Cerium dioxide based nanoprobe with self-accelerating cascade catalysis for enhanced catalytic therapy by self-generating H2O2 and reducing pH value

Nanocatalytic medicine was attracting considerable attention, owing to the specific treatment by the intrinsic chemical reactions within tumors. However, the insufficient hydrogen peroxide (H2O2) and unsuitable pH value limited its application. Herein, a tumor microenvironment (TME) responsive multifunctional nanoprobe with self-accelerating cascade catalysis (MPB@CeO2-GOx) was developed for enhanced catalytic therapy, in which ultrasmall cerium oxide (CeO2) and glucose oxidase (GOx) were modified on mesoporous Prussian blue (MPB). The developed MPB@CeO2@-GOx nanoprobes exhibited the dual-nanozyme activity of catalase (CAT) and peroxidase (POD), by which the O2 and hydroxyl radical (·OH) were generated by Ce4+ and Ce3+. Moreover, the sufficient O2 promoted the glucose consumption of GOx, and the generated H2O2 and gluconic acid further enhanced the catalytic therapy by reducing pH value, by which ·OH yield increased by 26.21%. In addition, the photothermal effect of MPB also significantly improved the POD activity of CeO2. Compared with MPB@CeO2, the cell survival reduced from 20.8% to 3.8%, and the tumor growth was completely inhibited. Therefore, by self-supplying O2/H2O2 and reducing pH value, the developed MPB@CeO2-GOx nanoprobes with self-accelerating cascade reactions achieved PTT and enhanced catalytic therapy against breast cancer.