Unlocking the potential of iridium-osmium carbolong conjugates: a high-performance photocatalyst for melanoma therapy

Structural modification and optimization of photosensitizers can improve their photophysical properties, thereby enhancing the therapeutic efficacy of photodynamic therapy (PDT). Here we designed and synthesized a novel bimetallic iridium-osmium complex Ir-Os1 as a photosensitizer for PDT of melanoma under 550 nm ight-emitting diode (LED) light irradiation. Compared with the mononuclear metal complexes, Ir-Os1 exhibited a significantly higher molar absorption coefficient, resulting in outstanding reactive oxygen species (ROSs) generation and improved photocatalytic oxidation of NADH during the irradiation process. Both in vivo and in vitro studies demonstrated effective inhibition of melanoma cell growth and excellent photocytotoxicity under light irradiation. More interestingly, Ir-Os1 was able to hinder the production of bioenergetic substances in cancer cells via the glycolytic pathway, leading to adenosine triphosphate (ATP) starvation-induced cell death and ultimately disrupting cellular energy metabolism. This study suggests that a bimetallic strategy can enhance the photocatalytic efficiency.