Interplay of phosphate and carbonate ions with flavin photosensitizers in photodynamic inactivation of bacteria

• DOI: 10.1371/journal.pone.0253212
• Publication Date: 2021-06-11T17:31:40Z
• Authors: Daniel Bernhard Eckl; Stefanie Susanne ...; Laura Schottenhaml; Anja Eichner; Rudolf Vasold; Andreas Späth; Wolfgang Bäumler; Harald Huber
• Keywords: Flavin mononucleotide

Photodynamic inactivation (PDI) of pathogenic bacteria is a promising technology in different applications. Thereby, photosensitizer (PS) absorbs visible light and transfers the energy to oxygen yielding reactive species (ROS). The produced ROS are then capable killing microorganisms via oxidative damage cellular constituents. Among other PS, some flavins producing cationic already successfully applied PDI. When PDI used for example on tap water, PS like will encounter various ions small organic molecules which might hamper efficacy Thus, impact carbonate phosphate using two (FLASH-02a, FLASH-06a) was investigated Staphylococcus aureus Pseudomonas aeruginosa as model organisms. Both were inactivated vitro at low exposure 0.72 J cm - 2 . Upon irradiation, FLASH-02a reacts single substances presence or phosphate, whereas photochemical reaction FLASH-06a more unspecific. DPBF-assays indicated that decreased generation singlet both flavins. could be easily by least one with up 6 log 10 steps cell counts ion concentrations. Using constant radiation -2 , somewhat medium concentrations but reached almost zero high Depending application PDI, unavoidable. Only upon irradiation such may attack molecule reduce Our results indicate can still lead efficient reduction bacterial cells when flavin based PS.