Carbon-coated magnetite nanoclusters with NIR-II absorbance for imaging-guided photothermal-chemodynamic synergistic therapy

Chemodynamic therapy (CDT) is an emerging therapeutic modality to treat cancer based on magnetite nanozymes. However, the low catalytic capacity and single-mode treatment limit its therapeutic efficacy. Herein, a kind of carbon-coated magnetite nanoclusters (CCMNCs) with high absorbance in the second near-infrared (NIR-II) window has been developed for NIR-II photothermal-enhanced chemodynamic anti-cancer therapy. Such CCMNCs with a size of about 58 nm were synthesized by a one-step solvothermal method using ferrocene as a single precursor. The CCMNCs not only serve as a contrast agent for tumor-targeted magnetic resonance imaging, but also absorb and convert NIR-II irradiation into local heat for the hyperthermic killing of cancer cells. The ferrous and iron ions produced from the CCMNCs in acid solution catalyze the Fenton reaction to generate hydroxyl radicals (·OH) for CDT and reduce the intracellular glutathione that exerts as free radical scavengers. The reported CCMNCs demonstrate a superior therapeutic efficacy through the synergistic effect of a combined chemodynamic-photothermal treatment.