In vitro photodynamic efficacy of polycationic photosensitizers based on polycationic phthalocyanines

Polycationic photosensitizers have previously demonstrated high in vitro efficacy against lung cancer cells, including cancer stem cells, and low dark cytotoxicity. Polycationic phthalocyanines have high quantum yield of singlet oxygen and photostability. In addition, it is possible to relatively simply introduce different metal-complexing agents and substituents into phthalocyanine macrocycles, which enables varying their photophysical characteristics. In this work, we studied photophysical properties of photosensitizers based on polycationic phthalocyanine derivatives with different chemical structure with strong absorption in the long wavelength region (680–690 nm). The studied photosensitizers exhibit negligible aggregation in the 1–100 μM concentration range and show very high phototoxicity in an in vitro study on A549 lung carcinoma cells (IC 50 of 60–100 nM for ZnPcChol 8 and 100–300 nM for 4αZnPc4 + and 4αβZnPc4 + , depending on the light dose), and low dark cytotoxicity.