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

Area of Science:

• Microbiology
• Biotechnology
• Materials Science

Background:

• Sterilization is crucial for medical devices, especially those used in regenerative medicine.
• Conventional methods like ethylene oxide and autoclaving may not fully inactivate bacterial endotoxins.
• Low-temperature sterilization is needed for heat-sensitive biomaterials.

Purpose of the Study:

• To evaluate a novel ozone (O3) / hydrogen peroxide (H2O2) mixed gas sterilization instrument.
• To assess its efficacy in killing microorganisms and inactivating bacterial endotoxins at low temperatures.
• To compare its performance against conventional sterilization methods.

Main Methods:

• Sterilization efficacy was tested against Geobacillus stearothermophilus ATCC 12980.
• Bacterial endotoxin inactivation was measured using Limulus amebocyte lysate assay.
• Cytotoxicity of treated biomaterials (polymer, metal) was assessed.
• Human cell-based pyrogen testing was performed on sterilized medical devices (scissors).

Main Results:

• Achieved over a 6-log reduction of Geobacillus stearothermophilus, meeting sterility assurance levels.
• Demonstrated over a 3-log reduction in endotoxin activity and inactivated dried bacterial cells.
• O3/H2O2 gas exposure below 200 ppm showed no cytotoxicity for biomaterials.
• Reduced endotoxin levels on scissors to 0.29 ± 0.05 EU/device, significantly lower than conventional methods.

Conclusions:

• Ozone/hydrogen peroxide mixed gas sterilization is highly effective against microorganisms and endotoxins at low temperatures.
• This method is safe for common biomaterials and superior to ethylene oxide and autoclaving in endotoxin inactivation.
• The technology promises enhanced safety for reusable medical devices and regenerative medicine applications.