title: Flow-injection electrochemical immunosensor for the detection of human IgG based on glucose oxidase-derivated biomimetic interface.
abstract: A newly flow-through electrochemical immunosensor for monitoring IgG in human serum has been developed by using core-shell SiO(2)/Au nanocomposites and poly(amidoamine) G4 dendrimer as matrices. The ferrocenecarboaldehyde-labeled anti-IgG biomolecules were initially chemisorbed onto the nanoparticle surface, and then glucose oxidase (GOx), as a blocking reagent instead of bovine serum albumin (BSA), was backfilled onto the modified surface. The formation of the antibody-antigen complex by a simple one-step immunoreaction between the immobilized anti-IgG and IgG in sample solution introduced a barrier of direct electrical communication between the immobilized GOx and the base surface, and decreased the immobilized GOx toward the catalytic oxidation of glucose. The performance and factors influencing the performance of the immunosensor were evaluated. Under optimal conditions, the linear range of the developed immunosensor by using GOx as enhancer was from 5.0 x 10(-6) to 9.6 x 10(-4)mol/L with a detection limit of 8.0 x 10(-7)mol/L IgG (at 3delta), while the detection limit by using BSA was 1.5 x 10(-5)mol/L IgG (at 3delta) with the linear range from 3.5 x 10(-5) to 1.2 x 10(-3)mol/L. The selectivity, reproducibility and stability of the proposed immunosensor were acceptable. The IgG contents in 37 human serum samples obtained by the proposed method are identical with the data of clinical laboratory.
authors.affiliation: Chair for Analytical Chemistry, Institute of Hydrochemistry, Technische Universität München, Marchioninistrasse 17, D-81377 München, Germany.
authors.forename: Dianping
authors.initials: D
authors.lastname: Tang
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.forename: Dietmar
authors.initials: D
authors.lastname: Knopp
mesh_terms: D040761:Biomimetic Materials; D015374:Biosensing Techniques / Q000295:instrumentation*; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017022:Flow Injection Analysis / Q000295:instrumentation*; D005949:Glucose Oxidase / Q000737:chemistry*; D007118:Immunoassay / Q000295:instrumentation*; D007074:Immunoglobulin G / Q000032:analysis*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D007074:Immunoglobulin G; D005949:Glucose Oxidase