Preparation Of Two New Types Peroxidase Mimetic Enzyme And Study The Catalytic Property

Natural enzymes are proteins that catalyze chemical reactions in organisms?in addition to some RNA molecules called ribozymes?,and have been successfully used in various fields.However,natural enzymes are easily inactivated and digested by proteases due to environmol/Lental changes.In addition,high cost and strict storage conditions also limit their application.Therefore,the development of stable enzyme mimics is very attractive.As a new research field of artificial enzymes,compared with natural enzymes,nanoenzymes have many advantages,such as low cost,easy mass production,good stability,long-term storage and size/composition dependence of activity.In addition,compared with other artificial enzymes,nanoenzymes also exhibit unique properties.Their size?shape,structure,composition?is related to catalytic activity.They have comprehensive?multiple?functional activities.Large specific surface area is conducive to further modification and biological binding.They are sensitive to external stimuli and have self-assembly ability.The main research work of this thesis is to prepare new nanomaterials or nanocomposites for peroxidase mimetics and colorimetric analysis.The main contents include:1.CuS nanowires were synthesized by hydrothermal method.Polydopamine thin films were formed on the surface of nanowires by self-assembly of dopamine under alkaline conditions.Au nanoparticles were prepared by in-situ growth on the surface of CuS-PDA using sodium acetate as reducing agent.CuS-PDA-Au nanocomposites with peroxidase activity were prepared.Based on the excellent peroxide mimetic enzyme activity of CuS-PDA-Au nanocomposites,a fast and convenient colorimetric method for the determination of glutathione?GSH?was developed.Under the optimum conditions,the linear range of GSH detection is 5×10^-71×10^-4 mol/L,and the detection limit is 0.42?mol/L.At the same time,the method was applied to the detection of GSH in serum by standard addition method,which showed a good recovery rate,and the recovery rate ranged from 95.49 to 108.10%.2.Using hydrazine hydrate as precipitating agent and N-butyl pyridinium bromide as templating agent,porous-hollow structure was obtained with a surface area of 1958 m².g^-1and an average pore diameter of 30 nm.The nanoparticles revealed high peroxidase-mimicking activity.It is found that BSA strongly improves the catalytic activity of the nanozyme,while Sn²⁺inhibits its activity.A colorimetric method for Sn²⁺detection was designed.The method works in the 0.5¹00?mol/L Sn²⁺concentration range and has a lower detection limit of 0.36?mol/L.At the same time,the method is applied to the detection of Sn²⁺in water samples by adding standard method,showing a good recovery rate,which ranges from 97.35%to 104.63%.