X-Ray-Facilitated Redox Cycling Of Nanozyme Possessing Peroxidase-Mimicking Activity For Reactive Oxygen Species-Enhanced Cancer Therapy

Nanomaterials with shifting or mixed redox states is one of the most common studied nanozyme with peroxidaselike activity for chemodynamic therapy (CDT), which can decompose hydrogen peroxide (H2O2) of tumor microenvironment into highly toxic reactive oxygen species (ROS) by a nano-catalytic way. However, most of them exhibit an insufficient catalytic efficiency due to their dependence on catalytic condition. Herein, a potential methodology is proposed to enhance their enzymatic activity by accelerating the redox cycling of these nanomaterials with shifting or mixed redox states in the presence of X-ray. In this study, the nanocomposite consisting of SnS2 nanoplates and Fe3O4 quantum dots with shifting or mixed redox states (Fe2+/Fe3+) is used to explore the strategy. Under external X-ray irradiation, SnS2 cofactor as electron donor can be triggered to transfer electrons to Fe3O4, which promotes the regeneration of Fe2+ sites on the surface of the Fe3O4. Consequently, the regenerated Fe2+ sites react with the overexpressed H2O2 to persistently generate ROS for enhanced tumor therapy. The designed nanocomposite displays the synergistic effects of radiotherapy and CDT. The strategy provides a new avenue for the development of artificial nanozymes with shifting or mixed redox states in precise cancer treatments based on X-ray-enhanced enzymatic efficacy.