Studies Of Hydrogen Peroxide And Glucose Biosensors Fabricated Using Nanomaterials

Nanomaterials unique physical and chemical properties in many fields, will cause change. Among them, Nanomaterials as a kind of novel biological sensing medium caused the researchers interested in biological sensors. Nanomaterials pertaining to the development of the electrochemical biosensor is the interdiscipline subject of the nanotechnology and life science. Biological sensors has a high sensitivity and selective, simple operation, test fast, cheap, and has been widely used in the environment, clinical, food et al. The application of nanomaterials will be further improved biosensor performance, meanwhile, can promote electrode with biological molecules activity center, and the direct electron transfer can keep the activity of biological molecules. Therefore, Nanomaterials used to build up biosensor, be helpful for innovation in establishing some new ideas, is a promising field.Part 1 Study on hydrogen peroxide biosensor based on the synergy between zirconiu dioxide and carbon nanotubes modified glass carbon electrodeCarbon nanotubes can promote enzyme direct electron transfer and nanometer materials with other between the characteristics of synergistic, make its system biological sensors have better performance. First, zirconium dioxide (ZrO2) were solubilized in the aqueous solution of a biopolymer chitosan (CS) and the mutlicarbon nanotubes (MWNT) was introduced into the ZrO2-CS solution to get a MWNT-ZrO2-CS composite. Then the MWNT-ZrCb-CS composite was immobilized onto the surface of the glass carbon electrode (GCE). Subquently, a stable nano-Au film was electrodeposited on the MWNT-ZrO2-CS modified electrode by applying an constant potential. Finally, horseradish peroxidase (HRP) was immobilized onto the nano-Au layer to obtain the HRP/nano-Au/MWNT-ZrO2CS/GCE electrode. The results showed that the synergistic effect between MWNT and ZrO2 can illuminate well reduction ability to hydrogen peroxide with high sensitivity and fastresponse time. The resulting biosensor displayed a rapid response to H2O:and the linear range of the biosensor was from 7.80×10-6 to 9.26×10-3 mol/L with the detection limit of 2.8×10-6 mol/L mol/L (S/N=3). In addition, the biosensor showed fast response, high sensitivity. good stability and reproducibility.Part 2 A novel directly catalyzing hydrogen peroxide sensor based on Cu2O-SiO2 nanocompositesDue to the enzyme based-sensor existing some shortcomings, such as poor stability and reproducibility. as well as low sensitivity. To minimize or eliminate these limitations. chemically modified electrodes which needn't any enzyme are gaining.an increasing attention and will become a trend to detect HnO2. A successful system of hydrogen peroxide without the enzyme sensor, namely directly catalytic hydrogen peroxide sensor, was developed by immobilizing novel Cu2O-SiO2 nanocomposites, synthesized via a solution-phase method, on the surface of electrode. The performances of this sensor that the Cu2O-SiO2 exhibit electrocatalytic bihavior to H2O2 were observed by cyclic voltammetry (CV) method and chronoamperometry. The results confirmed that the sensor was simple to prepare, low-cost, fast response, good stability and linear response in the range of 3.5×10-7～7.5×10-3 mol/L with the lowest detection limit of 1.2×10-7mol/L(S/N=3).Part 3 Glucose biosensor based on the synergy between carbon nano-tubes and titanium oxideRecent research shows that the introduction of electronic medium body can accelerate electronic transfer rate, but the electronic medium body existing problems such as leakage and rich product, which affects the stability of electrode. Use nanoparticles synergies between, combining the electrodeposition and adsorption advantages, developed a new kind of no electronic media body of glucose sensor. The modified process and the electrochemical characteristics of the resuiting biosensor were characterized by cyclic voltammetry (CV). electrochemical impedance spectroscopy (EIS), and chrpnoamperometry. Under the optimal conditions, a linear dependence of the catalytic current upon glucose concentration was obtained in the range of 3.0×10-6 to 1.45×10-3 mol/L with a detection limit of 8.5×10-1 mol/L(S/N=3). In addition, the biosensor showed high sensitivity, good stability and excellent selectivity.