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(m)ay contribute to the inactivation of influenza viruses by N-2 gas plasma.