title: Magnetic bead-based fluorescence immunoassay for aflatoxin B1 in food using biofunctionalized rhodamine B-doped silica nanoparticles.
abstract: A simple and sensitive fluorescence immunoassay for the detection of aflatoxin B(1) (AFB(1), as a model compound) in food was developed using AFB(1)-bovine serum albumin conjugate (AFB(1)-BSA)-functionalized magnetic beads as immunosensing probes. The recognition elements were prepared by doping of rhodamine B (RB) fluorophore into silica nanoparticles followed by immobilization of monoclonal anti-AFB(1) antibodies on the silica shell. Based on a competitive-type immunoassay format, the assay was performed both in low-binding polypropylene 96-well microtiter plates (MTPs) and in an automated sequential injection (SI) format. Similar detection limit (LOD) of 0.2 ng mL(-1)vs. 0.1 ng mL(-1) but narrower dynamic working linear range of 0.5-7 ng mL(-1)vs. 0.5-30 ng mL(-1) was obtained toward AFB(1) standards with the flow setup compared to the MTP format. Intra-batch assay precision was substantially improved (≤5.3% vs.≤8.7%) by resorting to the SI manifold. The proposed method features unbiased identification of negative (blank) and positive samples. No significant differences at the 95% confidence level were encountered in the analysis of naturally contaminated peanut samples between the proposed immunoassay and liquid chromatography for determination of AFB(1).
authors.affiliation: Institute of Hydrochemistry, Technische Universität München, Marchioninistrasse 17, D-81377 München, Germany.
authors.forename: Dianping
authors.initials: D
authors.lastname: Tang
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Yu
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.forename: Manuel
authors.initials: M
authors.lastname: Miró
authors.forename: Dietmar
authors.initials: D
authors.lastname: Knopp
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002417:Cattle; D052203:Ferrosoferric Oxide / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D005504:Food Analysis / Q000379:methods*; D007118:Immunoassay / Q000379:methods*; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D000911:Antibodies, Monoclonal; D005456:Fluorescent Dyes; D012235:Rhodamines; D012710:Serum Albumin, Bovine; D012822:Silicon Dioxide; D016604:Aflatoxin B1; C029773:rhodamine B; D052203:Ferrosoferric Oxide