Binding and photodynamic action of the cationic zinc phthalocyanines with different types of DNA toward understanding of their cancer therapy activity.

Two cationic zinc phthalocyanines have been tested for their interactions with several DNA secondary structures. Despite different aggregation properties, both phthalocyanines bind to DNA in monomeric forms. The strong photodynamic activity of phthalocyanines was demonstrated by in vitro experiments and correlate well with high singlet oxygen yields determined experimentally with 1,3-diphenylisobenzofurane. Both phthalocyanines accumulate in the cell cytoplasm prior to radiation; however, only the octacationic photosensitizer was observed in the cell nuclei after irradiation.