Quantum dot nanobead-based fluorescent immunochromatographic assay for simultaneous quantitative detection of fumonisin B1, dexyonivalenol, and zearalenone in grains

Abstract

The mycotoxins in grains is a serious threat to the health of humans and animals. In this study, we demonstrated an approach for development of a fast and sensitive fluorescent immunochromatographic assay for fumonisin B1 (FB1), deoxynivalenol (DON) and zearalenone (ZEN) detection using quantum dots nanobeads (QDNBs, 100 nm). Amplification of the fluorescence signal of the quantum dot by nanosphere coating can significantly improve the sensitivity of immunochromatographic test strip. The detection probes (FB1-McAb@QDNBs, DON-McAb@QDNBs, and ZEN-McAb@QDNBs) were prepared using the QDNBs with 615 nm emissions coupling with three monoclonal antibodies (McAb) against FB1, DON, and ZEN, respectively, in a competitive immunochromatography platform. The surface of the QDNBs is modified with a carboxyl functional group, which facilitates the coupling of the antibody and significantly improves the sensitivity of test strip. Compared with traditional ELISA, the immunoassay based on the McAb@QDNBs is more sensitive, with IC50 of 12.66 ng/mL (FB1), 2.97 ng/mL (DON), and 0.87 ng/mL (ZEN), of which the linear range were from 2.295 ng/mL to 69.867 ng/mL (FB1), 0.465 ng/mL to 16.19 ng/mL (DON), and 0.295 ng/mL to 2.575 ng/mL (ZEN), respectively. The accuracy, repeatability, and specificity of the established test strip was evaluated by testing the spiked and natural samples. Furthermore, a high agreement was observed between the developed test strips and LC-MS/MS in simultaneously and quantitative detection of three mycotoxins. In brief, the developed approach was feasible and could be employed for simultaneously and quantitative mycotoxins detection in agricultural products.