Inactivation of bacterial spores and viruses in biological material using supercritical carbon dioxide with sterilant

Abstract The purpose of this study was to validate supercritical carbon dioxide (SC‐CO₂) as a terminal sterilization method for biological materials, specifically acellular dermal matrix. In this study, bacterial spores, Bacillus atrophaeus, were inoculated onto porcine acellular dermal matrix to serve as a “worst case” challenge device. The inactivation of the spores by SC‐CO₂ with peracetic acid (PAA) sterilant was analyzed as a function of exposure times ranging from 1 to 30 min. A linear inactivation profile for the Bacillus atrophaeus spores was observed, and a SC‐CO₂ exposure time of 27 min was determined to achieve a sterility assurance level of 10⁻⁶. The inactivation of viruses was also studied using Encephalomyocarditis (EMC) viruses. After 15 min of exposure to SC‐CO₂ with PAA sterilant, more than a 6 log₁₀ reduction was observed for EMC viruses. Biochemical and biomechanical evaluations showed that the SC‐CO₂ treatment with PAA sterilant did not cause significant changes in porcine acellular matrix's susceptibility to collagenase digestion, tensile or tear strength, indicating limited alteration of the tissue structure following SC‐CO₂ sterilization. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009