Slow chlorine releasing compounds: A viable sterilisation method for bioabsorbable nanocomposite biomaterials.

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. CONCLUSION SDIC sterilisation can be safely applied to biodegradable scaffolds unsuitable for the more common sterilisation methods.