A sensitive immunochromatographic assay using colloidal gold-antibody probe for rapid detection of fumonisin B_1 in corn

摘要

A sensitive immunochromatographic assay (ICA) using a colloidal gold-antibody probe for the rapid detection of fumonisin B_1 (FB_1) in corn samples was developed. The colour density of the test line correlated with the concentration of FB_1 in the range 2-40 ng ml~(-1) by the assay, and the detection limit for FB_1 was 2 ng ml~(-1). The linear range for FB_1 was 50-1000 μg kg~(-1), and the visual limit detection of the test was 1000 μg kg~(-1) in corn samples. The ICA to detect FB_1 is sensitive, specific and rapid. Specific anti-FB_1 monoclonal antibody (mAb) and FBrOvalbumin (FB_1-OVA) conjugate antigen were prepared. FB_1 mAb, labelled with colloidal gold, was used as the probe on the immunochromatographic strip. FB_1-OVA and goat-anti-mouse IgG were coated onto a nitrocellulose (NC) membrane as test lines and control lines, respectively. FB_1 in samples will competitively combines the FB_1 mAb with the FB_1-OVA in an NC membrane and the results are directly observed by the colour of the detection and quality control lines. The concentrations of FB_1 mAb labelled with colloidal gold, detecting antigen and goat anti-mouse IgG, were optimised. The results indicate that the test strip is specific for FB_1 with no cross-reactivity to other toxins. The strip assay for FB_1 was simple, only needing one step without complicated assay performance and expensive equipment, and the total time for visual evaluation was less than 10 min. A survey of 24 corn samples from Hefei, China, was performed with the test strip and HPLC, and the detection results showed that the developed ICA and the HPLC were in excellent agreement. Hence, the developed ICA can be used as a method for rapid detection of FB_1 in corn samples.