Wu_2020_Anal.Chem__

Single-atom nanozymes (SAzymes), as novel nanozymes with atomically dispersed active sites, are of great importance in the de-velopment of nanozymes for their high catalytic activities, the maximum utilization efficiency of metal atoms, and the simple mod-el of active sites. Herein, the peroxidase-like SAzymes with high-concentration Cu sites on carbon nanosheets (Cu-N-C) were syn-thesized through a salt-template strategy. With the densely distributed active Cu atoms (~5.1 wt%), the Cu-N-C SAzymes exhibit remarkable activity to mimic natural peroxidase. Integrating Cu-N-C SAzymes with natural acetylcholinesterase and choline oxi-dase, three-enzyme-based cascade reaction system was constructed for the colorimetric detection of acetylcholine and organo-phosphorus pesticides. This work not only provides a strategy to synthesize SAzymes with abundant active sites but also gives some new insights for robust nanozyme biosensing systems.