Magnesium alloy implant with photothermal-enhanced ferroptosis towards a multimodal therapy strategy for osteosarcoma

Osteosarcoma is a highly malignant tumor that severely affects the physical and mental health of adolescents. Photothermal synergistic catalytic therapy is regarded as an effective and innovative strategy to eliminate tumor cells and restore bone tissue. Herein, an intelligent and anti-corrosion non-drug-loading platform, based on a dopamine-chelated iron composite coating (FeOOH/PDA-Fe), is constructed on osteogenic magnesium alloys. The prepared films function as an iron "sandwich", which progressively enhance the corrosion resistance of Mg alloy, and pump iron ions loaded under near-infrared (NIR) irradiation and in the tumor microenvironment, but remain stable in the normal environment. Efficient photothermal therapy-driven tumor apoptosis of modified Mg alloys within the NIR window due to the strong ligand-to-metal charge transfer between intermediates of dopamine and transition metal iron oxidation. In vitro and in vivo studies reveal the synergistic mechanism of photothermal treatment on catalytic therapy for osteosarcoma of the prepared coating, and the mechanism by which the synergistic therapy re-activates the innate immune response by inducing tumor immunogenic death. The modified Mg alloys that combine effective corrosion resistance, highly efficient tumor ablation without drug resistance, and innate immune response re-activation, are likely a point-to-point solution for the comprehensive therapeutic needs of osteosarcoma.