Selective plasma synthesis of dinitrogen pentoxide and ozone for sterilization and virus inactivation*

The dinitrogen pentoxide (N₂O₅) is attractive for wide range of academic fields, but has not yet been used in the bio-medical fields, because multiple hazardous raw materials are necessary to synthesize N₂O₅ in the conventional method. Recently, we have developed a new air atmospheric pressure plasma device, enabling selective production of N₂O₅ exclusively from sources of air and electricity. This device can also provide the NO_x- or ozone-rich gas simply with electric switching for the high- and low-temperature plasma reactors. Using this device, we investigated effects on C. gloeosporioides (strawberry pathogen) sterilization and Qβ phage (RNA virus) inactivation. C. gloeosporioides germination rate was measured as an index of sterilization effect, and it was found that the N₂O₅ exposure for 60 s significantly decreased the germination rate. Furthermore, mist particles containing Qβ phage were exposed to N₂O₅, and it was confirmed that the Qβ phage was completely inactivated by N₂O₅. Because N₂O₅ in contact with water is well known to generate a reactive intermediate such as nitronium ion, nitronium ion might be a key factor in N₂O₅ induced virus inactivation. In the presentation, differences in the effects of N₂O₅ and ozone on virus inactivation will be discussed.