Studies On The Application Of Graphene Modified Electrodes In Electrochemical Biosensors

In this thesis, we are devoted to graphene applications in biosensors for basic research. Consist of three main parts: Electrocatalysis of hroseradish peroxidase immobilized on graphene electrodes; based on electropolymerization of glucose oxidase on the platinum nanoparticles/graphene composite modified carbon electrode; compared with the electrochemical electrocatalytic oxidation of NADH for MB functionalized graphene electrodes and graphite oxides electrodes.(1) A biosensor was proposed for selective and sensitive detection of hydrogen peroxide. This mediatorless biosensor was made by immobilization of horseradish peroxidase (HRP) in an electropolymerized pyrrole (PPy) film on a graphene coated electrode. We aslo studied the catalytic activity of hydrogen peroxide on the C/RG/HRP electrode. In addition, we discuss the analytical parameters of the the biosensor.(2) We have prepared the new glucose biosensor for the graphene as the catalyst carrier. Glucose oxidase (GOD) loaded on the platinum nanoparticles/graphene (Pt/RG) composite modified carbon electrode. The catalytic properties of Pt/RG/GCE electrode were studied. The Pt/RG/GCE electrode exhibited excellent electrocatalytic activity. In addition, we studied the analytical parameters of the glucose biosensor.(3) We compared the graphene (RG) and graphite oxide (GO) modified electrode for catalytic NADH oxidation. We also studied the catalytic activity of MB loaded on RG (MB/RG) in comparison with that of MB on graphite oxide (MB/GO). The catalytic properties of MB/RG/GCE electrode is better. Based on the results, Meldola's blue (MB) functionalized graphene (RG) nanocomposite film (MB/RG) electrode was prepared by adsorbing MB on the surface of a graphene modified glassy carbon electrode (RG/GCE). The analytical parameters of the NADH sensor were also discussed and the main analytical data were also compared with those obtained with the MB/GO/GCE.