04 Sep 2021
Photodynamic inactivation of pathogenic microorganisms can be successfully used to eradicate pathogens in localized lesions, infected liquid media, and on various surfaces. This technique utilizes the photosensitizer (PS), light, and molecular oxygen to produce reactive oxygen species that kill pathogens. Here, we used the PS, water soluble octakis(cholinyl)zinc phthalocyanine (Zn-PcChol
), to inactivate an initial 4.75-5.00 IgTCID50/mL titer of SARS-CoV-2, thereby preventing viral infection when tested in Vero E6 cell cultures. Zn-PcChol
in a minimally studied concentration, 1 µM and LED 3.75 J/cm
, completely destroyed the infectivity of SARS-CoV-2. To detect possible PS binding sites on the envelope of SARS-CoV-2, we analyzed electrostatic potential and simulated binding of Zn-PcChol
to the spike protein of this coronavirus by means of Brownian dynamics software, ProKSim (Protein Kinetics Simulator). Most of the Zn-PcChol
molecules formed clusters at the upper half of the stalk within a vast area of negative electrostatic potential. Positioning of the PS on the surface of the spike protein at a distance of no more than 10 nm from the viral membrane may be favorable for the oxidative damage. The high sensitivity of SARS-CoV-2 to photodynamic inactivation by Zn-PcChol
is discussed with respect to the application of this PS to control the spread of COVID-19.