Photosensitized generation of singlet oxygen in aerosol jet and on biological surfaces

Photodynamic inactivation (PDI) is known to be effective for treatment of various viral and bacterial infections. In view of the current COVID-19 pandemic the search for therapeutic modalities efficient against this particular virus is of high demand. PDI with photosensitizer solution applied in the oral cavity and throat by flushing and gargling was already demonstrated to be promising for reduction of viral load at early stages of COVID- 19 infection. In this report we present experimental results on detection of singlet oxygen generated using Radachlorin photosensitizer in nebulizer aerosol jet and on different biological surfaces modeling, in particular, mucous membranes of the respiratory tract. The lifetimes of singlet oxygen and photosensitizer triplet state were shown to depend noticeably on the surface type. Moreover the surface type was found to be strongly affecting the photosensitizer photobleaching kinetics, with mucous samples providing much slower bleaching.