Cascade Reaction System Integrating Single-Atom Nanozymes with Abundant Cu Sites for Enhanced Biosensing

Abstract

Single-atom nanozymes (SAzymes), as novel nanozymes with atomically dispersed active sites, are of great importance in the development of nanozymes for their high catalytic activities, the maximum utilization efficiency of metal atoms, and the simple model of active sites. Herein, the peroxidase-like SAzymes with high-concentration Cu sites on carbon nanosheets (Cu–N–C) were synthesized 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 oxidase, three-enzyme-based cascade reaction system was constructed for the colorimetric detection of acetylcholine and organophosphorus 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.

Tuning Atomically Dispersed Fe Sites in Metal–Organic Frameworks Boosts Peroxidase-Like Activity for Sensitive Biosensing

“…However, the catalytic activities of nanozymes are still much lower than those of natural enzymes [12][13][14]. Given the electronic and geometrical structures of enzymes are two key factors toward catalytic activities, accurately designing and tuning the electronic and geometrical structure of active sites at the atomic scale are important for the development of advanced nanozymes [15][16][17][18]. Specifically, the welldefined structures and coordination features of atomically dispersed active sites are of great significance for understanding the activity-structure relationships in nanozyme systems and achieving vivid mimicking of natural enzymes [19][20][21][22].…”

Advances in Single‐Atom Nanozymes Research†

“…Until now, the Fe, [ 25,28‐37 ] Co, [ 26‐27 ] Pt, [ 38 ] Zn, [ 39 ] Ru, [ 40 ] and Cu [41] ‐doped SAzymes have been developed based on the frameworks of carbon nanomaterials, [ 28‐36,39‐41 ] metal oxide nanomaterials [ 34 ] and metal sulfide nanomaterials. [ 27 ] By combining the high enzyme‐like catalytic activities and the well‐defined physicochemical properties, SAzymes make a very promising application prospect, especially in the fields of biomedicine.…”

“…synthesized a POD‐like SAzyme with high concentration of Cu sites doped on carbon nanosheets (Cu‐N‐C) through a salt‐template strategy (Figure 10a). [ 41 ] The densely distributed active Cu atoms (~5.1 wt%) on Cu‐N‐C SAzyme exhibited a remarkable POD‐like activity (Figure 10b). They designed a cascade reaction system by integrating Cu‐N‐C SAzyme with natural acetylcholinesterase (AChE) and choline oxidase (ChOx), and achieved the colorimetric detection of acetylcholine (ACh) (Figure 10c) and organophosphorus pesticides (OP) (Figure 10d).…”

“…(d) Schematic illustration of the ACC system for the OP detection. [ 41 ] Copyright 2020, American Chemical Society.…”

Single-Atom Nanozymes Linked Immunosorbent Assay for Sensitive Detection of A β 1-40: A Biomarker of Alzheimer’s Disease

“…Thereinto, SACs with enzyme-like characteristics are called single-atom nanozymes (SANs) and are regarded as ideal candidates to mimic the structure and catalytic activity of natural enzymes [ 7 – 10 ]. Nowadays, the SANs have found their extensive application as substitutions for natural enzymes in immunoassays [ 11 , 12 ], environmental treatment [ 13 ], biodetection, and biosensing [ 8 , 14 , 15 ] owing to their excellent performance, high stability, ease of large-scale production, and economical price.…”