ИСТИНА

With a number of unique physical and chemical properties, water soluble metal phthalocyanines (MPcs) have found practical application not only as dyes, but as modern functional materials in nonlinear optics, as gas sensors, catalysts, photosensitizers. In addition to anticancer photodynamic therapy (PDT), the photosensitizing properties of MPCs are of increasing interest for photodynamic inactivation of drug resistant strains of pathogenic microorganisms for therapeutic purposes as well for water sterilization. These compounds act via type II photodynamic reactions, involving the formation of cytotoxic singlet oxygen (1O2). Inexpensive broadband lamps are favorable sources to activate photosensitizers used for disinfection or treatment of skin infections. However, the light absorption properties of MPcs are characterized by intensive Q-bands in far red region with a maximum near 680 nm and rather low absorption of other visible light wavelengths. Using the methods of steady-state and time-resolved fluorescent spectroscopy we found that semiconductor nanocrystals (quantum dots, QD) can be used to increase the effective absorption crossection of zinc phthalocyanines (ZnPcs). In a mixture ZnPcs and QDs form stable hybrid complexes due to electrostatic interactions, the fluorescence of the QD in such hybrid complexes is strongly quenched due to the transfer of the absorbed energy to the ZnPcs. We discuss Forster’s inductive resonance mechanism as a possible way of energy transfer in donor–acceptor pairs. Calculations based on the experimental data show enhancement of ZnPcs fluorescence up to 140 % due to efficient energy migration from QDs. The treatment of genetically engineered bioluminescent strain of E. coli cells with solutions of hybrid structures and irradiation with white light lead to efficient inactivation of bacteria.