A sterilization system using ultraviolet photochemical reactions based on nitrous oxide and oxygen gases

• Sterilization of G. stearothermophilus spores using active oxygen with N2O was investigated.
• The active oxygen using nitrous oxide generates nitrogen dioxide, which affects the effective sterilization.
• Successful sterilization was achieved in active oxygen using N2O in lumen devices.

Active oxygen species (AOS) generated under ultraviolet (UV) lamps can be applied for various industrial processes owing to extremely strong oxidative abilities. We have already reported on an application of the AOS for a sterilization process of microorganisms.Here, a sterilization method using active oxygen generated under ultraviolet (UV) lamps introducing nitrous oxide (N2O) and oxygen gases into a vacuum chamber was investigated. Nitrogen dioxide (NO2) gas was readily produced from N2O by UV photochemical reactions under the low-pressure mercury lamp and then used to sterilize medical devices. We compared the ability of the N2O gas to sterilize Geobacillus stearothermophilus spores with those of conventional methods. Successful sterilization of spores on various biological indicators was achieved within 60 min, not only in sterilization bags but also in a lumen device.