Dissertation > Excellent graduate degree dissertation topics show

Optical Biosensing Technology Based on Metal Nanomaterials for Detection of Enzyme Activity

Author: DuanMin
Tutor: YuRuQin
School: Hunan University
Course: Analytical Chemistry
Keywords: Optical Biosensing Technology Gold Nanoparticles Silver Nanoparticles Copper Nanoparticles Fluorescence Quenching Enzyme Activity Assay
CLC: Q55
Type: Master's thesis
Year: 2013
Downloads: 55
Quote: 0
Read: Download Dissertation

Abstract


In recent years, with the development of nanotechnology, various kinds ofnanomaterials including gold nanoparticles, quantum dots, magnetic nanoparticals andmetal nanoclusters have been studied. Because of their unique physical, chemical,mechanical, magnetic and optical properties, there has been great progress in thenanometerial based biosensors. Nanomaterial based biosensor research is amultidiscipline area integrating material science, molecular engineering, chemistry andbiotechnology. The nanomaterial based biosensors can markedly improve thesensitivity and specificity of biomolecule detection, and have great potential in manyresearch fields such as biomolecular recognition, pathogenic diagnosis andenvironment monitoring. Here, we developed a series of optical biosensors based onnovel nanomaterials such as Au nanopartical, silver nanocluster and coppernanocluster, to sensitively detect bacillus licheniformis protease, cholesterol andalkaline phosphatase （ALP）. The detailed methods are as follows:（1） A convenient and fast colorimetry method was developed to detect bacilluslicheniformis protease based on gold nanoparticals aggregation. A peptide with C-andN-terminal cysteine （Cys） and contained two D-leucines was designed as substrate forbacillus licheniformis protease assay. Cys strongly interacted with gold nanoparticleby Au-S bond, causing the aggregation of gold nanoparticles and the color of itssolution was changed from red to blue. Whereas, in the presence of target protease, theD-leucine residue selectively recognized the target protease and the peptide was cut off.The cleaved peptides were unable to induce gold nanoparticle aggregation; and as aresult there was no change in the color of the solution. A linear correlation between theratio of the absorbance at520and600nm （A520nm/A600nm） and the logarithm ofprotease concentration ranging from0.1to5μg/mL, with a detection limit of0.09μg/mL was obtained. Comparing to the traditional detection method, the presentanalytical strategy was simple, fast and demonstrated desirable selectivity.（2） A novel fluorescence sliver nanocluster synthesized by ssDNA template withtwo guanines at the3’. G-DNA-Ag NCs was developed to detect enzyme-basedsubstrate, cholesterol. In this assay, cholesterol was oxidized by dissolved oxygen （O2）in the presence of cholesterol oxidase to produce H2O2. Since H2O2could quench thefluorescence signal of the prepared G-DNA-Ag NCs, cholesterol was determined indirectly by the amount of generated H2O2according to the fluorescence quenchingsignal. The fluorescence decrease was found to be directly related to the cholesterolconcentration, which showed a linear detection range from0.2to200M with adetection limit of0.15M. The present method was convenient and demonstrateddesirable selectivity. Moreover, this method provided an alternative platform fordetecting other substrates through the oxidation by its O2dependent oxidases whichcould generate H2O2. The platform also held a potential application for the detection ofO2dependent oxidases assay in the biological complex system.（3） On the basis of double strand DNA templated synthesized fluorescent coppernanoclusters （Cu NCs）. A novel label-free fluorescent strategy for alkalinephosphatase （ALP） assay was developed. This method relied on the strong interactionbetween pyrophosphoric acid （PPi） substrate and Cu2+, which would hamper theeffective formation of fluorescent Cu NCs, leading to a low fluorescence signal. In thepresence of ALP, ALP catalyzed the hydrolysis of PPi and hence prohibited thecomplexation between PPi and Cu2+, facilitating the fromation of fluorescent Cu NCsthrough the reduction by ascorbate in the presence of dsDNA templates. Thus thefluorescence intensity was recovered, and the fluorescence enhancement wascorrelated to the concentration of ALP. The detection limit of ALP was estimated to be0.096nM and detection range was from0.1to2.5nM. The present method waslabel-free, simple, fast and high selective and sensitive for ALP assay. Additionally,this method worked well in complex biological samples. The proposed assay using PPisubstrate may hold potential applications in the diagnosis of ALP-related diseasesunder physiological conditions.

Related Dissertations

  1. A New Method for Thrombin Detection by Using Aptamers and Gold Nanoparticles,Q55
  2. The Process of Cysteine Self-assembly on Gold Nanoparticle Modified Electrodes and Their Application,TB383.1
  3. The Application of Ordered Mesoporous Carbon and Glod Nanoparticles Composite in Bioensor,TB383.1
  4. The Synthesis, Assembly, and Property of Core-shell Structured Noble Metal Nanomaterials,TB383.1
  5. Synthesis of Silver Nanoparticles on Modified Multi-walled Carbon Nanotubes and Their Antimicrobial Effects,TB383.1
  6. Metal Nanoparticles Prepared in Spherical Polyelectrolyte Brush Nanoreactor and Their Catalytic Activity,TB383.1
  7. Study on the Sensing Interfaces Fabrication of Electrochemical Impedance Immunosensor and the Application for the Detection of Polycyclic Aromatic Hydrocarbons,TP212.2
  8. Dendrimer coated gold nanoparticles as non-viral vectors for gene transfer studies,R450
  9. Gold nanoparticles synthesis , surface modification and biological applications,TB383.1
  10. Preparation and Photo-catalytic Properties of the Visible Catalytic Materials Hybrid Gold Nanoparticles,X52
  11. Study on Synthesis of Ester-soluble Polyurethane and Application in Ink,TQ638
  12. Application of Biofunctionalized Nanoparticles for Detection of Escherichia Coli O157:H7,R155
  13. Optical Biosensor Based on Organic Nano-functional Film,TB383.1
  14. Fabrization and Application of Polymer/noble Metal-nanoparticle Nanocomposites,TB383.1
  15. Study of Effects of Silver Ions and Silver Nanoparticles on Bacteria Based on Microscopy Imaging Techniques,TB383.1
  16. Application of Allele-specific PCR in SNP Differentiation and Ferritin Nanoparticle Chemiluminescence Determination,TB383.1
  17. Synthesis and Application of Unilateral Divergent TEG-PAMAM Dendrimer,O631.3
  18. Aptamer-based Cancer Cell Detection and Study on the Cytocompatibility of Carbon Nanotubes Nanocomposites,R733.7
  19. Preparation of new bio- electrochemical sensors,TP212.2
  20. Studies on Competitive Mechanism Triggered Signal Amplification Based Aptasensors,Q503
  21. Fabrication of SERS-active Substrates and Their Utilization for Detection of Amino Acids and Bacteria Biomarkers,Q503

CLC: > Biological Sciences > Biochemistry > Enzymes
© 2012 www.DissertationTopic.Net  Mobile