Magnetic bead-based fluorescence immunoassay for aflatoxin B1 in food using biofunctionalized rhodamine B-doped silicananoparticles

摘要

A simple and sensitive fluorescence immunoassay for the detection of aflatoxin B1 (AFB1, as a modelncompound) in food was developed using AFB1–bovine serum albumin conjugate (AFB1–BSA)-nfunctionalized magnetic beads as immunosensing probes. The recognition elements were prepared byndoping of rhodamine B (RB) fluorophore into silica nanoparticles followed by immobilization ofnmonoclonal anti-AFB1 antibodies on the silica shell. Based on a competitive-type immunoassay format,nthe assay was performed both in low-binding polypropylene 96-well microtiter plates (MTPs) and innan automatedsequential injection (SI) format. Similar detection limit (LOD) of 0.2 ngmLu00021 vs. 0.1ngmLu00021nbut narrower dynamic working linear range of 0.5–7 ng mLu00021 vs. 0.5–30 ng mLu00021 was obtained towardnAFB1 standards with the flow setup compared to the MTP format. Intra-batch assay precision wasnsubstantially improved (#5.3%vs.#8.7%) by resorting to the SImanifold. The proposed method featuresnunbiased identification of negative (blank) and positive samples. No significant differences at the 95%nconfidence level were encountered in the analysis of naturally contaminated peanut samples between thenproposed immunoassay and liquid chromatography for determination of AFB1.