Bismuth-based porphyrin metal organic framework specific nano-inducer for tumor photoimmunotherapy

Photoimmunotherapy has gained significant attention due to its remarkable therapeutic effects, combining the benefits of photodynamic and photothermal therapies with systemic immune responses, making it a promising approach for treating metastatic cancers. Porphyrins are effective photosensitizers, but their poor water solubility and tendency to aggregate often result in reduced activity. A bismuth-based metal-organic framework (MOF) is fabricated as a specific inducer for tumor photoimmunotherapy. Tetrakis(4-carboxyphenyl)porphyrin (TCPP) serves as the organic ligand, forming MOF nanosheets, referred to as Bi-TCPP. Bi-TCPP exhibits enhanced it-it stacking and superior semiconductor performance compared to TCPP, leading to improved reactive oxygen species (ROS) generation and better water dispersibility. Under 635 nm light irradiation, Bi-TCPP exhibits a high photothermal conversion efficiency of 41.5%. Moreover, Bi-TCPP depletes glutathione (GSH) within the tumor microenvironment. During phototherapy, Bi-TCPP induces pyroptosis, promoting the release of immune-related factors, thereby enhancing immune responses by triggering immunogenic cell death and inhibiting tumor growth and metastasis. Therefore, Bi-TCPP, synthesized via a straightforward approach, demonstrates the ability to selectively induce apoptosis, necrosis, and pyroptosis both in vitro and in vivo, activating immune responses and facilitating photoimmunotherapy against tumors.