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

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