Ferric oxide nanosheet-engineered Mg alloy for synergetic osteosarcoma photothermal/chemodynamic therapy

Osteosarcoma(OS)is a malignant tumor with a high rate of recurrence.Recently,biodegradable Mg-based implants have become a new therapeutic platform for bone-related diseases.However,poor biosafety and deficient intelligent tumor-killing ability of Mg-based implants are still the main challenges for the pre-cise treatment of OS.Herein,based on the excellent catalytic and photothermal conversion properties of nanozyme ferric oxide(Fe_(3)O_(4)),a novel two-step hydrothermal method for in situ preparation of Fe_(3)O_(4)nanosheets on the surface of plasma electrolytic oxidation(PEO)-treated Mg alloy using Mg-Fe layered double hydroxides(Mg-Fe LDH)as precursor was proposed.Compared with Mg alloy,there were no obvious corrosion cracks on the surface of Fe_(3)O_(4)nanosheets-coated Mg alloy(Fe_(3)O_(4)-NS)immersed in 0.9 wt.%NaCl for 14 days,which demonstrated the corrosion resistance of Mg alloy was significantly enhanced.Cytocompatibility experiments and hemolysis assay confirmed the great biocompatibility of Fe_(3)O_(4)-NS,especially,hemolysis ratio was lower than 1%.Meanwhile,Fe_(3)O_(4)-NS presented excellent cat-alytic oxidation capacity in the presence of H_(2)O_(2),and its temperature can significantly increase from 27℃to approximately 56℃under NIR irradiation.Therefore,intelligent responsive Fe_(3)O_(4)nanosheets-engineered Mg-based implants demonstrated excellent antitumor properties in vivo and in vitro due to their photothermal and chemodynamic synergetic effects.This study provides a novel approach for the preparation of Fe_(3)O_(4)coatings on the surface of Mg alloys and a new strategy for the treatment of OS.