Atomically Dispersed Cu Nanozyme with Intensive Ascorbate Peroxidase Mimic Activity Capable of Alleviating ROS-Mediated Oxidation Damage

Ascorbate peroxidase (APX) as a crucial antioxidant enzyme has drawn attentions for its utilization in preventing cells from oxidative stress responses by efficiently scavenging H2O2 in plants. For eliminating the specific inactivation of natural APXs and regulating the catalytic activity, single-atom nanozymes are considered as promising classes of alternatives with similar active sites and maximal atomic utilization efficiency to natural APXs. Herein, graphitic carbon nitride (g-C3N4) anchored with isolated single copper atoms (Cu SAs/CN) is designed as an efficient nanozyme with intrinsic APX mimetic behavior. The engineered Cu SAs/CN exhibits comparable specific activity and kinetics to the natural APXs. Based on the density functional theory (DFT), Cu-N-4 moieties in the active center of Cu SAs/CN are determined to exert such favorable APX catalytic performance, in which the electron transfer between Cu and coordinated N atoms facilitates the activation and cleavage of the adsorbed H2O2 molecules and results in fast kinetics. The constructed Cu SAs/CN nanozyme with superior APX-like performance and high biocompatibility can be applied for effectively protecting the H2O2-treated cells against oxidative injury in vitro. These findings report the single-atom nanozymes as a successful paradigm for guiding nanozymes to implement APX mimetic performance for reactive oxygen species-related biotherapeutic.

Automated summary

This study presents a single-atom nanozyme Cu SAs/CN with APX-like behavior, showing comparable activity and kinetics to natural APXs. Through density functional theory, the Cu-N-4 moieties in the active center of Cu SAs/CN are determined to facilitate the activation and cleavage of H2O2 molecules, resulting in fast kinetics.