Amperometric Immunosensor Based On Multi-wall Carbon Nanotube Modified Electrode

Electrochemical immunosensors, which combine the specificity of immuno-chemical systems with the advantages of electrochemical transducer, such as robustness, sensitivity and inexpensive instrumentation, have been the subject of continued research in recent years.Carbon nanotubes, consisting of cylindrical graphene sheets with nanometer diameter, combine in a unique way with high electrical conductivity, high chemical stability, and extremely high mechanical strength and modulus. The subtle electronic properties suggest that carbon nanotubes have the ability to promote electron-transfer reactions when used as an electrode material in electrochemical reactions and make them also very attractive for the task of electrochemical sensing. We combine the unique properties of carbon nanotube with immunosensors to develop a series of sensitive immunosenors.The major contents in this thesis are described as follows: Chapterl, IntroductionThe principle, catalogue, immobilization method of active biocomponents of electrochemical immunosensors were described. The applications of carbon nanotubes in electrochemistry were summarized and the purpose of this research work was presented.Chapter 2, Amperometric immunosensor incorporating multiwall carbon nanotubes and horseradish peroxidaseA simple and highly sensitive amperometric method for the determination of horseradish peroxidase has been developed at a glassy carbon electrode modified with multiwall carbon nanotubes (MWNT). It was found that the catalytic reduction currents of quinine generated in the reaction of hydroquinone with hydrogen peroxide in the presence of horseradish peroxidase (HRP) was greatly enhanced at MWNT modified electrode in 0.10 mol L~-1 phosphate buffer solution (pH 7.0). In the optimized solution of 0.050 mol L~-1 PBS (pH 7.0) containing 2.0 x 10~-3 mol L~-1 H2O2 and 1.5x10~-3 mol L~-1 HQ, the catalytic reduction currents on a MWNT-modified glassy carbon electrode at a applied potential of+0.030 V is linear over a range from 5.0x10~10 to...