title: Metal-enhanced fluorescent probes based on silver nanoparticles and its application in IgE detection.
abstract: In this paper, a novel metal plasmon coupled with an aptamer-nucleotide hybridized probe was fabricated and applied for protein detection. The specific aptamer and single-strand oligonucleotide were chemically bound to silver nanoparticles (AgNPs), and Cy5-labeled, complementary single-strand oligonucleotides were hybridized with the particle-bound oligonucleotides. The hybridized DNA duplexes were regarded as rigid rods that separated the fluorophore Cy5 and the surface of AgNPs to reduce the competitive quenching. Using a model system comprising human immunoglobulin E (IgE) as the analyte and goat antihuman IgE as immobilized capture antibody on glass slides, we demonstrate that the detection performance of the synthetic probe was superior to the aptamer-based fluorescent probes. The results showed a good linear correlation for human IgE in the range from 10 ng/ml to 6.25 μg/ml. The detection limit obtained was 1 ng/ml, which was 50 times lower than that using Cy5 oligonucleotide/aptamer hybrid duplex (Probe2) due to the metal-enhanced fluorescence effect. This new strategy opens the possibility for the preparation of high-sensitivity detection probes based on metal nanoparticles.
authors.affiliation: Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Wei
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Li
authors.forename: Maika
authors.initials: M
authors.lastname: Vuki
authors.forename: Yu
authors.initials: Y
authors.lastname: Fan
authors.forename: Wenying
authors.initials: W
authors.lastname: Zhong
authors.forename: Danke
authors.initials: D
authors.lastname: Xu
mesh_terms: D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry / Q000276:immunology; D052157:Aptamers, Nucleotide / Q000737:chemistry; D002232:Carbocyanines / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007073:Immunoglobulin E / Q000032:analysis* / Q000276:immunology; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D012834:Silver / Q000737:chemistry*
chemical_list: D055910:Antibodies, Immobilized; D052157:Aptamers, Nucleotide; D002232:Carbocyanines; D005456:Fluorescent Dyes; C085321:cyanine dye 5; D007073:Immunoglobulin E; D012834:Silver