Mimetic Enzyme Properties Of Cu_2-xSe Nanoparticles And Their Analytical Applications

Natural enzymes are a class of catalytic activity of a protein which has high catalytic efficiency,strong specificity,mild reaction conditions and so on.However,the natural enzyme is susceptible to a variety of physical and chemical factors inactivated,so can not use the enzyme in vivo to replace the industrial catalyst and some aspects of the analysis and detection.Mimetic enzymes are artificially synthesized with a class of catalysts with enzymatic properties.The study of mimetic enzymes is mainly aimed at solving the above shortcomings of enzymes.Due to the rapid development of nanotechnology,nanomaterials because of its size and makes related properties are widely used in catalysis research.Historically,the catalytic enzymatic properties of nanoparticles have not been well known.In recent years,the researchers have found that Cu_2-xSe nanoparticles are a kind of chalcogenide copper nanocomposites with photocatalytic properties,electrocatalytic properties and mimetic enzyme properties and are widely used in analytical testing and other fields.Not only that,Cu_2-xSe nanoparticles also have a special crystal structure,which can greatly enhance its catalytic capacity.The ability to catalyze in different systems is also different.Such as catalysis in tetramethylbenzidine-hydrogen peroxide?TMB-H₂O₂?,terephthalic acid-hydrogen peroxide?THA-H₂O₂?,and luminol-hydrogen peroxide?luminol-H₂O₂?.Ability is different.It can be known from the literature that Cu_2-xSe nanoparticles have intrinsic catalytic properties and can produce reactive oxygen free radical?ROS?related to catalytic activity during the catalytic process.Interestingly,the catalytic mechanism of Cu_2-xSe nanoparticles in acidic and alkaline media is different.In the acidic medium,Cu_2-xSe nanoparticles can catalyze the decomposition of H₂O₂ into reactive oxygen free radicals,but not in the alkaline medium H₂O₂ is decomposed into reactive oxygen free radicals but H₂O.It can be seen that the catalytic performance of Cu_2-xSe nanoparticles is worth studying.For a deeper understanding of the catalytic activity of the Cu_2-xSe nanomaterial mimic enzyme,we first studied the catalytic properties of the Cu_2-xSe nanomaterial mimicking enzyme,such as the influence of external factors,catalytic kinetics,etc.,and detailed understanding of its catalytic properties;Then by studying the participation of free radicals in the catalytic process,and then clarifying the catalytic process of Cu_2-xSe nanomaterials mimicking enzymes,the corresponding catalytic mechanism was proposed.In this paper,Cu_2-xSe nanomaterials were used as the research object,and the nanomaterial mimetic enzyme system was constructed.The catalytic properties and mechanism of the peroxidase were studied and applied to the analysis of melamine and glucose.1.It has been found that Cu_2-xSe nanoparticles have strong peroxidase mimetic enzyme catalytic activity.The catalytic ability of Cu_2-xSe nanoparticles was studied in detail.The results showed that the catalytic ability was dependent on the concentration,pH,time and temperature of Cu_2-xSe and the concentration of TMB and H₂O₂.The catalytic kinetics of the peroxide-mimetic enzyme was studied.Although the binding ability of Cu_2-xSe nanoparticles to the substrate 3,3',5,5'-tetramethylbenzidine was lower than that of horseradish peroxidase,However,Cu_2-xSe and melamine after the formation of aggregates,its catalytic capacity will be greater than the individual Cu_2-xSe nanoparticles.The catalytic mechanism of Cu_2-xSe nanoparticles was studied by colorimetric method and UV-Vis absorption method.The catalytic ability of Cu_2-xSe nanoparticles to simulate peroxidase was related to the active oxygen free radicals.Based on Cu_2-xSe nanoparticles to simulate peroxidase,a method for the detection of melamine was established.The linear range is 4.7 nM to 29.7?m.The detection limit is1.2 nM.2.Cu_2-xSe-Bi₂MoO₆ complex was synthesized by hydrothermal method for the first time,and it was found that it had mimetic enzyme catalytic properties.The morphology and composition of the films were characterized by scanning electron microscopy?SEM?,transmission electron microscopy?TEM?and X-ray photoelectron spectroscopy?XPS?.Finally,the Cu_2-xSe-Bi₂MoO₆ complex was used for indirect determination of glucose,the linear range was 0.025-20 mM,and the detection limit was 3?M.Therefore,we carried out a series of experiments to study the catalytic properties of Cu_2-xSe nanoparticles.According to its catalytic kinetic process,the catalytic process of Cu_2-xSe nanoparticles belongs to the typical Michaelis Menten kinetic process.Its catalytic activity is closely related to the active oxygen free radical and will be affected by external factors.