Glucose-responsive mesoporous prussian blue nanoprobes coated with ultrasmall gold and manganese dioxide for magnetic resonance imaging and enhanced antitumor therapy

To achieve safe and efficient tumor therapy, it was a powerful strategy of constructing an intelligent tumor microenvironment (TME)-responsive nanoprobe. In this study, by coating ultrasmall gold nanoparticles (AuNPs) and manganese dioxide (MnO2) on mesoporous prussian blue (MPB), MPB@AuNPs@MnO2 nanoprobe with H2O2 self-generation was developed for magnetic resonance (MR) imaging, photothermal therapy (PTT) and enhanced chemodynamic therapy (CDT). The results indicated that the prepared MPB@AuNPs@MnO2 possessed uniform size and good biocompatibility. Using glucose-responsive self-supplying H2O2 of ultrasmall AuNPs, and glutathione (GSH)-responsive Mn2+ release from MnO2 degradation, the accelerated hydroxyl free radicals (·OH) generation efficiency (80.0 % to 90.84 %) and enhanced MR relaxation (1.93 to 9.96 mM−1·s−1) were achieved. Importantly, the prepared MPB@AuNPs@MnO2 exhibited excellent photothermal performance with a photothermal conversion efficiency of 42.62 %. Moreover, the intracellular H2O2/·OH generation was demonstrated, and the in vitro CDT/PTT was enhanced, by which the cell viability was reduced to 6.4 %, stronger than 18.8 % of MPB@MnO2. By modeling MDA-MB-435 tumor-bearing nude mice, the combined CDT/PTT of MPB@AuNPs@MnO2 nanoprobe greatly inhibited the tumor growth, and after 15 days, the tumor completely disappeared. This work provided a promising strategy to develop TME-responsive self-supplying H2O2 nanoprobe, achieving MR imaging and enhanced antitumor efficacy.