Metal-organic frameworks-derived bimetallic nanozyme platform enhances cytotoxic effect of photodynamic therapy in hypoxic cancer cells

Photodynamic therapy (PDT) is increasingly accepted as a cancer treatment because it can target the tumor precisely and treat it noninvasively. The therapeutic effect of PDT is generally affected by three parameters: the light, the photosensitizers (PSs), and the local oxygen, where the performance of the PSs with light is greatly affected by the availability of local oxygen. However, hypoxia is one of the typical characteristics of the microenvironment in solid tumors, which renders the efficacy of PDT in cancer treatment. Here, we introduced a novel nanozyme platform, which composed of metal-organic frameworks (MOF) derived materials and could directly load the PSs. The nanozyme could generate oxygen by catalyzing H₂O₂, which enhanced the production of reactive oxygen species (ROS) and resulted in an improved cytotoxic effect of the PSs. We showed that, especially under the hypoxic environment, this nanozyme could alleviate the hypoxic situation by generating oxygen in the H₂O₂ solution and further improved the therapeutic effect of PDT consequently. In conclusion, this nanozyme platform allows the loading of PSs with ease and can catalyze H₂O₂ to generate oxygen to enhance the effect of PDT for cancer treatment in both normoxic and hypoxic environments.