Rapid inactivation of SARS-CoV-2 by titanium dioxide surface coating

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission occurs via airborne droplets and surface contamination. Titanium dioxide (TiO2) coating of surfaces is a promising infection control measure, though to date has not been tested against SARS-CoV-2. Methods: Virus stability was evaluated on TiO2- TiO2–Ag (Ti:Ag atomic ratio 1:0.04)-coated 45 x mm ceramic tiles. After the tiles were stored for 2–4 months before use. We both SARS-CoV-2 Spike pseudotyped virions based lentiviral system, as well fully infectious virus. For former, tile inoculated with spike HIV-1 luciferase At intervals virus recovered from target cells infected. live virus, after illuminating 0–300 min followed by Vero E6 cells. % infected determined flow cytometry detecting nucleocapsid protein 24 h post-infection. Results: After 1 illumination pseudotyped viral titre decreased four orders magnitude. There no significant difference between TiO2 coatings. Light alone had effect viral viability. SARS-CoV-2, already significantly inactivated 20 illumination. 5 detectable active remained. Significantly, untreated still at post-addition Overall, coated 120 days previously able inactivate under ambient indoor lighting 87% reduction in titres 1h complete loss 5h exposure. Conclusions: In context emerging variants increased transmissibility, coatings could be an important tool containing particularly health care facilities where nosocomial rates are high.