Preparation Of Enzyme Mimics Based On Single-atom Catalytic System And Its Biomimetic Catalytic Applicatio

Enzymes have attracted extensive attention as natural biocatalysts with high catalytic activity and high selectivity,but the disadvantages of poor stability,easy deactivation,and valence greatly limit the large-scale application of enzymes in production.Therefore,there is a need to develop a stable and inexpensive alternative to enzymes—mimetic enzymes.Nanozymes stand out from a variety of mimic enzymes due to their low cost,high stability,tunable catalytic activity,easy mass production,and easy storage.However,the density of catalytic active sites of conventional nanozymes is low,so we combine single-atom catalytic technology with nanozymes to prepare single-atom nanozymes that maintain the advantages of nanozymes.Mimicking the catalytic active center structure of natural oxidoreductases,this study use a hydrothermal method to synthesize a zinc-MOF-coated metal phthalocyanine-mimetic enzyme precursor in one step,and obtaine a single-atom nano-enzyme product after high temperature calcination.By changing the type of metal phthalocyanine,the type of metal in the active center of the single-atom nanozyme can be adjusted;by changing the organic ligand of zinc-MOF,the coordination number of the metal in the active center of the single-atom nanozyme can be adjusted.In vitro activity test prove that iron-nitrogen coordinated single-atom mimetic enzymes have oxidase,peroxidase and catalase activities;copper-nitrogen coordinated and manganese-nitrogen coordinated single-atom mimetic enzymes have superoxide dismutase active.Among them,the catalytic activity of the single-atom mimetic enzyme with five nitrogen coordination is significantly higher than that of the single-atom mimetic enzyme with four nitrogen coordination.Imitating the catalytic active center structure of natural carbonic anhydrase,the ZIF-8 material is also synthesized by hydrothermal method,and the ZIF-8 single-atom mimetic enzyme is prepared by calcination at a slightly lower temperature.The carbonic anhydrase activity of this material is proved by calcium carbonate weighing method.Single-atom nanozymes have a higher density of active sites,which maximizes the atom utilization rate,thus greatly improving the catalytic activity of nanozymes and narrowing the gap between the catalytic activities of simulated enzymes and natural enzymes to a certain extent.Single-atom nanozymes are expected to replace natural enzymes to a certain extent and be further applied in industrial production and disease treatment.