A homologous-targeting "nanoconverter" with variable size for deep tumor penetration and immunotherapy

Dual-activity nanozyme to initiate tandem catalysis for doubly enhancing ATP-depletion anti-tumor therapy

Nanozymes can regulate metabolism to achieve precise anti-tumor therapy. However, the application of nanozymes with single catalytic properties is limited by complex tumor microenvironment (TME). Herein, we report a rarely discovered nanozyme ruthenium (Ru), which has double catalytic activity of glucose-oxidase-like (GOx-like) activity and peroxidase-like (POD-like) activity. Importantly, the GOx-like activity of Ru was proposed for the first time, which can catalyze glucose and O₂ to product H₂O₂. And then, Ru nanozyme can connect the tandem catalysis to enhance various tumor therapy. Firstly, the atovaquone (ATO) and Ru NPs were covered with a hybrid membrane of tumor cells and liposomes to obtain Ru@ATO-Lip/M with homologous targeting. Due to the enhanced permeability and retention (EPR) effect and the tumor targeting, the Ru@ATO-Lip/M NPs could be efficiently delivered to tumor and taken up by tumor cells. Subsequently, the acidic environment of tumor activated Ru to catalyze H₂O₂ producing OH (Fenton-like reaction). Meanwhile, newly discovered ability of Ru catalyzed glucose and O₂ to produce gluconic acid and H₂O₂, which provided sufficient substrates (H₂O₂) for continuously generating more OH. Therefore, Ru nanozyme aggravated the starvation and chemodynamic therapy (CDT). Further, ATO improved the hypoxia of the tumor microenvironment, achieving steadily synergistic anti-tumor effect. This study verified the glucose oxidase-like properties of Ru NPs for the first time, and the strategy enhanced the synergistic anti-tumor effects by CDT and starvation therapy, which provided a basis for further exploration of Ru nanozyme activity and application on antitumor.