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Nano-Probe Based DNA Hybridization Analysis and Immunoassay

Author: LiJingQuan
Tutor: ShiYongZuo
School: Jiangnan University
Course: Nutrition and Food Hygiene
Keywords: Nanoprobe DNA hybridization Immunoassay Chemiluminescence Magnetic separation Silver enhancement
CLC: R346
Type: Master's thesis
Year: 2008
Downloads: 198
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Abstract

DNA hybridization analysis and immunological analysis is of great significance in the life sciences, is widely used in biology, medicine and diagnosis. The limitations of existing analytical methods prompted researchers to actively study general applicability, easy operation, high sensitivity detection of DNA hybridization and immunoassays. This article will combine the nanoprobe technology and a highly sensitive chemiluminescence technology used in the detection of DNA hybridization and immunoassays, the specific sequence of oligo nucleotide the human IgG aflatoxin B1 minim detection, achieved satisfactory results. ₂ O ₄ / Au core-shell composite nano the particles labeled Thiolated Salmonella-specific oligonucleotide sequences nanogold-labeled the Salmonella another specific oligonucleotide sequence to of CoFe , by DNA hybridization reaction and Salmonella specific target DNA sequence complementary to form a sandwich structure. After magnetic separation, removal of other hybrid part, magnetic separation is part of the gold nanoparticle dissolution Au ^{3 , combined with luminol chemiluminescence system to achieve highly sensitive detection of target DNA. The results show that the luminous intensity and the concentration of the target DNA the 1-100 pmol · L ^{-1 range correlation, target DNA detection limit was 0.3 pmol · L ^{-1 (3S / N), the relative standard deviation was 3.6% (10 pmol · L ^{-1 , n = 7). Core-shell composite nano-particles in CoFe2O4/Au at the same time as the carrier with the goat anti-human IgG to build the composite structure of the capture probe, the first with the target analyte human IgG immune response occurs, the captured human IgG secondary antibodies labeled with gold nanoparticles (gold standard goat anti-human IgG) immune response occurs, forming a sandwich structure; by magnetic separation to remove unbound material interference, become isolated labeled gold nanoparticles dissolution Au ^{3 , and Au ^{3 < / sup> catalyzed luminol chemiluminescence analysis to achieve the target material human IgG highly sensitive detection method. Experiments under optimized conditions, the intensity of the chemiluminescence of human IgG concentration at 2-100 ng · mL ^{-1 range a good linear relationship between the detection limit of 0.5 ng · mL ^{- 1 . Rapid and sensitive detection of aflatoxin B1 in food safety testing work is of great significance. This paper established two silver enhanced gold nanoparticles labeled probe of high sensitivity immunoassay method. The first method with aflatoxin B1 (AFB1) antibody and the gold labeled antigen, the analyte antigen competitive immune reaction, and then adding a silver enhancement solution, gold nuclear deposition growth of silver, to determine the analyte by detecting absorbance AFB ₁ content, the method detection limit up to 0.01 ng · mL ^{-1 . The second method the first of a method based on silver chemical dissolution, the amount of silver deposited by chemiluminescent detection to determine the content of analyte AFB1, the detection limit of the method can be achieved 0.002 ng · mL ^{-1 . The paper has also established a mark of gold nanoparticles - silver enhanced - Chemiluminescence new method of detection of Salmonella. Salmonella capture probe, the gold standard Salmonella DNA hybridization between the probe and the Salmonella target nucleic acid sequences, to form a sandwich complex, and then the marker gold nanoparticle surface selective deposition of silver, and the first signal amplification by silver enhancement; subsequent to combined dissolution chemiluminescence detection technology, signal a second enlarged. The results show that, under optimized conditions, the CL intensity and the concentration of target DNA 1-1000 fmol · L ^{-1 range correlation, target DNA detection limit of 0.3 fmol · L ^{-1 (3S / N), the relative standard deviation was 2.2% (10 fmol · L ^{-1 , n = 7).}}}}}}}}}}}}}

Nano-Probe Based DNA Hybridization Analysis and Immunoassay

Abstract

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