Ovalbumin antibody-based fluorometric immunochromatographic lateral flow assay using CdSe/ZnS quantum dot beads as label for determination of T-2 toxin

This work describes an anti-ovalbumin antibody-based lateral flow immunoassay (LFI) for T-2 toxin. The antibody uses a coating antigen as a bifunctional element for universality and introduces preincubation to improve the detection limits of the method. T-2 toxin and ovalbumin-modified T-2 toxin competitively binds on the anti-T-2 toxin monoclonal antibody modified on CdSe/ZnS quantum dot beads during preincubation. The modified T-2 toxin acts as a bifunctional element that forms immuno complexes during preincubation and combines with anti-ovalbumin antibody coated in the test line through the ovalbumin terminal. Fluorescence is detected at 610 nm on the test zone following photoexcitation at 365 nm. It has a reverse dose-effect relationship with the amount of T-2 toxin. The calibration plot is linear in the 20-110 fg mL(-1) T-2 toxin concentration range, and the limit of detection (LOD) is 10 fg mL(-1), which is lower by 8-fold than that of the traditional LFI system (LOD 80 fg mL(-1)) and one order of magnitude than those of LFIs with labels of colloidal gold nanoparticles (LOD 150 fg mL(-1)) or fluorophores (LOD 190 ng mL(-1)). Universality was verified through aflatoxin B-1 detection using the established ovalbumin antibody-based LFI system (LOD 10 fg mL(-1)). The performance of the method was compared with that of established systems and a commercial ELISA kit (LOD 360 fg mL(-1)).