H 2 O 2 -independent chemodynamic therapy initiated from magnetic iron carbide nanoparticle-assisted artemisinin synergy.

Chemodynamic therapy (CDT) is a booming technology that utilizes Fenton reagents to kill tumor cells by transforming intracellular H 2 O 2 into reactive oxygen species (ROS), but insufficient endogenous H 2 O 2 makes it difficult to attain satisfactory antitumor results. In this article, a H 2 O 2 -free CDT technique with tumor-specificity is developed by using pH-sensitive magnetic iron carbide nanoparticles (PEG/Fe 2 C@Fe 3 O 4 NPs) to trigger artemisinin (ART) to in situ form ROS. ART-loaded PEG/Fe 2 C@Fe 3 O 4 NPs are fabricated for the enormous release of Fe 2+ ions induced by the acidic conditions of the tumor microenvironment after magnetic-assisted tumor enrichment, which results in the rapid degradation of the PEG/Fe 2 C@Fe 3 O 4 NPs and release of ART once endocytosed into tumor cells. In situ catalysis reaction between the co-released Fe 2+ ions and ART generates toxic ROS and then induces apoptosis of tumor cells. Both in vitro and in vivo experiments demonstrate that the efficient Fe-enhanced and tumor-specific CDT efficacy for effective tumor inhibition based on ROS generation. This work provides a new direction to improve CDT efficacy based on H 2 O 2 -independent ROS generation.