High aspect ratio plasmonic Au/Ag nanorods-mediated NIR-II photothermally enhanced nanozyme catalytic cancer therapy

Chemodynamic therapy (CDT) is based on the endogenous generation of cytotoxic hydroxyl free radicals (·OH) with high specificity and selectivity between cancer and normal cells. However, its efficacy is often limited by the relatively deficient catalytic activity of nanozymes in the tumor microenvironment (TME). Therefore, the combination of CDT with other strategy to realize synergistic therapy is necessary. Herein, a versatile plasmonic Au/Ag nanorods (abbreviated as Au/Ag NRs) via anisotropic Ag overgrowth on Au nanobipyramids was rationally devised to achieve synergistic nanozyme catalytic therapy and near infrared II (NIR-II) light induced photothermal therapy (PTT) with the guidance of computed tomography (CT) imaging. As TME contains high concentrations of H+ and H2O2, Au/Ag NRs exhibited peroxidase (POD) activity to catalyze H2O2 to produce ·OH, inducing cancer cell death. Meanwhile, Au/Ag NRs showed a preeminent NIR-II photothermal effect. More importantly, the enhanced ·OH generation by in-situ heating up resulting from PTT could conversely inhibit the expression of heat shock proteins (HSPs) to abate their resistance to PTT, realizing self-augmented synergistic effect. The NIR-II photothermally enhanced nanozyme catalytic cancer therapy validly inhibited the cancer proliferation, as demonstrated via both cell and animal assays. Moreover, ideal high-contrast CT imaging was realized, owing to the X-ray attenuation capability of elemental Au. The multifunctional Au/Ag NRs hold potential in oncotherapy with imaging capability, high efficiency and low side effects.