Platinum-Based Azadipyrromethane Complexes for Targeted Cancer Phototherapy: Synthesis, Properties, and Therapeutic Application

Cancer remains a major global health challenge, necessitating the development of alternative therapies that minimize side effects and overcome drug resistance associated with conventional treatments. In this study, it reports the synthesis and characterization of a series of platinum(II) complexes based on azadipyrromethene (ADPM) ligands as novel photosensitizers for photodynamic therapy (PDT). These complexes are designed to enhance light absorption and photochemical activity through the incorporation of heavy atoms. Their photophysical properties-including absorption spectra, fluorescence emission, and singlet oxygen generation efficiency-are systematically investigated. The complexes exhibited strong absorption in the visible region and high singlet oxygen yields, indicating their suitability for PDT applications. In vitro assays using several cancer cell lines demonstrate low cytotoxicity under dark conditions, whereas light activation induces a significant cytotoxic response. Flow cytometry analysis further confirms that the treatment induces apoptotic cell death. These effects were found to be both light- and concentration-dependent. Overall, this study's results demonstrate the potential of these platinum-ADPM complexes as effective and selective PDT agents, offering a promising strategy for the development of safer and more targeted cancer therapies.