An Improved Chemiluminescence Immunoassay for the Ultrasensitive Detection of Aflatoxin B.

An indirect competitive chemiluminescence (CL) immunoassay based on FeO@SiO@Au magnetic nanoparticles (Au-SCMPs) has been optimized and developed for the detection of aflatoxin B (AFB). To improve the detection sensitivity and efficiency, this method combines 2′,6′-dimethylcarbonylphenyl-10-sulfopropyl acridinium-9-carboxylate 4′-NHS ester (NSP-DMAE-NHS) as a new kind of high efficient luminescence reagent with a simplified separation procedure based on the optimized Au-SCMPs. Superparamagnetic nanoparticles were coated with different sizes of Au colloids (18, 30, and 50 nm), and their capacities in immobilization of bovine serum albumin (BSA) were investigated. The BSA-AFB conjugate (BSA-AFB) was immobilized on the optimized Au-SCMPs and competed with the free AFB for specially binding the NSP-DAME-NHS-labeled anti-AFB antibody (mAb-AFB). After the indirect competitive immunoreactions and magnetic separation, the CL of the nanoparticles was measured by a homemade luminescent measurement system. Under the optimum conditions, the IC value was 0.07 ng mL and the limit of detection (LOD) of AFB was 0.01 ng mL, respectively. The result shows a much lower IC and LOD than that typically achieved by ELISA. This proposed immunoassay method was rapid, low-cost, and suitable for the detection of AFB. [ABSTRACT FROM AUTHOR]