Sub-nano molybdenum oxide nanorings as amplified atomic efficiency sonosensitizers for highly efficient sonodynamic...

Sub-nanometer structured molybdenum oxide nanorings (MoO_x-S NRs) are designed as a dual-functional nano-sensitizer and single-atom nano-enzyme, used for ultrasound-enhanced hydrogen therapy. The unique sub-nanometer structure provides unsaturated coordination sites and sulfur groups, while its high surface energy generates delocalized electrons, thereby optimizing the activation energy and enhancing the tumor Russell-type catalytic therapy mediated by singlet oxygen under hypoxic conditions. Compared with traditional MoO_x NPs, the MoO_x-S NRs significantly increase the generation of reactive oxygen species and hydrogen triggered by ultrasound. Under ultrasound action, the MoO_x-S NRs produce cytotoxic singlet oxygen and superoxide radicals, damage cancer cells and inhibit tumor growth. Moreover, the released hydrogen further penetrates the cell nucleus, regulating the tumor microenvironment and disrupting the inflammatory pathways to alleviate tumor-related inflammation. This work demonstrates an efficient strategy for using sub-nanometer MoO_x-S NRs combined with the Russell-type catalytic and hydrogen therapy, providing a new perspective for cancer nanomedicine.