title: Electrochemical immunosensor with aptamer-based enzymatic amplification.
abstract: An electrochemical immunosensor is reported by using aptamer-based enzymatic amplification with immunoglobulin E (IgE) as the model analyte. In this method, the IgE antibody is covalently immobilized as the capture probe on the gold electrode via a self-assembled monolayer of cysteamine. After the target is captured, the biotinylated anti-IgE aptamer is used as the detection probe. The specific interaction of streptavidin-conjugated alkaline phosphatase to the surface-bound biotinylated detection probe mediates a catalytic reaction of ascorbic acid 2-phosphate substrate to produce a reducing agent ascorbic acid. Then silver ions in the solution can be reduced, leading to the deposition of metallic silver on the electrode surface. The amount of deposited silver, which is determined by the amount of IgE target bound on the electrode surface, can be quantified using the stripping voltammetry. The results obtained demonstrated that the electrochemical immunosensor possesses high specificity and a wide dynamic range with a low detection limit that possibly arises from the combination of the highly specific aptamer and the highly sensitive stripping determination of enzymatically deposited silver.
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China.
authors.forename: Kejun
authors.initials: K
authors.lastname: Feng
authors.forename: Yan
authors.initials: Y
authors.lastname: Kang
authors.forename: Jing-Jin
authors.initials: JJ
authors.lastname: Zhao
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Liu
authors.forename: Jian-Hui
authors.initials: JH
authors.lastname: Jiang
authors.forename: Guo-Li
authors.initials: GL
authors.lastname: Shen
authors.forename: Ru-Qin
authors.initials: RQ
authors.lastname: Yu
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D052157:Aptamers, Nucleotide / Q000378:metabolism*; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000378:metabolism; D004563:Electrochemistry; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007073:Immunoglobulin E / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D007201:Indicator Dilution Techniques; D008274:Magnesium
chemical_list: D052157:Aptamers, Nucleotide; D004800:Enzymes, Immobilized; D007073:Immunoglobulin E; D001710:Biotin; D000469:Alkaline Phosphatase; D008274:Magnesium