evere acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the etiological agent of coronavirus disease 2019 (COVID-19) is transmitted person-to-person via respiratory droplets and through smaller droplets that are light enough to form an aerosol that remain suspended in the air and contaminate the surfaces particularly in indoor conditions. Thus, effective measures are needed to prevent SARS-CoV-2 transmission in indoor environments. In this regard, we have investigated the ability of a system based on combining tungsten trioxide-based (WO3) photocatalyst and copper nanoclusters coated fabric to inactivate SARS-CoV-2. To this purpose, an infectious SARS-CoV-2 suspension was introduced in a photocatalytic reactor containing a WO3 coated grid and a lighting system that activates WO3. Aliquots of fluid were collected every 10 min (up to 60 min) and tested for their infectivity by means of a viral plaque assay in Vero cells whereas, in parallel, the viral RNA content was measured by quantitative PCR (qPCR). A 1:3,400 ratio of plaque forming units (PFU) vs. viral RNA copies was observed for SARS-CoV-2. After 10 min, the infectious viral content was decreased by 98.2% reaching 100% inactivation after 30 min whereas the SARS-CoV-2 RNA load was decreased of 1.5 log10 after 30 min. Thus, despite only a partial decrease of viral RNA, SARS-CoV-2 infectivity was completely inactivated by the system in 30 min. These results support the idea that this system could be exploited to achieve SARS-CoV-2 inactivation not only for liquids but also for air purification in indoor environments.
Nanoclusters, SARS-CoV-2, Tungsten, coronavirus, photocatalytic,