Construction Of Electrochemical And Colorimetric Sensors Based On New Transition Metal Nanomaterials

Because of the advantages of low cost,convenient operation,high sensitivity and fast detection efficiency,biosensors have important application prospects in medical diagnosis,environmental pollution monitoring,food safety detection and other fields.Nanomaterials are important units in the construction of biosensors,and their properties are the key factors affecting the performance of biosensors.In this work,a series of transition metal-based nanomaterials and nanocomposites were prepared,meanwhile a variety of electrochemical and colorimetric biosensors were successfully constructed through the functional treatment steps,and the analytes of thrombin,lead ion(Pb²⁺)and organophosphorus pesticides were detected.The specific research contents include three parts:（1）PB-Au@Mo S₂ composite material was successfully prepared by loading gold nanoparticles and Prussian blue nanoparticles on the flower-like molybdenum disulfide.Using the composite material for electrode modification,a signal attenuated electrochemical sensor for thrombin detection was constructed.Through the optimization of experimental conditions,the sensor has high sensitivity for thrombin detection,the linear range is 0.01 p M～30n M,and the detection limit can be as low as 1 f M.At the same time,the content of thrombin in human serum can be determined.（2）Gold nanoparticles have strong peroxidase-mimicking enzyme activity,and the activity will change with different dispersion states of the nanoparticles.Based on this,a signal-enhanced colorimetric sensor was developed to detect Pb²⁺.Gold nanoparticles were modified by DNAzyme and could specifically recognize Pb²⁺.The sensor can detect Pb²⁺in two linear ranges:25 p M～2.5μM and 2.5μM～250μM,with detection limit as low as 10 p M.（3）Pt Cu₃ polyhedral nanoparticles were prepared and their morphology was characterized.It was found that Pt Cu₃nanoparticles with concave surface had better peroxidase simulated activity than Pt nanoparticles and Cu nanoparticles of the same size.UV-Vis of acetylcholinesterase and organophosphorus pesticides could be realized by using the nanoparticles instead of horseradish peroxidase.The concentration of hydrogen peroxide could be visually detected by colorimetric method when Pt Cu₃ is stored on the test paper.