Metal-Ligand Complexes as Multifunctional Platforms for Photo-Activated Cancer Therapy

Metal-ligand complexes have emerged as versatile platforms for photo-activated therapy (PAT) for cancer, including photothermal therapy, photodynamic therapy, and photo-activated chemotherapy. This review explores the unique optical properties and tunable characteristics of these complexes, which enable effective reactive oxygen species generation and near-infrared light absorption for targeted cancer cell destruction. Metal-ligand complexes are classified based on their ligands and metal ions. The ligands include tetrapyrrolic structures, polypyridine, and polyphenols, while the metal ions comprise transition and noble metals. Their individual contributions to enhancing therapeutic efficacy are also explored. Fundamental interactions, including ligand-to-metal charge transfer and metal-ligand coordination, are examined. These interactions significantly influence the photoreactivity and biocompatibility of the complexes. Recent advances integrating metal-ligand complexes with other modalities, such as chemo-phototherapy and immunotherapy, are highlighted. These combinations offer promising approaches for synergistic tumor eradication. The challenges of ligand diversity, delivery optimization, and the underexplored mechanisms in PAT are also discussed. By integrating recent progress and prospective applications, this review emphasizes the critical importance of metal-ligand complexes in innovating cancer theranostic technologies.