Performance evaluation of bactericidal effect and endotoxin inactivation by low‐temperature ozone/hydrogen peroxide mixed gas exposure

• Published in: Journal of biomedical materials research. Part B, Applied biomaterials Applied biomaterials, 2021-11, Vol.109 (11), p.1807-1816
• Main Authors: Nomura, Yusuke, Yamamura, Junji, Fukui, Chie, Fujimaki, Hideo, Sakamoto, Kazuyuki, Matsuo, Ken‐ichi, Kuromatsu, Hisashi, Kikuchi, Yutaka, Haishima, Yuji
• Format: Article
• Language: English
• Subjects: Autoclaving; Biocompatibility; Biomaterials; Biomedical materials; Cerebrospinal fluid; Coagulation; Cutting tools; Cytotoxicity; Deactivation; Disinfection; E coli; endotoxin inactivation; Endotoxins; Endotoxins - chemistry; Escherichia coli - chemistry; Ethylene oxide; Ethylene Oxide - chemistry; Exposure; gas sterilization; Geobacillus stearothermophilus - chemistry; Humans; Hydrogen peroxide; Hydrogen Peroxide - chemistry; Inactivation; Low temperature; Materials research; Materials science; Medical equipment; Microorganisms; ozone; Performance evaluation; Polymers; Pyrogen; Regenerative medicine; reusable medical device; Sterility; Sterilization; Toxicity; Utensils
• ISSN: 1552-4973; 1552-4981
• DOI: 10.1002/jbm.b.34840

This study evaluated the performance of a new O3/H2O2 mixed gas sterilization instrument for killing microorganisms and inactivating bacterial endotoxin at low temperatures. Sterility assurance level was achieved by an over 6‐log reduction of Geobacillus stearothermophilus ATCC 12980, and the decimal reduction value was 0.77 min in sterilization mode. A reduction of over 3 logs in Limulus amebocyte lysate coagulation activity of purified endotoxin from Escherichia coli was observed after treatment in endotoxin‐inactivation mode. The same inactivation ability was observed when treating dried bacterial cells. Biomaterials made of polymer or metal did not exhibit cytotoxicity after gas exposure at O3 concentrations below 200 ppm. As the results of human cell‐based pyrogen testing, significant amounts of endotoxin that were over the limit for medical devices contacting cerebrospinal fluid (2.15 EU/device) were detected on scissors washed with a washer‐disinfector and sterilized with ethylene oxide or autoclaving. In contrast, endotoxin decreased to 0.29 ± 0.05 EU/device after O3/H2O2 mixed gas sterilization in endotoxin‐inactivation mode. Compared to conventional gas sterilization methods, O3/H2O2 mixed gas has high sterilization ability and a strong capacity to inactivate endotoxin. It is expected that this sterilization technology will improve the safety of reusable medical devices and utensils for regenerative medicine.