| Nanotechnology and biotechnology are two key technologies of the 21st century. Herein, nanobiosensing technology is one of the cutting edges and becomes an emerging area nowadays. Biosensors have developed to be a frontier and newly-interdisciplinary including chemistry, biology, medical science and electronics since the development of the first glucose biosensor in 1967. Due to its simplicity, high sensitivity and potential ability for real-time and on-site analysis, biosensors have been widely applied in various fields including clinical diagnosis, environment monitoring, food control and industrial process and so on.The main work of this paper is focus on one of the most active field where nanotechnique combines with electroanalytical chemistry, developing and fabrication novel modified electrodes based on nanomaterials (electrochemical sensors). The main points of this thesis are summarized as follows:1. A high-performance amperometric glucose biosensor was developed, based on immobilization of glucose oxidase on a copper nanoparticles/chitosan/carbon nanotube-modified glassy carbon electrode. The copper nanoparticles and carbon nanotube had a synergistic electrocatalytic effect toward the reduction of hydrogen peroxide in the matrix of biopolymer chitosan, which obtained abundant amino-groups facilitating for immobilize glucose oxidase via glutaraldehyde cross-linking for fabrication of a new glucose biosensor. The biosensor exhibited excellent sensitivity (the detection limit is down to 0.02 mM), fast response time (less than 4 s), wide linear range (from 0.05 mM to 12 mM), and perfect selection.2. A novel film of chitosan-gold nanoparticles was fabricated by a direct and facile electrochemical deposition method and its application in glucose biosensor was investigated. HAuCl4 solution was mixed with chitosan and electrochemically reduced to gold nanoparticles, which can be stabilized by chitosan and electrodeposited onto glassy carbon electrode surfaces along with the electrodeposition of chitosan. The main advantage of this biosensor was its simplicity of preparation. The biosensor has good potential stability and reproducibility. And it exhibited a wide linear response range of 20μM to 5 mM with a correlation coefficient of 0.9939 for the detection of glucose. The detection limit is down to 12μM. 3. A new amperometric glucose biosensor was constructed, based on the immobilization of glucose oxidase with cross-linking in the matrix of chitosan on a glassy carbon electrode, which was modified by layer-by-layer assembled carbon nanotube /chitosan /gold nanoparticles multilayer films. The assembling process of multilayer films was simple to operate. Owing to the good electrical conductivity, strong adsorption of carbon nanotube and the ability of improving electron transfer between analyte and electrode surface of gold nanoparticles, the glucose biosensor displayed a excellent catalytic property to glucose. The linear range was 6×10-6～5×10-3 M, with a detection limit of 3×10-6 M estimated at a signal-to-noise ratio of 3, fast response time (less than 6 s). Moreover, it exhibited good reproducibility and stability.4. An amperometric glucose biosensor based on electrostatic self-assembling glucose oxidase and carbon nanotube on a glassy carbon electrode was described. Glucose oxidase was immobilized on the negatively charged carbon nanotube surface by alternatively assembling a cationc polydiallydimethylammonium chloride. The detection limit of the biosensor was 15μM and the linear range was 25μM～8 mM.
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