N(2) Gas Plasma Inactivates Influenza Virus by Inducing Changes in Viral Surface Morphology, Protein, and Genomic RNA

We have recently treated with N(2) gas plasma and achieved inactivation of bacteria. However, the effect of N(2) gas plasma on viruses remains unclear. With the aim of developing this technique, we analyzed the virucidal effect of N(2) gas plasma on influenza virus and its influence on the viral components. We treated influenza virus particles with inert N(2) gas plasma (1.5 kpps; kilo pulses per second) produced by a short high-voltage pulse generated from a static induction thyristor power supply. A bioassay using chicken embryonated eggs demonstrated that N(2) gas plasma inactivated influenza virus in allantoic fluid within 5 min. Immunochromatography, enzyme-linked immunosorbent assay, and Coomassie brilliant blue staining showed that N(2) gas plasma treatment of influenza A and B viruses in nasal aspirates and allantoic fluids as well as purified influenza A and B viruses induced degradation of viral proteins including nucleoprotein. Analysis using the polymerase chain reaction suggested that N(2) gas plasma treatment induced changes in the viral RNA genome. Scanning electron microscopy analysis showed that aggregation and fusion of influenza viruses were induced by N(2) gas plasma treatment. We believe these biochemical changes may contribute to the inactivation of influenza viruses by N(2) gas plasma.