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Electrochemical Biosensor Based on Novel Nanomaterials

Author: WangSuiPing
Tutor: ShenGuoLi；YuRuQin
School: Hunan University
Course: Analytical Chemistry
Keywords: Electrochemical biosensor Template Seed Law Needle gold nanocluster Toluidine Blue Poly nanowires Hydroxyapatite nanowire arrays Cobalt hexacyanoferrate nanocomposite Platinum nanoparticle composites Coral -shaped gold nanoparticles
CLC: TB383.1
Type: PhD thesis
Year: 2009
Downloads: 637
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Abstract

Biosensor is a typical multidisciplinary product is to analyze the important areas of biotechnology, after 30 years of development, has become a matter of wide-ranging, multi-disciplinary and cross-intervention, full of innovation and dynamic field. Electrochemical biosensor research content is very rich, has been in a leading position in biosensors to obtain a large number of research results, and has been widely applied. The introduction of nano-technology, research and development of biological sensors to a more advanced stage, and in the performance greatly improved. Nanomaterials effect brought large surface area, good chemical stability and biocompatibility, high adsorption capacity and other characteristics can significantly improve the biological sensing element of the fixed and signal amplification. In this thesis, starting from the assembly of ordered nano system, using the template method and the Seed Law, building excellent new electrochemical biosensing interface, in order to improve the efficiency of biological molecules fixed, orderly orientation and maintain good biological activity, while providing good electron transfer. Biosensor developed simple preparation method has excellent performance, good reliability, the advantages of easy regeneration. Details are as follows: (1) the use of polycarbonate template steric hindrance and guiding role, directly on the glassy carbon electrode surface electrodeposition dimensionally ordered gold clusters; and human IgG as a model, the modified electrode used to build the sandwich immune electrochemical sensors. Electrodeposition of gold clusters provide a direct electron transfer protein molecules fixed and interfaces, without requiring any further modification and orderly adjustment. Scanning electron microscopy, cyclic voltammetry, electrochemical impedance method is used to study the modification of the interface properties. The prepared gold clusters with good stability, large surface area, biocompatibility and electron transfer good performance characteristics. Under the optimum conditions, the linear range of detection of human IgG was 1 ng mL-1 to 10μg mL-1, covering four orders of magnitude, a detection limit of 0.5 ng mL-1 (3 S / N). Calibration curve for the quadratic fitting curve (R2 = 0.9914). Immunosensor based on gold clusters with assembly method is simple, fast response, low detection limit, wide linear range, easy regeneration, reproducibility and good stability (Chapter 2). (2) the use of a polycarbonate template was first synthesized with the electric deposition average diameter of about 200 nm, a length of about 5μm polyethylene nanowire toluidine blue (PTBNWs). Scanning electron microscopy and transmission electron microscopy morphology characterization. Horseradish peroxidase (HRP) by in situ polymerization power, embedded in poly Nanowire toluidine blue (PTBNWs-HRP), hydrogen peroxide used in electrochemical biosensors. In PTBNWs-HRP modified glassy carbon electrode catalytic hydrogen peroxide reduction reaction, PTBNWs as an excellent redox electronic media between HRP and GC exhibit efficient electron transfer, the hydrogen peroxide sensor linear range 1μM to 28 mM, the linear correlation coefficient of 0.996, a detection limit of 1μM (3 S / N), the response time of less than 5 s (Chapter 3). (3) proposed a simple bio-friendly nanowire arrays based on hydroxyapatite (HANWA) preparing a biosensor. Electrochemical deposition method using a template prepared good biocompatibility, large surface area, with spatial orientation and a large number of adsorption sites HANWA, and apply cyanide biosensor construction. Arranged in an orderly array consists of nano-hydroxyapatite average diameter of 200 nm, a length of 1μm the vertical distribution of hydroxyapatite nano lines. Horseradish peroxidase (HRP) by means of chitosan (CHIT) immobilized on the surface of hydroxyapatite nanowire array, use of cyanide in the inhibition of the activity of HRP achieve this target the electrochemical determination. This organic / inorganic composite materials not only the enzyme biomolecule full contact with the substrate, while maintaining good fixing of the biological activity of the enzyme. Distribution of dense hydroxyapatite nanowire arrays having a large surface area and a large number of adsorption sites is excellent electrochemical biosensing interface. The HANWA / CHIT-HRP biosensor cyanide good spatial orientation, the detection sensitivity (detection limit of 0.6 ng mL-1), fast response, the advantages of rapid reproduction. This new device is expected to be applied to the analysis of environmental and food industry poison monitoring (Chapter 4). (4) for the first time applied to the seed law cobalt hexacyanoferrate nanoparticles (CoNPs) growth. With a particle size of 3.5 nm gold particles as seeds to multi-walled carbon nanotubes (MWCNTs) as a growth stents were successfully prepared CoNPs / CNTs modified glassy carbon electrode, the composite nanomaterials on the reduction of hydrogen peroxide has a synergistic effect. By Kim seeds, one-step synthesis CoNPs, no other coupling reagents in the case of modified glassy carbon electrode, modified method is simple, skillfully played the electrochemical properties of cobalt hexacyanoferrate. Immobilization of glucose oxidase, the glucose sensor for sensing interfaces. CoNPs kind of formation is small gold nanoparticles in the chemical deposition process. Seed gold cobalt cyanide bridged nanoparticles of iron and carbon nanotubes to form a nanocomposite clever. Spherical CoNPs relatively uniformly dispersed in the three-dimensional network structure of carbon nanotubes, the average particle size of 100 nm. In the absence of gold seed control experiments, cobalt hexacyanoferrate forming a continuous film, and its size is much larger than the nano level, the catalytic performance is also greatly reduced. The synthesizer / preparation / modification method is simple, fast, without pre-prepared cobalt hexacyanoferrate nanoparticles and time-consuming cross-linking process. Amount of seed was optimized, and the amount of carbon nanotubes growing time, the concentration of growth solution. Using a scanning electron microscope (SEM) and were characterized by electrochemical methods (Chapter 5). (5) propose a gold nanoparticles (AuNPseed) as seed, composite carbon nanotube modified electrode with platinum nanoparticles new method. First, the 3.5 nm gold nanoparticles was dropped in the modification of carbon nanotubes (CNT) of the electrode surface, and then the chlorine platinum electrodes immersed into a solution of ascorbic acid and growth in situ reduction of platinum nanoparticles (PtNP). Using electrodeposition method immobilization of glucose oxidase, the prepared AuNPseed / PtNP / CNT electrochemical glucose sensor with high sensitivity (4.49μA mM-1), fast response (2 s), low detection limit (0.5μM) and linear range Width (1μM-4 mM) and so on. The modified method for the design of other oxidase-based electrochemical sensor provides an idea (Chapter 6). (6) presents a highly sensitive detection of coral-shaped gold nanoparticles small biological molecules embedded methylene blue aptamers renewable electrochemical sensor. Gold electrode assembly hexanedithiol first, followed by assembly of gold nanoparticles (12 nm), and then into the growth solution (chlorine auric acid, cetyl ammonium bromide, and nicotinamide adenine dinucleotide) to 12 nm gold species grown for fixing capture probes. To adenosine as a model, by electrochemical impedance, ac voltammetry, scanning electrochemical microscopy, scanning electron microscopy and surface-enhanced Raman scattering and other means of modifying the interface properties. Describes the electrochemical signal generation due to adenosine and methylene blue competitive binding aptamer mechanism. The biosensor has the following advantages: high sensitivity, good selectivity, wide detection range (4 orders of magnitude), low detection limit (1 nM), for no special requirements aptamer structure, easy to spread, through the use of different adaptation detection of the corresponding sub-object (Chapter 7).

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