Evaluation Of The Effectiveness And Mechanism Of Plasma Killing Of Coronaviruses

SARS-CoV-2 virus is a novel coronavirus that has caused the global pandemic COVID-19 outbreak.The virus is mainly spread by droplet transmission,is fast in the population and has the potential to cause serious health problems,including respiratory illness and damage to multiple organ systems.Plasma is an emerging antivirus technology that has attracted much attention for its efficiency,greenness and broad spectrum.Based on this technology,this paper independently builds a low-temperature plasma device with different electrode structures and investigates the inactivation effect of the device on typical coronaviruses,and investigates the inactivation mechanism of coronaviruses under the action of plasma in combination with experiments and simulations.The main studies and results are as follows:（1）Plasma degradation of surface coronaviruses was studied.In this study,AC and pulsed power supplies were used to excite plasma jets to perform inactivation experiments on coronaviruses,and the discharge characteristics,optical properties,the content of active particles produced and the killing efficiency of coronaviruses by the two plasmas were compared and analysed.The results showed that the AC plasma released more active material and had a higher temperature,and was therefore slightly more effective in degrading coronaviruses than the pulsed plasma jet.However,the discharge characteristics of pulsed plasma are gentler and do not harm the surface of the object.Furthermore,pulsed plasma can completely inactivate the new coronavirus-like GX＿P2V,SARS-CoV-2 pseudotypes,porcine coronavirus PEDV and SADS-CoV in a short period of time,showing a broad spectrum of coronavirus inactivation.Further studies have shown that plasma-generated short-lived active species play an important role in the virus inactivation process,leading to morphological changes and loss of infectivity of the virus.The order of influence of these short-lived species is:ONOO^->O₂^->¹O₂>-OH.（2）Study of the degradation of coronaviruses in wastewater by a liquid-phase corona plasma discharge device.A liquid phase corona plasma discharge device was used to treat coronaviruses in large volumes of wastewater.The study showed that different discharge spacing affects the discharge current,discharge power and active material yield of the plasma.Increasing the discharge spacing results in a more stable and large discharge area,but reduces the discharge power and decreases the amount of active material produced,which is detrimental to the inactivation of viruses in water.By building a two-dimensional axisymmetric model,it was found that the difference in electron density and electric field strength of the plasma at different discharge spacing conditions was responsible for the difference in power and active substance yield.Further studies have shown that the technique can effectively kill a large number of virus-like particles in water,including transcription-and replication-competent SARS-CoV-2 virus,coronavirus GX＿P2V,pseudotyped SARS-CoV-2 variants and porcine epidemic diarrhoea virus,in a short period of time with an inhibition rate of over 99%.It was also shown that plasma-generated active species,such as ONOO^-and O₃,play a disruptive role in the replication and assembly process of coronaviruses,which is essential for virus inactivation,and in addition,plasma treatment does not adversely affect the survival of human cell lines.This method provides an efficient and environmentally friendly strategy to eliminate SARS-CoV-2 and other coronaviruses from wastewater.