 113 5.5 References 113 6 Sterilization and decontamination of surfaces by plasma discharges 117 F. ROSSI, European Commission – Joint Research Centre, Italy and O. KYLIÁN, Charles University, Czech Republic 6.1 Introduction 117 6.2 Overview of plasma generation 119 © Woodhead Publishing Limited, 2012 Contents vii 6.3 Plasma generation at low and atmospheric pressures 121 6.4 Interaction of plasma with biological pathogens: bacteria and bacterial spores 129 6.5 Interaction of plasma with biological pathogens: pyrogens and proteins 134 6.6 Further issues with the use of plasma for sterilization purposes 141 6.7 Conclusions and future trends 144 6.8 References 145 7 Sterilisation techniques for polymers 151 W. J. ROGERS, Independent Healthcare Consultant, USA 7.1 Introduction 151 7.2 Dry-heat sterilisation 152 7.3 Steam (moist heat) sterilisation 163 7.4 Ethylene oxide (EO) sterilisation 168 7.5 Low-temperature hydrogen peroxide with plasma 173 7.6 Ozone sterilisation 175 7.7 Radiation sterilisation 179 7.8 Sterilisation and polymer effi ciency 186 7.9 Comparative effi ciencies of sterilisation techniques for different polymers 188 7.10 Post-implantation effects 192 7.11 Dry heat sterilisation of silicones 194 7.12 Ethylene oxide (EO) sterilisation of polymers 196 7.13 Sterilisation issues relating to biodegradable polymers and coatings 200 7.14 Biocompatibility testing 202 7.15 Conclusions 206 7.16 Sources of further information 209 7.17 References 210 8 Sterilisation of healthcare products by ionising radiation: sterilisation of drug-device products and tissue allografts 212 B. J. PARSONS, Leeds Metropolitan University, UK 8.1 Introduction 212 8.2 The effect of radiation on aqueous systems 215 8.3 Sterilisation of aqueous solutions of proteins and enzymes: reactions of free radicals with proteins 217 © Woodhead Publishing Limited, 2012 viii Contents 8.4 The sterilisation of proteins in aqueous solution 220 8.5 Sterilisation of drugs using radiation 224 8.6 Sterilisation of drug-delivery systems using radiation 227 8.7 Sterilisation of tissue allografts using radiation 230 8.8 Conclusions and future trends 232 8.9 Sources of further information and advice 233 8.10 References 234 9 Antimicrobial coatings for ‘self-sterilisation’ 240 C. W. DUNNILL and I. P. PARKIN, University College London, UK 9.1 Introduction 240 9.2 Self-sterilising surfaces 243 9.3 Antimicrobial metal surfaces 246 9.4 Light-activated antimicrobial surfaces 247 9.5 Conclusions 255 9.6 Future trends 257 9.7 Sources of further information 257 9.8 References 257 10 Prions and endotoxins: reprocessing strategies for reusable medical devices 261 L. M. SEHULSTER, Centers for Disease Control and Prevention, USA 10.1 Introduction: prion disease epidemiology 261 10.2 Prion resistance to inactivation: early research 263 10.3 Current recommendations for instrument reprocessing 267 10.4 Factors that impact the decision to use prion-inactivating methods 273 10.5 Important issues associated with cleaning/decontamination 279 10.6 Research developments towards a validated reprocessing strategy 289 10.7 Bacterial endotoxins 293 10.8 Device reprocessing strategies for endotoxin 295 10.9 References 299 11 Future trends for the sterilisation of biomaterials and medical devices 310 A. SIMMONS, University of New South Wales, Australia 11.1 Introduction 310 11.2 Common sterilisation techniques 311 © Woodhead Publishing Limited, 2012 Contents ix 11.3 Future trends 314 11.4 Conclusions 317 11.5 References 318 Index 321 © Woodhead Publishing Limited, 2012