BODIPY-Based Photothermal Agents with Excellent Phototoxic Indices for Cancer Treatment.

Here, we report six novel, easily accessible BODIPY-based agents for cancer treatment. In contrast to established photodynamic therapy (PDT) agents, these BODIPY-based compounds show additional photothermal activity and their cytotoxicity is not dependent on the generation of reactive oxygen species (ROS). The agents show high photocytotoxicity upon irradiation with light and low dark toxicity in different cancer cell lines in 2D culture as well as in 3D multicellular tumor spheroids (MCTSs). The ratio of dark to light toxicity (phototoxic index, PI) of these agents reaches striking values exceeding 830,000 after irradiation with energetically low doses of light at 630 nm. The oxygen-dependent mechanism of action (MOA) of established photosensitizers (PSs) hampers effective clinical deployment of these agents. Under hypoxic conditions (0.2% O