Antiviral photodynamic therapy: Inactivation and inhibition of SARS-CoV-2 in vitro using methylene blue and Radachlorin

Research performed at:

1. State Research Center of Virology and Biotechnology «Vector» Rospotrebnadzor, Koltsovo, Novosibirsk Region, 630559, Russia

2. Novosibirsk State University, 1, Pirogova Str., Novosibirsk, 630090, Russia

3. Institute of Laser Physics of the Siberian Branch of the Russian Academy, 15, Ac. Lavrentieva Ave., Novosibirsk, 630090, Russia

4. N.N. Petrov National Medical Research Center of Oncology, Pesochny, 68, Leningradskaya Str., Saint-Petersburg, 197758, Russia

The authors:

Victor A. Svyatchenko, Sergey D. Nikonov, Alexander P. Mayorov, Mark L. Gelfond, Valery B. Loktev

Recently, the COVID-19 pandemic has spread globally, necessitating the development of new methods for its prevention and treatment. The purpose of this study was to evaluate the antiviral activity of photodynamic therapy (PDT) against SARS-CoV-2 in vitro.

Methods: Vero E6 cells and SARS-CoV-2 isolated in Russia were used for PDT with methylene blue (MB) and Radachlorin. A continuous laser with wavelength λ = 662 nm in doses of 16 J/cm2 and 40 J/cm2 laser irradiation was used for PDT of a viral suspension and SARS-CoV-2-infected cells. The direct cytopathogenic effect of SARS-CoV-2 was evaluated via light microscopy to calculate the TCID50 in the samples and perform statistical analysis. Conclusion: PDT shows high antiviral activity against SARS-CoV-2 when combined with MB and Radachlorin in vitro.