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Glucose Biosensor Based On Platinum Nanoparticles Decorated Composites

Posted on:2012-07-25Degree:MasterType:Thesis
Country:ChinaCandidate:J J LiFull Text:PDF
GTID:2178330335956724Subject:Inorganic Chemistry
Abstract/Summary:PDF Full Text Request
Recently, the rapid and accurate determination of glucose is of great importance from several points of view ranging from medical applications of blood glucose sensing to ecological approaches, such as in clinic medicine, environment measurement, food industry, and so forth. In order to improve the performance of glucose biosensor, Much effort has been focused on developing suitable techniques for precisely monitoring the glucose level in its biological environment. However, most of these methods are technically complicated or expensive in cost. Amperometric enzyme-based biosensors have attracted significant attention, owing to its high sensitivity and selectivity, low detection limit, compatibility for miniaturization, and ease of use.In 1967, the first glucose biosensor was developed which attracted more and more interest in enzyme biosensors. However, the key step in the development of glucose biosensor is the effective immobilization of glucose oxidase (GOD) on the electrode surface. This paper reports some enzyme glucose biosensors which combine the immobilization of GOD and several nanocomposites, and the main works and results are included as follows:1. Fabrication of a novel glucose biosensor based on Pt nanoparticles-decorated iron oxide-multiwall carbon nanotubes magnetic composite:A sensitive and selective amperometric glucose biosensor was obtained by using the electrodeposition of Pt nanoparticles on iron oxide-multiwall carbon nanotubes/chitosan (FeyOx-MWCNTs/CS) magnetic composite modified glassy carbon electrode (GCE) followed by the adsorption of GOD at the surface of the electrode. FeyOx-MWCNTs magnetic composite was characterized by transmission electron microscopy (TEM). The modified process and the electrochemical characteristics of the resulting biosensor were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry. The proposed biosensor exhibit excellent electrocatalytic activity and good response performance to glucose. The influence of various experimental conditions was examined for the determination of the optimum analytical performance. Under the optimal conditions, a linear dependence of the catalytic current upon glucose concentration was obtained in the range of 6.0×10-6 to 6.2×10-3 mol/L with a detection limit of 2.0×10-6 mol/L, and a response time of less than 8 s. The apparent Michaelis-Menten constant (KappM) was evaluated to be 9.0 mmol/L. Furthermore, the sensitivity for the determination of glucose at the GOD/Pt/FeyOx-MWCNTs/CS magnetic composite modified GCE is better than atcommonGOD/Pt/MWCNTs/CS and GOD/Pt-FeyOx/CS composite modified electrodes. The proposed biosensor has good anti-interferent ability and long-term storage stability after coating with Nafion, and it can be used for the determination of glucose in synthetic serum.2. Fabrication of a glucose biosensor based on immobilization glucose oxidase onto Pt hollow nanoparticle chainsA sensitive enzymed-based biosensor for glucose has been developed by immobilizing GOD onto Pt hollow nanoparticle chains (Pt HNPCs). Pt HNPCs have been synthesized at room temperature in a homogeneous solution employing cobalt metal nanoparticles as sacrificial templates. The characterization of Pt HNPCs has been done using UV-vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM). The performance of the biosensor has been studied using cyclic voltammetry (CV) and amperometry, and the results have been discussed. The electrocatalytic activity of the Pt HNPCs was evaluated using glucose as model molecules. Pt HNPCs are uniformly modified on the GCE, showing remarkably improved catalytic activities in electrochemical detection of hydrogen peroxide and glucose. The proposed biosensor exhibited excellent performances for glucose, a rapid response (< 3 s), a low detection limit (1.0×10-6 mol/L), a wide and useful linear range (3.0x10-6~6.6×10-3 mol/L) and high sensitivity as well as excellent stability and repeatability. Compared to the Nafion/GOD/Pt nanoparticles (PtNPs) based biosensor for glucose, the Nafion/GOD/Pt HNPCs modified electrode possessed high catalytic activity in the neutral phosphate buffer solution (PBS, pH 7.0), which was promising for the future development of other biosensors.3. Simple construction of an enzymatic glucose biosensor based on a nanocomposite film prepared in one step from iron oxide, gold nanoparticles, and chitosanThe one-step synthesis is reported of a nanofilm composed of iron oxide and gold nanoparticles in a chitosan matrix that can act as a novel matrix for the immobilization of GOD to fabricate a glucose biosensor. The use for the composite film strongly increased the effective electrode surface for loading of GOD. The size and shape of the iron oxide nanoparticles were examined by transmission electron micrograph. Direct electron transfer and electrocatalysis by GOD was investigated via cyclic voltammetry (CV) and chronoamperometry. Under optimized conditions, the biosensor has a response time of 6 s and a linear response in the range between 3x10-6 mol/L and 0.57x10-3 mol/L of glucose, with a detection limit of 1.2×10-6 mol/L at a signal-to-noise ratio of 3. This novel and disposable mediatorless glucose biosensor may form the basis for a future mass-produced glucose biosensor.
Keywords/Search Tags:Glucose biosensor, Glucose oxidase, Pt nanoparticles, Nanocomposite film, Chitosan
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