Study On Nano-Materials And Its Application To Enhance The Amperometric Enzyme Electrode

Glucose biosensor is widely used for the detection of glucose since its specific character: convenient application, rapid response, high sensitivity and selectivity. Some techniques have been taken to improve the response properties of biosensor. One way is to choose the proper material and method for the immobilization of enzyme to improve the stability and reactivity. Another way is to introduce the electron transfer mediator in the immobilization membrane to improve the response current and selectivity of the biosensor.A novel technique for enzyme immobilization by electrospinning poly(vinyl alcohol) (PVA) and glucose oxidase (GOD) on the surface of the Au electrode for amperometric biosensor are presented. The immobilized GOD remained active inside the electrospun PVA fibrous membranes. The membranes are promising candidates for immobilization of enzymes because of their high specific surface area and porous structure. The IR spectrum, the UV-Vis spectrum and the SEM of the membranes showed that the enzyme had been immobilized inside the PVA membranes.Chronoamperometric measurement demonstrated that electrospun fibrous enzymatic electrode exhibited a rapid response and a higher response current to glucose in the normal and diabetic level. The linear response range and upper detection limit of the sensor is satisfying. Au nanoparticles were introduced inside the electrospun films as the electron medium to enhance the catalytic activity of the sensor.A sensitive and selective amperometric glucose biosensor based on Ag microparticles dispersed in nano-fibrous polyaniline (PANI) was investigated. Nano-fibrous PANI is synthesized on Au electrode by a new technique termed pulse galvanostatic method (PGM). Due to its large specific surface area, good conductivity, high reaction ability, and many microgaps existing between the fibers, polymer with this morphology has potential application in electrocatalyze , and GOD was co-immobilized in Ag-modified nano-fibrous PANI to constructing multi-layered biosensors. The performances of the multi-layered glucose biosensor, i.e. linear range, sensitivity, selectivity, response time, stability and reproducibility, are all improved.Metal nanoparticles were in situ formed by reduction of corresponding metal salts with sodium citrate in the presence of chitosan. And chitosan molecules adsorbing onto the surface of as-prepared metal nanoparticles formed the corresponding...