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Study On Building, Mechanism And Application Of Glucose Biosensor

Posted on:2012-02-05Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y Y WeiFull Text:PDF
GTID:1118330335466026Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
Glucose is a simple sugar (monosaccharide) and an important carbohydrate in biology. The measurement of glucose has played an important role in clinical chemistry, biochemistry and food analysis. The analysis and detection of glucose is the focus of research. With the improvement of people's living standards and increase of the elderly population, the incidence of diabetes is rising and becomes the third dangerous disease which is only less than cardiovascular disease and cancer. The diagnosis and treatment of diabetes has become the major issue in medical. Therefore, how to detect blood sugar rapid, accurate and convenient, and then monitor and treat the diabetes effectively is becoming more and more important. Many important research of the glucose test has been made already.Amperometric enzyme electrodes, based on GOx, have played a leading role for the determination of glucose due to their high sensitivity, repeatability and simple operation. Since the development of the first glucose biosensor, improvement of the response performance of enzyme electrodes has been the main focus of biosensor research.Nanomaterials are defined as the materials with domain ranges between 1 and 100 nm at least in one dimension, or materials that be composed of nanoscale units. Nanomaterials have many properties such as quantum size effect, surface effect, small size effect, quantum tunneling effect, dielectric confinement effect and so on. The unique properties of nanomaterials as optical, electrical, magnetic, catalytic and others attract the great concern of condensed matter physicist, chemist and materials scientists. The nanomaterials have in-depth research and broad application prospect in solar battery, catalytic, electronic information technology and biosensor, etc. The sensitivity, detection limit and the range of response have been improved with the special properties of nanomaterials. Nanomaterials have brought new opportunities and created a broader space for biosensors. In this thesis, GOx is immobilized with Click Reaction, poly (amidoamine) dendrimers (PAMAM) and polydopamine film, leaf-like CuO nanoparticles, ZnO/Au nanocomposites and WO3 nanoparticles have been synthesized with hydrothermal method to enhance the sensitivity and detaction limit of glucose biosensor. The morphology and composition of synthesized nanomaterials were characterized by the means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), electron diffraction spectrometry (EDS) and UV-visible spectrophotometry. The determination and analysis of glucose were carried out by cyclic voltammetry (CV), electrochemical impedance spectrum (EIS) and amperometric detection. In this paper, the stability, sensitivity and detection limit of the glucose biosensor have been enhanced greatly. Based on direct electron transfer between the enzyme and electrode, the signals of glucose biosensor can be accessed simply and directly. The direct electron transfer between GOx and nanomaterials was investigated, and the mechanism of the glucose detection by GCE/WOs/GOx/Nafion electrode was investigated. Based on this, manufacture of noninvasive blood glucose meter was constructed and developed. Totally, there are eight chapters in this paper.Chapter 1 PrefaceThis chapter has five parts, which are the present glucose detection techniques, development of the glucose biosensor, immobilization of enzyme on the surface of electrode, synthesis of nanomaterials and its application in glucose biosensor. Then the study and progress of glucose detection, the sort and development of glucose biosensor, the latest research of enzyme immobilization have been briefly introduced. Lastly the sort, properties and synthesis of nanomaterials has been introduced, the hydrothermal method of synthesis nanomaterials and its application has been discussed particularly.Chapter 2 Biofunctionalization of gold nanoparticles with glucose oxidase via click reaction and its application for biosensingA facile and efficient method for the preparation of functional glucose oxidase and gold nanoparticles (GOx-AuNPs) conjugates via "click reaction" has been developed. In a copper (Ⅰ)-catalyzed 1,2,3-triazole cycloaddition, an acetylene-functionalized GOx has been attached to azide-functionalized water soluble AuNPs and which retained 80%of the native enzymatic activity. The products have been used in glucose biosensor and the fabricated amperometric glucose biosensor exhibited a high and reproducible sensitivity, short response time, low detection limit, wide linear range and good stability. It is estimated that this fabrication method of enzyme can be promising candidate for variable biosensors.Chapter 3 Ultrasound-radiated synthesis of PAMAM-Au nanocomposites and its applicationon glucose biosensorHybrid nanocomposites of carboxyl-terminated generation 4 (G 4) poly (amidoamine) dendrimers (PAMAM) with gold nanoparticles (AuNPs) encapsulated inside them were synthesized under ultrasound irradiation. The obtained nanocomposites were used to fabricate highly sensitive amperometric glucose biosensor which exhibited a high and reproducible sensitivity of 2.9 mA/mM/cm2, response time less than 5 s, linear dynamic range from 0.1 to 15.8 uM, correlation coefficient of R2= 0.9988, and limit of detection (LOD), based on S/N ratio (S/N= 3) of 0.05μM. A value of 2.7 mM for the apparent Michaelis-Menten constant Km2pp was obtained. The high sensitivity, wider linear range, good reproducibility and stability make this biosensor a promising candidate for portable amperometric glucose biosensor.Chapter 4 Glucose Biosensor Based on the Fabrication of GlucoseOxidase in the Bio-Inspired Polydopamine-GoldNanopartiele Composite FilmA highly efficient enzyme immobilization method has been developed for electrochemical biosensors using polydopamine films with gold nanoparticles (AuNPs) embedded. This simple enzyme fabrication method can be performed in very mild conditions and stored in a long time with high bioactivity. The fabricated amperometric glucose biosensor exhibited a high and reproducible sensitivity, wide linear dynamic range and low limit of detection (LOD) (0.1μM). A low value of 1.5 mM for the apparent Michaelis-Menten constant KMapp was obtained. The high sensitivity, wide linear range, good reproducibility and stability make this biosensor a promising candidate for portable amperometric glucose biosensor.Chapter 5 Facile synthesis of leaf-like CuO nanoparticles and their application on glucose biosensorAn efficient amperometric biosensor based on well-crystallized leaf-like CuO nanoparticles for detecting glucose has been proposed. The leaf-like CuO nanoparticles, synthesized by a simple one-step hydrothermal method, were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) for the morphology study. Under the optimal condition, the electrochemical behaviour of the leaf-like CuO nanoparticles modified electrode for detection of glucose exhibited high sensitivity of 246 mA/mM/cm2, short response time (within 5 s), linear dynamic range from 1.0 to 170 mM (R2=0.9995), and low limit of detection (LOD) (S/N=3) of 0.91μM. The high sensitivity, good reproducibility, stability, and fast amperometric sensing towards oxidation of glucose, make this biosensor promising for future application.Chapter 6 ZnO nanorods/Au hybrid nanocomposites for glucose biosensorZnO nanorods/Au hybrid nanocomposites (ZnO/Au) with Au nanocrystals growing on the surface of ZnO nanorods were synthesized via a simple and facile hydrothermal route. The prepared ZnO/Au nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) for the morphology study. The composites had a good electron transferring and biocompatibility. The glucose biosensor was fabricated by entrapping glucose oxidase (GOx) in this composite matrix using cross-linking method with glutaraldehyde and Nafion solutions. The proposed biosensor responded to glucose linearly over concentration range of 0.1-33.0μM (R2= 0.9956), and the detection limit was 10 nM (S/N= 3) at an operating potential of+0.55 V in pH 7.4 phosphate buffered solution (PBS). The biosensor exhibited a high and reproducible sensitivity, short response time (within 5 s), good storage stability and high affinity to GOx (Kmapp=0.41 mM). The effects of electroactive interferents at the testing conditions can be negligible which showed a good selectivity of the biosensor. It is estimated that this ZnO/Au is an attractive material for the fabrication of efficient amperometric biosensors.Chapter 7 The electrocatalysis of glucose by GCE/WO3/GOx/Nafion electrodeWO3 was synthesized via a simple and facile hydrothermal route. The prepared WO3 nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and ultraviolet-visible spectrophotometry (UV-vis) for the morphology study. In saturated buffer solutions, the cyclic voltammetry of GOx intrapped in WO3 showed a pair of well-behaved redox peaks that are assigned to the redox reaction of GOx, confirming the effective immobilization of GOx on the composite film. The electron transfer rate constant was estimated to be 3.6 s-1, which indicated WO3 nanomaterials are good electron promoter. The immobilized GOx in WO3 nanomaterials retained its bioactivity. The fabricated amperometric glucose biosensor exhibited a high and reproducible sensitivity, wide linear dynamic range, low limit of detection, good stability and anti-interference ability. These results indicated that WO3 nanomaterials are good candidate material for construction of the third-generation enzyme biosensors based on the direct electrochemistry of immobilized enzymes.Chapter8 Manfacture of noninvasive blood glucose meterA noninvasive blood glucose meter was developed by means of electrochemical theory of glucose biosensor, combined with the special properties of nanomaterials. The developed instrument has miniaturized design, easy to take suggesting that it is a very promising analytical instrument for application, and the greatest characteristic of this instrument is it can achieve the blood sugar noninvasive testing.
Keywords/Search Tags:Glucose oxidase, Glucose detection, Glucose biosensor, Nanomaterials, Electrochemical analysis, Noninvasive blood glucose Meter
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