Engineered Bacteria Labeled with Iridium(III) Photosensitizers for Enhanced Photodynamic Immunotherapy of Solid Tumors

Despite metal‐based photosensitizers showing great potential in photodynamic therapy for tumor treatment, the application of the photosensitizers is intrinsically limited by their poor cancer‐targeting properties. Herein, we reported a metal‐based photosensitizer‐bacteria hybrid, Ir‐HEcN , via covalent labeling of an iridium(III) photosensitizer to the surface of genetically engineered bacteria. Due to its intrinsic self‐propelled motility and hypoxia tropism, Ir‐HEcN selectively targets and penetrates deeply into tumor tissues. Importantly, Ir‐HEcN is capable of inducing pyroptosis and immunogenic cell death of tumor cells under irradiation, thereby remarkably evoking anti‐tumor innate and adaptive immune responses in vivo and leading to the regression of solid tumors via combinational photodynamic therapy and immunotherapy. To the best of our knowledge, Ir‐HEcN is the first metal complex decorated bacteria for enhanced photodynamic immunotherapy.