title: Multifunctional magnetic bead-based electrochemical immunoassay for the detection of aflatoxin B1 in food.
abstract: A sensitive and reusable electrochemical immunoassay for aflatoxin B(1) (AFB(1)) in food has been developed. A multifunctional magnetic bead (MMB) was initially synthesized using magnetic CoFe(2)O(4) nanoparticle as the core and Prussian blue nanoparticle (PBNP)-doped silica as the shell, and then the prepared MMB was used as an affinity support for the immobilization of the AFB(1)-bovine serum albumin conjugate (AFB(1)-BSA). With the aid of an external magnet, the AFB(1)-BSA-conjugated MMBs were attached on the surface of an indium tin oxide (ITO) electrode. Gold nanoparticles, labeled with horseradish peroxidase (HRP)-bound anti-AFB(1) antibodies (HRP-anti-AFB(1)), were employed as detection antibodies. With a competitive immunoassay format, the concentrations of AFB(1) in samples were measured in PBS (pH 7.0) by using PBNP-doped MMBs as the mediator, HRP-anti-AFB(1) as the tracer and hydrogen peroxide (H(2)O(2)) as the enzyme substrate, and the linear range was 0.05-12 ng/mL with a detection limit of 6.0 pg/mL AFB(1) (at 3sigma). Intra- and inter-assay coefficients of variation were less than 7.5%. In addition, the content of AFB(1) in red paprika specimens has been assayed by the developed immunoassay and a commercially available enzyme-linked immunosorbent assay (ELISA) method, respectively, and consistent results were obtained. The as-prepared immunoassay provides a promising approach for the screening of organic pollutants because it is simple, rapid, highly sensitive, specific, and without the need of sample pre-concentration.
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: Zhaoyang
authors.initials: Z
authors.lastname: Zhong
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.forename: Dietmar
authors.initials: D
authors.lastname: Knopp
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis* / Q000276:immunology / Q000302:isolation & purification; D000818:Animals; D000906:Antibodies / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods; D002417:Cattle; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes / Q000706:statistics & numerical data; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005295:Ferrocyanides / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000737:chemistry; D007118:Immunoassay / Q000379:methods*; D018189:Immunomagnetic Separation; D057230:Limit of Detection; D008280:Magnetics / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry; D049329:Nanostructures; D036103:Nanotechnology; D017971:Tin Compounds / Q000737:chemistry*
chemical_list: D000906:Antibodies; D005295:Ferrocyanides; D017971:Tin Compounds; C109984:indium tin oxide; D006046:Gold; D016604:Aflatoxin B1; D006735:Horseradish Peroxidase; C000170:ferric ferrocyanide