H2O2 self-sufficient nanoplatform based on CeO2 QDs decorated MgO2 nanosheet for amplified chemodynamic therapy

Chemodynamic therapy (CDT), which employs Fenton/Fenton-like agents to decompose hydrogen peroxide (H2O2) into toxic hydroxyl radical (•OH) to induce cancer cell apoptosis and necrosis, holds great promise in tumor therapy due to its high selectivity. Nevertheless, its efficiency is impaired by the insufficient intracellular H2O2 concentration and/or the insensitive response of Fenton/Fenton-like agents to the slightly acid tumor microenvironment (pH∼7.0-6.5). Herein, we develop a novel CDT reagent based on CeO2 quantum dot (QD) decorated MgO2 nanosheets engineered with cascade reactions to boost the intracellular H2O2 level and high pH-activated (pH = 6.5) characteristic for an enhanced CDT. Under the tumor microenvironment (pH = 6.5), MgO2 nanosheets that are highly reactive can react with H2O to produce nontoxic Mg2+ and abundant H2O2, boosting the intracellular H2O2 level. The self-generated H2O2 is subsequently converted into •OH by CeO2 QD, which is served as a relatively high pH-activated (pH = 6.5) Fenton-like agent. The sufficient intracellular H2O2 supply and sensitive response to the slightly acid tumor sites significantly improve the Fenton reaction, leading to the excellent in vivo CDT results with tumor growth inhibition effect. Our work presents a distinctive paradigm for self-boosting CDT efficacy.