Effect of Plasma-Activated Medium and Water on Replication and Extracellular Virions of Herpes Simplex Virus-1

АBSTRACT: We use a surface-wave sustained discharge (SWD) in argon at atmospheric pressure (using a plasma torch) in these experiments. The plasma torch is sustained using a 2.45-GHz electromagnetic wave with applied microwave powers of 13, 15, and 20 W. At these discharge conditions, the length of the plasma torch outside of the quartz tube is ~1–1.5 cm, and the gas plasma temperature does not exceed 40°C. This allows direct treatment of samples using the active zone of the discharge. In the cytotoxicity study, only two of the experimental settings achieve up to 50% survival of the cell monolayer after adding plasma-treated medium. Examining the effect of the plasma torch treatment media on herpes simplex virus-1 replication, we found that none of the applied experimental assays show significant protection on the cell monolayer. In a study of the virucidal action of a plasma-treated viral suspension diluted with sterile water at a ratio of 1:2 that was treated for 300 s at 13-W wave power, a decrease in the viral sample titer occurred unlike in the 1.67 log10 control. Using optical emission spectroscopy, we found that OH intensity increases at the contact point between plasma and the water surface. Intensity of NO-γ also increases to the contact point with applied power. We also monitored the amount of peroxide radicals in plasma-treated water and nutrient medium in the presence of lucigenin.