title: Amperometric immunosensor based on toluidine blue/nano-Au through electrostatic interaction for determination of carcinoembryonic antigen.
abstract: A new current amplified immunosensor for the determination of carcinoembryonic antigen (CEA) was demonstrated in this work. The electrode architecture was fabricated by positively charged toluidine blue (TB) coated on negatively charged poly-sulfanilic acid (PSAA) modified glassy carbon electrode (GCE) surface through electrostatic interactions to form a TB/PSAA film, which provided an interface containing amine groups to assemble gold nanoparticles (nano-Au) for immobilization of carcinoembryonic antibody (anti-CEA) and horseradish peroxidase (HRP) instead of bovine serum albumin (BSA) to block sites against non-specific binding. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were employed to characterize the electrochemical properties of the modified processes. The CVs reduction current of the immunosensor charged linearly in two concentration ranges of CEA from 0.5 to 5.0 and 5.0 to 120.0 ng/ml in presence of 0.3mM H2O2 in analyte solution, and the detection limit was 0.2 ng/ml at three times background noise. The proposed method is economical, efficient and potentially attractive for clinical immunoassays.
authors.affiliation: Chongqing Key Laboratory of Analytical Chemistry, Southwest University, Chongqing 400715, PR China.
authors.forename: Xuelian
authors.initials: X
authors.lastname: Li
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.forename: Lingyan
authors.initials: L
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuo
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002272:Carcinoembryonic Antigen / Q000032:analysis* / Q000276:immunology; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D008839:Microelectrodes; D049329:Nanostructures / Q000737:chemistry; D055672:Static Electricity; D014048:Tolonium Chloride / Q000737:chemistry*
chemical_list: D002272:Carcinoembryonic Antigen; D014048:Tolonium Chloride; D006046:Gold