Fig. 2.

Photosensitizers ZnPc5K and ce6 effectively inactivated SARS-CoV-2 live virus upon LED illumination. (A) Dose response curve of viral inactivation upon photodynamic treatment. The SARS-CoV-2 with a dose of 0.02 multiplicity of infection (MOI) was incubated with serially diluted photosensitizer and illuminated, followed by addition to Vero cells and further incubation for 48 h. The viral yield in the cell supernatant was quantified by qRT-PCR. (B) Immunofluorescence microscopic images of virus infection upon treatment of ZnPc5K and ce6 at the indicated concentrations with illumination showed the efficacy of photosensitizers to virus and safety to host cells. The fluorescence images were taken at 48 h post infection (h.p.i). Scale bar, 200 μm. Cells were stained with the viral protein (green) and nuclei (blue). (C) Cytotoxicity of ZnPc5K or ce6 to Vero cells was measured by CCK-8 assay and showed almost no phototoxicity up to 5 μM with a light dose of 0.48 J/cm².