| Mechanisms of Supercritical Carbon Dioxide Sterilization of Bacterial Spores | ||
| Jian Zhang1, Michael A. Matthews2, Nishita Dalal3, Clint Saunders4, Lashanda Waller5, Alvin Fox5, Karen Fox5, Michael Drews6, Martine LaBerge7 and Yuehuei An8, (1)University of South Carolina, Dept. of Chemical Engineering, Columbia, SC 29208, (2)University of South Carolina, Department of Chemical Engineering, Columbia, SC 29208, (3)University of South Carolina, 301 Main st., Room 2C02, Columbia, SC 29208, (4)Department of Pathology and Microbiology, University of South Carolina, Columbia, SC 29208, (5)University of South Carolina, USC, Department of Pathology and Microbiology, Columbia, SC 29208, (6)School of Materials Science and Engineering, Clemson University, Clemson, SC 29634, (7)Department of Bioengineering, Clemson University, Clemson, SC 29634, (8)Orthopaedic Research Laboratories, Medical University of South Carolina, Charleston, SC 29403 Sterilization of implants and medical devices (such as endoscopes) is essential to prevent clinical infection. Commercial sterilization using the steam autoclave, ethylene oxide, or irradiation has serious limitations when sterilizing heat-sensitive polymers or substrates with complex internal structures. To meet the clinical needs associated with these situations we evaluated the viability of using SCCO2 as a sterilant. Experimental results verified that with approximately 200 ppm of H2O2 (equivalent to 5 microliters of 30% H2O2), SCCO2 has successfully sterilized all three commercial sterilization indicators. However, the addition of 1 mL of de-ionized water was not as effective as 5 microliters of H2O2. The TEM images of SCCO2/H2O2 treated B. atrophaeus spores revealed visible damage of spore exosporium and spore coat. BacLight fluorescence assay showed higher degree of penetration of fluorescent dyes with SCCO2/H2O2 treated spores, comparing with the staining pattern of untreated spores. The deeper penetration of fluorescent dyes indicates compromised spore permeability barrier. DPA analysis showed higher amount of DPA leakage after SCCO2/H2O2 treatment compared to the trace amount of DPA release from untreated and pure SCCO2 treatment. This was an indication of perforation of the spore coat. Based on these studies, we infer that disruption and perforation of the outer layers of spore structures are the cause of spore deactivation. Extended Abstract Status: Not Uploaded | ||