Figure 3

Effects of culture media on the inactivation efficacy of SARS-CoV-2 at 280 nm DUV. (a) Plaque assays. Virus stocks were diluted with EMEM containing 2% FBS (EMEM) or PBS containing 2% FBS (PBS). The diluted samples were exposed to DUV-LED at 280 nm wavelength for various irradiation time periods (5, 15, and 30 s). The irradiated samples were appropriately diluted, if necessary, for plaque assays as described in Fig. 1b. Representative data (irradiation for 0 and 30 s) from six independent assays are shown. (b and c) Inactivation efficacy at various total doses of DUV-LED energy with (c) and without (b) normalization by transmittances. The transmittances of the culture media of the virus stock diluted with EMEM containing 2% FBS and that with PBS containing 2% FBS at 280 nm were 37.9% and 63.3%, respectively. Mean values (M) ± standard errors (SE) are shown (N = 6).