ИСТИНА

Modern photosensitizers for antitumor therapy must meet a number of strict requirements: high quantum yield of free radicals, selective accumulation in tumors, low dark toxicity. Fullerenes can be subject of interest due to their ability to transition to triplet state upon excitation by light with high quantum yield. Depending of solvent polarity, they efficiently generate singlet oxygen or superoxide anion radical, thus they can cause destruction of cells. Medicinal application of fullerenes is restricted because of their weak absorbance in the red spectral range while this range is the most suitable for photodynamic therapy (PDT) due to high tissue penetration. Combination of high quantum yield with excitation by the light of long wave range can be achieved through binding of a fullerene with a dye with required excitation range that could transfer excitation energy to fullerene. Recently, a number of non-covalent complexes and covalent conjugates of water soluble fullerene derivatives with fluorescent dyes were synthesized. Photochemical activity of these compounds proved to be independent on quantum yield of a dye triplet state; and the energy transfer to fullerene occurs from singlet excited levels. These findings allow us to extend the possibilities for development of photosensitizerd since, at present, only triplet-excited dyes are used for PDT. New compounds combine features necessary for promising photosensitizers. They are water soluble but, due to amphiphilicity, they can interact with membranes; they absorb long-wave light but exhibit high photochemical activity; they can cause destruction of DNA and cells. Original data on physicochemical properties of hybrid fullerene-based structures, as well as their potential as perspective PDT agents will be presented.