Multienzyme-Mimicking Au@Cu2O with Complete Antioxidant Capacity for Reactive Oxygen Species Scavenging

Most enzyme catalysts are unable to achieve effective oxidation resistance because of the monotonous mimicking function or production of secondary reactive oxygen species (ROS). Herein, the Au@Cu2O heterostructure with multienzyme-like activities is deigned, which has significantly improved antioxidant capacity compared with pure Cu2O for the scavenging of highly cell-damaging secondary ROS, i.e.,center dot OH. Experiments and theoretical calculations show that the heterostructure exhibits a built-in electric field and lattice mismatch at the metal-semiconductor interface, which facilitate to generate abundant oxygen vacancies, redox couples, and surface electron deficiency. On the one hand, the presence of rich oxygen vacancies and redox couple can enhance the adsorption and activation of oxygen-containing ROS (including O2 center dot- and H2O2). On the other hand, the electron transfer between the electron-deficient Au@ Cu2O surface and electron donor would promote peroxide-like activity and avoid producing center dot OH. Importantly, endogenous center dot OH could be eliminated in both acidic and neutral conditions, which is no longer limited by the volatile physiological environment. Therefore, Au@Cu2O can simulate superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione peroxidase (GPx) to form a complete antioxidant system. The deigned nanoenzyme is explored in the real sample world such as A549 cells and zebrafish. This work provides theoretical and practical strategies for the construction of a complete antioxidant enzyme system.

Automated summary

In this study, an Au@Cu2O heterostructure with multienzyme-like activities is designed, which shows significantly improved antioxidant capacity compared to pure Cu2O. The heterostructure can scavenge highly cell-damaging secondary reactive oxygen species (ROS), namely center dot OH. The presence of oxygen vacancies, redox couples, and electron deficiency at the metal-semiconductor interface of the heterostructure enables enhanced adsorption and activation of ROS and avoids the production of center dot OH.