Preparation Of Wire-based Electronic-mediated GlucoseOxidase Biosensor

Diabetes is a worldwide public health problem, the cause of the disease is due to the disorder of insulin secretion in patients with metabolic disorder caused by the body, causing hyperglycemia and accurate determination of glucose in the blood is an important means of controlling the disease. Under physiological glucose concentrations in human normal conditions of 80-120 mg / dL(4.4-6.6 mM), glucose concentration in diabetic patients is usually too high or too small for the normal physiological range of glucose. Complications caused by diabetes are many, including a higher risk of heart disease, kidney failure or blindness. Thus, in the prevention and treatment of diabetes, regular blood glucose testing and monitoring are essential tools.Based on the current enzyme electrode of glucose oxidase, have played an important role in the move to simple easy-to-use blood sugar testing. At the same time, in terms of continuous monitoring of blood sugar, the same electrode will play an important role. Glucose oxidase(GOx) is a homodimeric enzyme in which the redox center, flavin adenine dinucleotide(FAD) is deeply embedded within the protein shell, making it unable to communicate directly with the electrode surface. Therefore, the challenges faced by the development of electrochemical glucose biosensor is the realization of glucose oxidase and the direct electron transfer between the electrode surface. So far, it has been reported about the direct electron transfer of glucose oxidase was mainly using nanometer materials such as gold nanoparticles, carbon nanotubes, graphene and polymer film, as well as the specific chemical reagent as electronic wire, realize direct electron transfer of enzyme activity center and the electrode surface. However, glucose oxidase biosensor prepared as described above using the enzyme remains easy to deletion, poor storage stability and repetition stability, susceptible to external interference and other disadvantages. This article aims to select efficient electrode modified material, the use of efficient material modification modified electrode preparation glucose oxidase biosensor performance, high sensitivity of the glucose oxidase biosensor, and to explore the different modified electrode material for glucose oxidase enzyme Learn affect the nature and structure.The main contents are as follows:1.The use of DMF dispersion MWCNTS, the dispersion modified glassy carbon electrode surface formed nanocomposite film to the composite film as a glassy carbon electrode modified material for immobilization of glucose oxidase. The structure of the special nature of multi-walled carbon nanotubes not only keep the activity of glucose oxidase and promote direct electron transfer of enzyme and the electrode surface. Using glutaraldehyde as crosslinking agent, DHB as molecular wires on the nanocomposite layer immobilization of glucose oxidase(GOx), to build a new glucose sensor. Good preparation of glucose oxidase sensors to detect glucose showed good performance, the linear range of 0.1~1.2 mmol/L, signal to noise ratio S/N=3, the detection limit of 0.2mmol/L, with high sensitivity and good reproducibility.2. Successfully constructed a glucose oxidase enzyme electrode based on the 3-aminopropyl triethoxysilane(APTES) as molecular wires, fixed with glutaraldehyde as the cross-linking agent. APTES commonly used as surface modifying agent or dispersing agent involved in the reaction, during the reaction, glutaraldehyde with glucose oxidase form reticular structure, in the form of covalent bonding have played an important role in fixed glucose oxidase. At the same time,there is the schiff base reaction between the amino on the surface of APTES molecular and glutaraldehyde.On the one hand,it will ease the structural changes of the enzyme which caused by high concentration of glutaraldehyde, on the other hand,it plays the role of electronic wire, between the electrode and enzyme molecules formed a bridge, reacting to the electronic collection and transfer to the surface of electrode, implements the enzyme active center and direct electron transfer between the electrode. The results showed that the glassy carbon electrode(GCE) modified with 3-aminopropyl triethoxysilane / glutaraldehyde / glucose oxidase mixture can be well maintained glucose oxidase activity, and significantly contributed to its electrochemical behavior. By the time the current counting method, in 0.01 mol / L phosphate buffered saline(PBS), the detected current and the glucose enzyme electrode catalyst concentration in the 1.0 ~ 13.0 mmol?L range linear relationship. The linear regression equation is: y=-0.00343x+0.05061, Correlation coefficient is 0.99914, noise ratio S/N=3, the detection limit of 0.2mmol / L.Thus, the electrode has a lower detection limit, theoretically has reached the standard of testing blood sugar levels under normal physiological level.