title: Magnetic bead-based colorimetric immunoassay for aflatoxin B1 using gold nanoparticles.
abstract: A competitive colorimetric immunoassay for the detection of aflatoxin B1 (AFB) has been established using biofunctionalized magnetic beads (MBs) and gold nanoparticles (GNPs). Aflatoxin B1-bovine serum albumin conjugates (AFB-BSA) modified MBs were employed as capture probe, which could specifically bind with GNP-labeled anti-AFB antibodies through immunoreaction, while such specific binding was competitively inhibited by the addition of AFB. After magnetic separation, the supernatant solution containing unbound GNPs was directly tested by UV-Vis spectroscopy. The absorption intensity was directly proportional to the AFB concentration. The influence of GNP size, incubation time and pH was investigated in detail. After optimization, the developed method could detect AFB in a linear range from 20 to 800 ng/L, with the limit of detection at 12 ng/L. The recoveries for spiked maize samples ranged from 92.8% to 122.0%. The proposed immunoassay provides a promising approach for simple, rapid, specific and cost-effective detection of toxins in the field of food safety.
authors.affiliation: Institute of Hydrochemistry and Chemical Balneology, Chair for Analytical Chemistry, Technische Universität München, Marchioninistrasse 17, Munich 81377, Germany. xu.wang@tum.de.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.affiliation: Institute of Hydrochemistry and Chemical Balneology, Chair for Analytical Chemistry, Technische Universität München, Marchioninistrasse 17, Munich 81377, Germany. reinhard.niessner@ch.tum.de.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.affiliation: Institute of Hydrochemistry and Chemical Balneology, Chair for Analytical Chemistry, Technische Universität München, Marchioninistrasse 17, Munich 81377, Germany. dietmar.knopp@ch.tum.de.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Knopp
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis* / Q000276:immunology; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation; D002417:Cattle; D003124:Colorimetry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006046:Gold / Q000737:chemistry*; D007118:Immunoassay / Q000295:instrumentation*; D018189:Immunomagnetic Separation / Q000295:instrumentation*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D006046:Gold; D016604:Aflatoxin B1