title: Slow chlorine releasing compounds: A viable sterilisation method for bioabsorbable nanocomposite biomaterials.
abstract: OBJECTIVE
  Selection of the appropriate sterilisation method for biodegradable materials has been a challenging task. Many conventional sterilisation methods are not suitable for the next generation of biomaterials, mainly due to their complex composition, based on nanomaterials, often incorporating bioactive moieties. In this study, we investigate sterilisation efficacy of slow chlorine releasing compound sodium dichloroisocyanurate dihydrate (SDIC) for polyhedral oligomeric silsesquioxane (POSS)-poly(caprolactone urea-urethane) (PCL) scaffolds in comparison with conventional sterilisation methods.
  
  
  METHODS
  POSS-PCL scaffolds were subjected to 70% ethanol, UV, and SDIC sterilisation methods. Samples were immersed in tryptone soya broth (TSB) and thioglycollate medium (THY) and after seven days visually inspected for signs of microbial growth. Bulk and surface properties and molecular weight distribution profiles of the scaffolds after sterilization were investigated using FTIR analysis, surface hydrophilicity, scanning electron microscopy analysis, tensile strength testing, and gel-permeation chromatography (GPC). Adipose-derived stem cells (ADSC) were seeded on the scaffolds and AlamarBlue® viability assay was performed to investigate cell metabolic activity. Confocal imaging of rhodamine phalloidin and Dapi stained ADSC on scaffolds was used to demonstrate cell morphology.
  
  
  RESULTS
  GPC results showed that autoclaving led to a significant decrease in the molecular weight of POSS-PCL, whereas ethanol caused visible deformation of the polymer 3D structure and UV radiation did not effectively sterilise the scaffolds. AlamarBlue® analysis showed metabolic activity close to that of tissue culture plastic for ethanol and SDIC.
  
  
  CONCLUSIONS
  SDIC sterilisation can be safely applied to biodegradable scaffolds unsuitable for the more common sterilisation methods.
authors.affiliation: Reconstructive Surgery & Regenerative Medicine Group, Institute of Life Sciences (ILS), Swansea University Medical School, Swansea, UK Welsh Centre for Burns & Plastic Surgery, ABMU Health Board, Swansea, UK UCL Centre for Nanotechnology & Regenerative Medicine, University College London, Royal Free London NHS Foundation Trust, London, UK naghmeh62@yahoo.com.
authors.forename: Naghmeh
authors.initials: N
authors.lastname: Naderi
authors.affiliation: UCL Centre for Nanotechnology & Regenerative Medicine, University College London, Royal Free London NHS Foundation Trust, London, UK.
authors.forename: Michelle
authors.initials: M
authors.lastname: Griffin
authors.affiliation: Polymer Chemistry Laboratory, School of Engineering and Materials Science, Queen Mary, University of London, London, UK.
authors.forename: Edward
authors.initials: E
authors.lastname: Malins
authors.affiliation: Polymer Chemistry Laboratory, School of Engineering and Materials Science, Queen Mary, University of London, London, UK.
authors.forename: Remzi
authors.initials: R
authors.lastname: Becer
authors.affiliation: Department of Plastic Surgery, Royal Free London NHS Foundation Trust, London, UK.
authors.forename: Afshin
authors.initials: A
authors.lastname: Mosahebi
authors.affiliation: Reconstructive Surgery & Regenerative Medicine Group, Institute of Life Sciences (ILS), Swansea University Medical School, Swansea, UK Welsh Centre for Burns & Plastic Surgery, ABMU Health Board, Swansea, UK.
authors.forename: Iain S
authors.initials: IS
authors.lastname: Whitaker
authors.affiliation: UCL Centre for Nanotechnology & Regenerative Medicine, University College London, Royal Free London NHS Foundation Trust, London, UK.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Seifalian
mesh_terms: D020341:Absorbable Implants; D017667:Adipocytes / Q000166:cytology; D000273:Adipose Tissue / Q000166:cytology; D001672:Biocompatible Materials / Q000737:chemistry*; D018929:Cell Culture Techniques; D002713:Chlorine / Q000737:chemistry*; D002845:Chromatography; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D053761:Nanocomposites / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D016062:Porosity; D017550:Spectroscopy, Fourier Transform Infrared; D013234:Stem Cells / Q000166:cytology; D013242:Sterilization; D013718:Tensile Strength; D013997:Time Factors; D054457:Tissue Scaffolds / Q000737:chemistry; D014227:Triazines / Q000737:chemistry; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D014227:Triazines; D014867:Water; C016240:polycaprolactone; D002713:Chlorine; C011765:troclosene
keywords: ADSC; GPC; SEM; Sterilisation; bleach; nanocomposite; polymer