The interaction between hypericin and supported lipid bilayers mimicking coronavirus envelopes.
Mariangeli M., Dante S., Delcanale P., Abbruzzetti S., Diaspro A., Viappiani C., Bianchini P.
Biological membranes are one of the most important self-assembled structures in nature. They provide many functional and protective features for cells and have a fundamental role in enveloped virus infectivity. The targeting of the viral envelope is an emerging strategy in the development of broad-spectrum antivirals, also based on photosensitizers (PS). PS are molecules that trigger the production of singlet oxygen upon photo-excitation. Singlet oxygen is a strong oxidant capable of damaging biomolecules, such as phospholipids. For a few decades, PS have been employed in a therapy called Photodynamic Therapy (PDT) mostly against cancer cells, but also against bacteria and viruses. We focused on hypericin (Hyp), a photosensitizer that was found to inactivate enveloped viruses, including SARS-CoV-2, not only upon photo-excitation, but also in dark conditions. To study the effects of hypericin on a viral envelope we used supported lipid bilayers, an excellent model system for membranes, with a lipid mixture to mimic the viral envelope. By performing AFM microscopy and AFM-STED correlative nanoscopy (Hyp is fluorescent), we reported a noticeable effect of Hyp at various concentrations.