Preparation And Application Of Single Au Nanoelectrode

As the rapidly developmengt od the nanoelectrode, Electrodes with nano-scale size have shown tremendous advantages such as smaller RC constants, faster mass-transport rates, and lower influences from solution resistance. Due to their small size, nanoelectrodes are exhibiting their extensive applications in numerous areas, such as the study of electron transfer kinetics, detection of single molecules and single nanoparticles,high-resolution imaging in scanning electrochemical microscopy(SECM).In this work, we report the preparation and electrochemical responses of Au disk nanoelectrodes as small as 5 nm in radii and single Au nanowire electrode. The dissertation includes four chapters as follows:Chapter ?: A review is given on the introduction of nanoelectrode,biometal core@shell structure, DNA and research progress of electrochemical DNA biosensor.Chapter ?: We fabricated Au disk nanoelectrodes as small as 5 nm in radii by the improvement of laser-assisted pulling technique and the nanolelctrodes have been characterized using Field Emission Transmission Electron Microscopy(HR-TEM), Energy Dispersive X-RaySpectroscopy(EDX) and cyclic voltammetry(CV). The direct electrochemistry of ferritin molecules be used to research its appalication in eletrochemical biosensor.Chapter ?: A single Au nanowire electrode(Au-SPNEs) was fabricated through etching process from Au disk nanolelctrode, and then by underpotential deposition(UPD) redox replacement technique we fabricated nanowire electrode. We characterized the nanowire electrodes by Field Emission Transmission Electron Microscopy(HR-TEM), Energy Dispersive X-Ray Spectroscopy(EDX) and cyclic voltammetry(CV).These resulting electrode exhibits high elecrocatalytic activity towards the oxidation of methanol(CH3OH), the reduction of oxygen(O2) and hydrogen peroxide(H2O2).Chapter ? : We described a sensitive DNA biosensor base on Au nanowire electrode. Square wave voltammetry(SWV) was used to monitor the DNA hybridization event using methylene blue as an electrochemical indicator. These electrodes are highly compatible with the reagentless and reusable electrochemical sensing platform,This combined sensing approach can potentially be used for real-time detection of target analytes inside living cells.