Shell Gold Nanoparticles-based Electrochemical Sensor Research

Recently, the hollow gold nanoparticles have received increasing interests in the preparation of biosensors due to their properties. Hollow gold nanospheres (HGNs) have several advantages over the solid counterparts such as high specific surface, low density and cost. In addition, hollow gold nanospheres can promote the electronic transfer in the electrochemical reaction and have specific catalytic characteristics for some substances due to the surface with more functional corps.In this paper, we combined layer-by-layer self-assembly technique with nano technique as following two main aspects of ideas:(1) because hollow gold nanoparticles can promote electron transfer, we fabricate electrochemical biosensors using hollow gold nanoparticles to get larger current response and higher-selectivity, (2) because of its good biocompatibility hollow gold nanoparticles are favorable to immobilization of bioactive substances and can be used as carrier material immobilizing bioactive substances on the electrode surface. The main points of this thesis are summarized as follows:1 Preparation and characterization of hollow gold nanoparticlesUniform Spherical and homospherical hollow gold nanoparticles were prepared by AuCl3·H2O and Bu4PBr using KBH4 using a reduction method. The transmission electron microscopy and ultraviolet-visible spectroscopy were used to characterize them. In the process of electrode modification, hollow gold nanoparticles can be used to enhance response signal and promote electron transfer.2 novel Glucose biosensor based on GOD/HGNs/Chits/GCEA novel type of glucose biosensor was fabricated by immobilizing chitosan (Chits), hollow gold nanospheres (HGNs) and glucose oxidase (GOD) on the surface of glassy carbon electrode (GCE). The hollow gold nanoparticles(HGNs) were characterized by Violet spedtroscopy and Transpassion electron microscopy. The behavior of the glucose biosensor was investigated by circle voltammetry, impedance spectrum. The results indicated that there were excellent linear relation between the current and concentration of glucose from 3×10-6 to 7.4×10-5 mol/L, with a detedction limit of 1.6×10-6 mol/L (S/N=3). Moreover, the interferences influencing the proposed biosensor were researched in detail, and the biosensor possessed excellent selectivity and good stability.3 Voltammetric Determination of H2O2 Using the Modified Electrode PB/HGNs/Chits/GCEA novel type of hydrogen peroxide biosensor was fabricated by Chitosan (Chits), hollow gold nanospheres (HGNs), and the electrodeposition of Prussian blue (PB). The results indicated that two well-defined peaks occurred at 0.120V and 0.254V, respectively. The electrode showed excellent linearly for 8×10-7-5×10-6 mol/L H2O2 with a fitted linear equation of lp=0.583 c (H2O2)+3.085(R=0.9997). The detedction limit was 6×10-7 mol/L (S/N=3). The biosensor possessed excellent selectivity and good stability.4 Sensitive tyrosinase biosensor for the determination of atrazineA new tyrosinase sensor for the determination of atrazine was prepared. Its electrochemical behaviour was evaluated by cyclic voltammetry (CV). The biosensor can be used for the determination of atrazine in the range of 8.7×10-7 -8.2×10-5 mol/L with a detection limit of 5.4×10-7 mol/L. The linear regression equation is lp=-0.328 c(atrazine)+4.414 with a correlation coefficient of -0.9934.