Study On Nanomaterials Derived Enzyme Biosensors And Their Applications In Biological Samples

In the 21st century, life science will be the most active science. How to realize the in vivo and on-line determination of minim biological samples has importance role to the development of life science. At the same time, nanobiosensing technology is revealing its superiority in this way. However, nanotechnology-based biosensor not only have good effect on it, but also develop biosensor to be a high selectivity, rapid, handy and inexpensive instrument for real-time and on-site analysis. Up to now, the people have never stopped exploring arcanum of life, and always devote themselves to prevention, cure and salubrity. Biosensor has already been a fundamental technology in the medical examination, meanwhile nanotechnology-based medical biosensor will accelerate development of medico-science further.Certainly, nanotechnology provides infinite fancy space for development of biosensor, and there is many opportunities waiting for us. This dissertation focuses on 1)fabricating novel biosensors based on new nanomaterials and nanostructures, and integrated them with microdialysis, flow injection analysis, etc. 2)establishing the bases for application of them to biological and clinical diagnose, such as hydrogen peroxide, glucose, L-glutamate, lactate, hypoxanthine and uric acid. We are adhering to an organic combination of nanotechnology, biosensing technology and clinical researches. The details are given as follows:Chapter One: PrefaceA critical review with regard to the biosensor and nanotechnology is given, respectively. Then emphatically describe the application of nanotechnology into biosensors. Nanotechnology-based biosensors integrated with on-board electronics, sample handling and analysis will greatly enhance functionality, by providing devices that are small, portable, easy to use, low cost, disposable, and highly versatile diagnostic instruments. Portable instruments capable of analyzing multiple components are becoming available.Chapter Two: A Novel Glucose Biosensor Based on Palladium Nanoparticles and Its Application in Detection of Glucose Level in UrineBecause of the higher specific surface area of noble metal nanoparticles, they show higher catalytic activities than bulk metals. A novel glucose biosensor was constructed by electrodeposition of highly dispersed palladium(Pd) nanoparticles on a glassy carbon electrode (GCE). Atomic force microscopy (AFM) was applied to characterize its surface morphology. Electrodeposited Pd nanoparticles exhibited efficiently electrocatalytic oxidation for hydrogen peroxide(H2O2) with relatively high sensitivity and stability, which was studied by CV technique and Raman spectroscopy, respectively. The GC/Pd/GOD/Nafion system allowed a low working potential of +0.3V(vs.SCE). Its signal current was linearly related to the glucose concentration in the range of 1.0×10~-6~1.0×10~-4 mol.L-1 with a detection limit of 5.0×10~-7 mol-L-1.The sensor required no special pretreatment to suppress interference from urate and L-ascorbate. It was successfully use in detection of glucose level in human urine with high stability, sensitivity and anti-poisoning ability.Chapter Three: Amperometric Sensor Based on Ferrocene-Doped Silica Nanoparticles as Electron Transfer Mediator for the Determination of Glucose in Rat Brain Coupled to in Vivo MicrodialysisIn this section, microdialysis sampling was combined with enzymatic assay of glucose level in rat brain. A novel amperometric glucose biosensor based on ferrocene-doped silica (FcDS) nanoparticles conjugated with biopolymer chitosan (CHIT) membrane was developed. These uniform FcDS nanoparticles were prepared by a water-in-oil (W/O) microemulsion method, which were characterized by TEM and electrochemical technology. The nano silica surface exhibited high biocompability and the doped inside ferrocene maintained its high electron-transfer efficiency as a mediator. The glucose biosensor showed a detection limit of 5.0×10~-6 mol.L~-1 with the linear range from 1.0×10~-5 to 1.2×10~-2 mol.L-1.Coupled to microdialysis, it was used to determine the...