Human coronavirus inactivation by atmospheric pressure helium plasma

The recent global pandemic of Corona Virus Disease-19 has impacted all aspects of society, producing a growing demand for a powerful virus inactivation method. To assess a potential and mechanism of human coronavirus inactivation using atmospheric pressure plasma (APP) technology, replication of a human coronavirus (HCoV-229E) after He + H2O APP plume exposure was evaluated using rhesus monkey kidney epithelial cells. The HCoV-229E titers were reduced by 3 log(10)TCID(50) after the APP exposure for 30 s, showing a strong virus-inactivation efficacy of the APP. It was experimentally verified that the APP produced the liquid-phase reactive oxygen and nitrogen species (RONS) at high rates [e.g. (OH)-O-center dot: similar to 1.7 nmol s(-1), H2O2 (including H2O2 precursors): similar to 9.2 nmol s(-1), NO2 (-) (including NO2 (-) precursors): similar to 3.3 nmol s(-1)]. However, an administration of H2O2 with NO2 (-) failed to inactivate the virus and only Mn type superoxide dismutase among several RONS scavengers for (OH)-O-center dot, HO2 (center dot)/O-2 O-center dot-, 1(2), and (NO)-N-center dot/(NO2)-N-center dot was significantly effective for the recovery of the APP-induced decrease in the viral titers. This suggests O-2 (center dot-)-related chemical reaction in a network of interconnected reactions induced by the APP exposure is very important for the APP-induced virus inactivation. These results provide new insight into a more efficient inactivation method of human coronavirus using APPs.