Nagendra Kumar Kaushik ^a,*, Pradeep Bhartiya ^a, Neha Kaushik ^b, Yungoh Shin ^a, Linh Nhat Nguyen ^a, Jang Sick Park ^a, Doyoung Kim ^a, Eun Ha Choi ^a,*

^a Department of Electrical and Biological Physics, Plasma Bioscience Research Center, Kwangwoon University, Seoul, 01897, Republic of Korea ^b Department of Biotechnology, College of Engineering, The University of Suwon, Hwaseong-si, 18323, Republic of Korea

^* Corresponding author.

The ongoing pandemic caused by the novel coronavirus, SARS-CoV-2, is influencing global health. Moreover, there is a major threat of future coronaviruses affecting the entire world in a similar, or even more dreadful, manner. Therefore, effective and biocompatible therapeutic options against coronaviruses are urgently needed. To address this challenge, medical specialists require a well-informed and safe approach to treating human coronaviruses (HCoVs). Herein, an environmental friendly approach for viral inactivation, based on plasma technology, was considered. A microwave plasma system was employed for the generation of the high amount of gaseous nitric oxide to prepare nitric oxide enriched plasma-activated water (NO-PAW), the effects of which on coronaviruses, have not been reported to date. To determine these effects, alpha-HCoV-229E was used in an experimental model. We found that NO-PAW treatment effectively inhibited coronavirus infection in host lung cells, visualized by evaluating the cytopathic effect and expression level of spike proteins. Interestingly, NO-PAW showed minimal toxicity towards lung host cells, suggesting its potential for therapeutic application. Moreover, this new approach resulted in viral inactivation and greatly improved the gene levels involved in host antiviral responses. Together, our findings provide evidence of an initiation point for further progress toward the clinical development of antiviral treatments, including such coronaviruses.