Overproduction of reactive oxygen species (ROS) within tumors can cause oxidative stress on tumor cells to induce death, which has motivated us to develop ROS-mediated tumor therapies, such as typical photodynamic therapy (PDT) and Fenton reaction-mediated chemodynamic therapy (CDT). However, these therapeutic modalities suffer from compromised treatment efficacy owing to their limited generation of highly reactive ROS in a tumor microenvironment (TME). In this work, a nanoscale iron-based metal-organic framework, MIL-101(Fe), is synthesized as a Fenton nanocatalyst to perform the catalytic conversion of hydroxyl radicals (·OH) from hydrogen peroxide (H2O2) under the acidic environment and as a biocompatible and biodegradable nanocarrier to deliver a 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) photosensitizer for light-activated singlet oxygen (1O2) generation. By coupling such chemodynamic/photodynamic effects, the photosensitizer-integrated nanoagents (MIL-101(Fe)@TCPP) could enable more ROS production within tumors to induce amplified oxidative damage for tumor-specific synergistic therapy. In vitro results show that MIL-101(Fe)@TCPP nanoagents achieve the acid-responsive CDT and effective PDT, and synergistic CDT/PDT provides an enhanced therapeutic effect. Ultimately, based on such synergistic therapy, MIL-101(Fe)@TCPP nanoagents cause a significant tumor growth inhibition in vivo without severe side effects, showing great potential for anti-tumor application.
Keywords: chemodynamic therapy; metal−organic framework; photodynamic therapy; porphyrin; tumor.