FeC2O4/g-C3N4 self-assemble nanorods regulate stimuli-responsive ferroptosis via photo-fenton mechanism

The exclusive Fenton activity of iron ions has initiated wide investigation into tumor microenvironment-activated tumor therapy owing to the production of toxic ·OH and extra oxygen for chemodynamic therapy (CDT) and photodynamic therapy (PDT) respectively. However, the sensitivity of the labile iron pool (LIP) is unsatisfactory even when iron ions are placed in the tumor microenvironment. Herein, we constructed ferrous oxalate (FeC2O4) self-assembled nanorods loaded with a graphitic carbon nitride (g-C3N4) photo-Fenton catalyst, which can catalyze H2O2 to continuously generate abundant ·OH under visible light irradiation. The FeC2O4 self-assembled nanorods also dramatically accelerated O2 production (catalase activity) to improve the PDT of C3N4. Furthermore, the photo-Fenton catalyst under excitation also open ion channels and release free iron to increase LIP to exploit the joint CDT and PDT. Characterizations proved the self-assembled nanorods outperformed conventional Fenton catalysts in terms of stability, photoelectric response performance and photo-Fenton catalytic ability, which can be ascribed to the optimized band structure and charge isolating capability. Remarkably, the self-assembled nanorods coated with g-C3N4 also showed excellent biocompatibility during the fluorescence tracing cell phagocytosis experiment, suggesting great in-vivo application potential. The results of enhanced generation of reactive oxygen species, reduction of glutathione, consumption of lipid peroxidation, and reduced cell viability verified the typical ferroptosis mechanism of the FeC2O4/g-C3N4 self-assemble system as-developed. These results demonstrate the great potential of the biocompatible self-assembly photo-Fenton system for rational control of tumor behaviors.