Cell‐Membrane Staining Properties and Photocytotoxicity of a Ruthenium(II) Photosensitizer

Organelle-targeting photosensitizers have attracted increasing attention in the development of drugs for photodynamic therapy because they can efficiently induce cellular functional disorder upon light irradiation. In this work, we reported a ruthenium(II) complex bearing two lipophilic carbon chains which specifically binds to the cell membrane. Light irradiation on the complex-treated cells caused an increase of intracellular reactive oxygen species. The photocytotoxicity of the complex toward HeLa cells were evaluated via the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. A high dose (3 mu m) of the complex induced apoptotic cell death by photogeneration of intracellular reactive oxygen species. A low dose (0.25 mu m) of the complex did not cause noticeable cell death but increased the permeability of the cell membrane upon light irradiation.