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 (H 2 O 2 ) and unsuitable pH value limited its application. Herein, a tumor microenvironment (TME) responsive multifunctional nanoprobe with self-accelerating cascade catalysis (MPB@CeO 2 -GOx) was developed for enhanced catalytic therapy, in which ultrasmall cerium oxide (CeO 2 ) and glucose oxidase (GOx) were modified on mesoporous Prussian blue (MPB). The developed MPB@CeO 2 @-GOx nanoprobes exhibited the dual-nanozyme activity of catalase (CAT) and peroxidase (POD), by which the O 2 and hydroxyl radical (·OH) were generated by Ce 4+ and Ce 3+ . Moreover, the sufficient O 2 promoted the glucose consumption of GOx , and the generated H 2 O 2 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 CeO 2 . Compared with MPB@CeO 2 , the cell survival reduced from 20.8% to 3.8%, and the tumor growth was completely inhibited. Therefore, by self-supplying O 2 /H 2 O 2 and reducing pH value, the developed MPB@CeO 2 -GOx nanoprobes with self-accelerating cascade reactions achieved PTT and enhanced catalytic therapy against breast cancer.