Multicomponent coordination-driven self-assembled metallacycles as efficient photosensitizers for photodynamic therapy

Novel TPE-based metallacycles were developed as efficient supramolecular photosensitizers, offering new opportunities for optimizing photodynamic therapy and advancing its biomedical applications. • In this study, three metallacycles ( 4a–4c ) were constructed as integrated platforms for enhanced PDT via a multicomponent coordination-driven self-assembly strategy. These metallacycles integrate AIE characteristics of TPE with the electron accepting ability of viologen derivatives, while the incorporation of chalcogen atoms modulates electronic coupling and conjugation, thereby enhancing electron transfer and photosensitization efficiency. Moreover, the cationic metallacycles promote preferential accumulation within tumor cells, further improving PDT efficacy. In vitro and in vivo assays confirmed that these compounds exhibited potent cytotoxicity against human colorectal cancer cell lines HCT116 and SW480 under light irradiation, with negligible dark toxicity. This self-assembly strategy enables the precise integration of multiple functional motifs, providing a promising supramolecular approach for advancing PDT and related biomedical applications.