A porphyrin–ruthenium photosensitizer as a potential photodynamic therapy agent

The binding constant of a novel ruthenium–porphyrin to calf thymus DNA is reported. In addition, the ruthenium–porphyrin photocleaves circular plasmid DNA in buffered solutions when irradiated with a 50 W tungsten-halogen lamp. The ruthenium–porphyrin shows the ability to diffuse into normal and skin cancer cells and over a 6 day period in the absence of light shows no toxicity, however, complete cell death is observed when these cells are irradiated for 1 h with a 60 W tungsten lamp.