Studies On The Enzyme-like Activities Of Oxygen-containing Copper And Manganese Nanomaterials

In recent years,more and more inorganic nanomaterials have been found to have enzyme-like activities,such as peroxidase activity,oxidase activity,glucose oxidase activity,and superoxide dismutase activity.Inorganic nanomaterials such as ferromagnetic nanoparticles,graphene oxide,noble metal nanoparticles are widely used in various fields such as medicine,chemical industry,and food processing due to their advantages of easy preparation and simple storage.In our study,several kinds of inorganic materials have been prepared and their enzyme-like acitivities,such as oxidase-like acitivity,cysteine oxidase-like activity,and cytochrome c oxidase-like acitivity,have been studied as stated below:Cu₂O,MnO₂,and Cu₂?OH?₃Cl materials were prepared by a simple method and characterized by transmission electron microscope?TEM?,scanning electron microscope?SEM?,high resolution transmission electron microscope?HRTEM?,X-ray powder diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,and electron paramagnetic resonance spectroscopy?EPR?.The enzyme-like properties of the as-prepared materials have been systematically studied on the catalytic activity,chemical stability and practical application as stated below:1.We prepared highly uniform cubic Cu₂O nanoparticles?NPs?with sizes of 50 nm,150 nm,and 500 nm,respectively.A biomacromolecule,cytochrome c?Cyt c?was employed as an enzyme substrate to study the cytochrome c oxidase?CcO?-like activity of the Cu₂O nanoparticles.It was found that Cu₂O NPs can effectively receive electrons from Cyt c and exhibit CcO activity,and their activity is related to the size of Cu₂O NPs,the concertration of O₂,and the pH of reaction solution.Based on the experimental results,it is concluded that the CcO-like activity of the Cu₂O NPs is closely related to the natural Cyt c-CcO system.2.Surface-porous MnO₂ microspheres?PS-MnO₂?and MnO₂-nanorods were prepared by a simple one-step hydrothermal method,and the PS-MnO₂ was found to have intrinsic oxidase activity in the absence of H₂O₂.In addition,based on the sulfite inhibition of the TMB-O₂-PS-MnO₂ system,a simple method for the detection of sulfites has been established.In addition,both kinds of MnO₂ exhibited CcO-like activity,which can catalyze the oxidation of Cyt c,convert it from reduced state to oxidized state under atmospheric conditions.Compared to PS-MnO₂,MnO₂ nanorods showed higher CcO-like activity.3.To further explore the enzyme-like activities and applications of inorganic materials,Cu₂?OH?₃Cl was synthesized by a simple method,and found that the as-prepared Cu₂?OH?₃Cl has cysteine oxidase catalytic activity.It can catalyze the oxidation of cysteine to cystine and convert O₂ to H₂O₂ and react with terephthalic acid to form terephthalate and produce fluorescence changes.The prepared Cu₂?OH?₃Cl can be used for the detection of cysteine,which is of great significance for applications in medicine,biochemical research,and cosmetics detection.