Study On New Glucose Biosensor Electrode For Maintaining Natural Structure Of Enzyme Protein

In the past few years, nanomaterials have been a pioneering subject in the field of biosensor researches. This thesis is based on three systems of different kinds of nanomaterials and carries out researches on the biocompatibilities to glucose oxdase (GOD) which is onto electrode surface and the electrochemistry properties of the glucose biosensors. The specific contents are as follows:1. Coat the phosphonic acid-functionalized silica nanoparticles (PFSi NPs) onto the surface of glassy carbon electrode (GCE) to obtain the glucose biosensor. The result shows PFSi NPs can essentially maintain the native conformation of GOD, while the direct electron transfer of GOD on (PFSi NPs)/GCE exhibited excellent electrocatalytic activity for the oxidation of glucose, which means the proposed biosensor modifying PFSi NPs functions well. Moreover, the biosensor is used for the assessment of the concentrations of glucose in many real samples (relative error< 3%).2. Use the chitosan-polypyrrole (CS-PPy) nanocomposites to modify the surface of electrodes to obtain glucose biosensor. PPy has a favorable electrical conductivity and CS provides a biocompatible micro-environment for GOD. In addition, the 3D space of CS-PPy nanocomposites provide a significant increase in the effectiveness of GOD loading on the electrode surface and allow the electroactive probe to easily diffuse and the vantage of electron transfer between GOD and electrodes, which means that the resulting biosensor shows good performances.3. Fabricate glucose biosensor based on layer-by-layer self-assembly (LBLSA) multilayer films with loping gold, which depends on the decoration of the surface of electrodes. According to the alternate electrostatic adsorption of the positively/negatively charged individual components, the research succeeds in immobilizing GOD, poly(allylamine hydrochloride) (PAH) and gold nanoparticles (AuNP) onto the ITO electrode and discovering the bioactivity of LBLSA multilayer films to GOD and the influences on the electrochemistry properties of the biosensor by the different layers of multilayer film. Among the resulting biosensors (ITO/APTES/AuNP/(PAH/AuNP)n-1/GOD), the biosensor, of which the layers (n=3) of multilayer films modified ITO electrode (ITO/APTES/AuNP/(PAH/AuNP)2/GOD), has the best effect and shows a excellent performance.In the application of enzyme biosensor, the maintenance of natural conformation of enzyme protein is the key to preserving its bioactivity and the acquirement of excellent electrochemistry properties. The 3 nanomaterial systems are all characterized by such good biocompatibilities, simple preparation methods and outstanding performances that they will be further studied and applied in the practical analyses in the future.