Dissertation > Excellent graduate degree dissertation topics show

Electrochemiluminescent Biosensor Based on Magnetic Nanoparticles Functionalized by Nanomaterials and Aptamer

Author: YangFeng
Tutor: HaiHong；LiJianPing
School: Guilin University of Technology
Course: Analytical Chemistry
Keywords: Magnetic nanoparticles Electrochemiluminescence DNA sensor Quantum dots DTPA
CLC: TP212.3
Type: Master's thesis
Year: 2013
Downloads: 1
Quote: 0
Read: Download Dissertation

Abstract


(1) An electrochemiluminescence （ECL） DNA bisensor based on Fe3O4/Aucore/shell nanoparticle films modified magnetic controlled glassy carbon electrode（MCGCE） was developed by using quantum dots （QDs） as labels of reporter probeDNA. The DNA biosensor was based on a sandwich detection strategy, whichinvolves5’-SH capture probe immobilized on magnetic nanoparticles （MNPs）,target and5’-NH2reporter probe NH2-3’. After hybridization reaction, thioglycollicacid-capped CdTe QDs are attached to the end amino group of the sandwich hybrids.The fabrication and hybridization process of the DNA biosensor were characterizedby cyclic voltammetric methods. The responsive ECL intensity was linearly relatedto the target nucleic acid concentration in the range of1.0×10-131.0×10-11mol/L,with the detection limit of1.8×10-14mol/L. In addition, the ECL biosensorexhibited high sensitivity, good selectivity, satisfying stability, reproducibility andrepeatability.（2） PDTPA-EG and PDTPA-EG@CdTe were synthesized in the assay.According to the hybrid theory of the DNA （or ss-DNA）, a DNA electrochemicalsensor was fabricated based on the electrochemiluminescence of the quantum dots.On the surface of the magnetic controlled golden electrode （MCGE）,5’-SH-ssDNA,the capture probe, got on to the Fe3O4/Au magnetic nanoparticles by self-assemblyand it could couple with the complementary end of the target DNA chine to form thedsDNA; the complex could then combine with the signal probe3’-NH2-ssDNA toform the sandwich type hybrid DNA; at last the PDTPA-EG@CdTe nanoparticleswere fabricated on the hybrid DNA. cyclic voltammogram（CV） and electrochemicalimpedance spectroscopy （EIS） method were employed to determine the fixation,hybridization of the DNA and the characterization of the PDTPA-EG@CdTe nano-composites. The linear range between the concentration of the target DNA and theresponse ECL signals is1.0×10-161.0×10-14mol/L with the detection limit of3.0×10-17mol/L. The sensitivity of the biosensor is dramatically enhanced with the helpof PDTPA-EG@CdTe.（3） A layer of Aptamer probe with hairpin structure was modified on thesurface of Fe3O4/Au magnetic nanoparticles （Fe3O4/Au-Aptamer）."stem-loop"structure of hairpin aptamer was opened when adding Pb2+. Then G-quadruplex wasformed, exposing3’-NH2, which bound to CdTe quantum dots. Thus the magneticnanoparticles were separated and enriched on the surface of the magnetic controlled gold electrode （MCGE）. By this means,"Turn-on" electrochemiluminescence （ECL）sensor for Pb2+detection using quantum dots was constructed. The changes of thestructure of aptamer were characterized by cyclic voltammetry, AC impedance, andUV-Vis absorption spectroscopy. Pb2+concentration and ECL signal presented alinear relationship in the range of2.0×10-101.0×10-8mol/L. The detection limitwas1.08×10-11mol/L. In addition, the biosensor showed good selectivity, stabilityand reproducibility.（4） A layer of Aptamer probe with duplex structure was modified on thesurface of Fe3O4/Au magnetic nanoparticles （Fe3O4/Au-dsDNA）.Pb2+-driven Aptamerprobe which is constructed based on a DNA duplex-quadruplex exchange is utilizedfor the highly selective and sensitive detection of Pb2+. The power of thisFe3O4/Au-dsDNA device originates from the excellent efficiency of Pb2+forstabilizing G-quadruplexes, which makes the DNA duplex unwind thereby driving thedevice. This device can be reset to the original state by addition of a strong Pb2+chelator EDTA,endowing the device with good reusability. In the whole process,thesignal readout is modulated via a Ru（phen）32+probe binding to and being releasedfrom the DNA druplex. Such a Fe3O4/Au-dsDNA device can serve as a novelelectrochemiluminescence sensor for Pb2+detection with high selectivity andsensitivity.

Related Dissertations

  1. Electrochemiluminescence Immunosensor Based on Nanocomposite Film of Surface Modified and Assembled CdS Nanoparticles,TP212.2
  2. Construction of Multi-responsive Gene Vector Via Layer-by-Layer Assembly,TB383.1
  3. Aqueous Synthesis and Property Studies of Citrate-stabilized CdS Quantum Dots,O614.242
  4. Study on Belt-type ZnO Photoanode for Dye-sensitized and Quantum-dot Sensitized Solar Cells,TM914.4
  5. Synthesis and Water-soluble Modification of Quantum Dots,O649
  6. Preparation and Responding Characterization of Urea Molecularly Imprinted Electrochemical Sensor,TP212.2
  7. Fabrication of Electrochemical DNA Biosensors Based on Nanomaterials,TP212.3
  8. Study on the Feasibility of Angelica Sinensis Polysaccharide as Magnetic Nano-material Carrier,R283
  9. The Applications of L-cysteine Capped CdTe Quantum Dots as Fluorescent Probes,R341
  10. Study on Some Local Anesthetics Analysis by Capillary Electrophoresis with Electrochemiluminescence,R917
  11. Study on the Synthesis and the Properties of Semiconductor Quantum Dots via Poly-phase System,O614.242
  12. Study on Three-Dimensional Photonic Crystal Operate the Illumination Properties of CdTe Quantum Dots,O614.242
  13. Preparation and Modification of ZnO Quantum Dots,O614.241
  14. Preparation of Tris (2,2’-bipyridyl) Ruthenium Encapsulated Liposome and Its Applications in Electrochemiluminescent Immunoassay,R392.1
  15. Studies on Synthesis and Luminescence Properties of CdSe Quantum Dots,O614.242
  16. Synthesis and Application of Cucurbit[6] Uril and Its Derivatives,O621.2
  17. Fabrication and Properties of YxGd2-xO3:Eu Powders and Nano-Sized Fe3O4/Y2O3:Eu Core-Shell Materials,TB383.1
  18. Study of Several DNA Sensors Based on Nanoparticle Label,TB383.1
  19. Preparation、 Characterization of Fe3O4 Magnetic Nanoparticles and Application in Separation and Detection,TB383.1
  20. Preparation, Characterization and Analytical Application of CdTe Quantum Dots as Fluorescent Probes,O471.1
  21. Theoretical Studies on the Electronic Properties in Semiconductor Quantum Dots,O471.1

CLC: > Industrial Technology > Automation technology,computer technology > Automation technology and equipment > Automation components,parts > Transmitter ( converter),the sensor > Biological sensors,medical sensors
© 2012 www.DissertationTopic.Net  Mobile