Study On The Synthesis And Catalytic Performance Of Two New Mimic Enzymes

Natural enzymes are essential substances for catalyzing biochemical reactions in living organisms.Most of them make up proteins(a few natural enzymes are RNA),and they have successfully divided various fields.However,due to the nature of the composition of natural enzymes,this makes it easy to cause degeneration and inactivation due to changes in environmental conditions.Simultaneously,the application of nature enzyme has been restricted,because it is in harsh storage circumstances and high-cost adstraction.Consequently,it has the significant value and prospects to developing enzyme mimics,that can subsite under harsh environmental circumstances.Therefore,under such demand conditions,nanozymes came into being.Compared with natural enzymes,nanozymes have advantages in many aspects,such as low cost,easy mass production,good stability,high durability,and long-term storage.Moreover,nanozymes also have the characteristics of controllable structure and morphology,which is beneficial for further modification or binding with biomolecules.The research work in this paper is mainly to synthesize new nanomaterials or nanocomposites for simulating oxidase and laccase,and for colorimetric and fluorescent analysis to detect small biological molecules and phenolic pollutants.The main contents are:1 Cu-Mn-O microcrystal were synthesized by the template method.Using micro-dumbbell-type MnCO₃ as a template,Cu was doped before synthesis of MnCO₃ and then calcined in air to prepare a micro-dumbbell-shaped structure of Cu-Mn-O Catalytic materials.Cu-Mn-O nanoenzyme has oxidase activity,which can oxidize the colorless substrate 3,3',5,5'-tetramethylbenzidine(TMB)to generate blue oxidation products,and then with carbon quantum dots(C-dots)binding.Based on the fluorescence internal filtering effect,the absorption wavelength of oxidized TMB overlaps with the emission of C-dots,resulting in a decrease in the fluorescence of C-dots,while dopamine has reducibility.As the result,the blue 3,3',5,5'-tetramethylbenzidine(TMB)oxidation product is discolored,and the fluorescent C-dots are restored,thereby achieving the purpose of detecting dopamine by colorimetry and fluorescence.The linear range is 0-75?mol/L by way of colorimetric method,and the detection limit is 0.5?mol/L,while the linear range of the fluorescence method is 0-100?mol/L,and the detection limit is 0.125?mol/Lol/L.This method is applied to the fetus through the method of standard recovery.The detection of dopamine in bovine serum obtained a good recovery rate,and the recovery rate ranged from 94%to 106.8%.2 The precursor of CoMoO₄ was synthesized by hydrothermal method,then calcined in air to further synthesize CoMoO₄,and then CoMoO₄-CoO/Cu Ni was synthesized in situ by the dipping method.CoMoO₄-CoO/Cu Ni nanoenzyme has laccase-like activity and can catalyze laccase substrates,such as phenol and 2,4-dichlorophenol.The oxidation products can react with the chromogenic reagent(4-AP)to produce colored substance and has UV/Vis absorbance at 510 nm.Therefore,CoMoO₄-CoO/Cu Ni nanoenzyme can be used to degrade phenolic pollutants and also used to detect epinephrine.Its detection linear range is 5-50?g/mL and the detection limit is 0.379?g/mL.Based on CoMoO₄-CoO/Cu Ni nanoenzyme to simulate laccase activity,combined with C-dots,based on the fluorescence internal filtration effect,oxidized phenol can form colored substances with 4-AP,and its absorption wavelength can overlap the emission of C-dots.As the result,the fluorescence of C-dots is reduced,and ascorbic acid has strong reducing ability,reduce the production of oxidized phenol and 4-AP,and decrease the absorbance,which makes the fluorescence of C-dots It rises with the increase of the ascorbic acid concentration,so that the colorimetric and fluorescent dual-signal detection of ascorbic acid is achieved.The linear range of ascorbic acid is 0-150?mol/L by the colorimetric method,and the detection limit is 11.9?mol/L.The linear range of the fluorescence method is 0-95?mol/L,and the detection limit is 1.6?mol/L.