Difunctional immunochromatographic assay based on magnetic quantum dot for ultrasensitive and simultaneous detection of multiple mycotoxins in foods

There is a strong need for the development of a sensitive biosensor for real-time monitoring mycotoxins contamination in real food samples. Here, we reported a multiplexed immunochromatographic assay (ICA) using functionalized magnetic-quantum dot (QD) as capture/detection difunctional immunoprobes that can simultaneously and sensitively detect aflatoxin B1 (AFB1), ochratoxin A (OTA), and fumonisin B1 (FB1) in food. The antibodies-modified multilayer magnetic-QD nanobeads (MagQBD) allowed effective capture of three target mycotoxins from complex solution and simultaneously detect them on one ICA strip through fluorescence signal reading. The detection sensitivity of MagQBD-ICA was markedly improved due to the signal amplification of the multilayer QD shell and target enrichment. With capture/detection strategy, multiplexed detection of AFB1, OTA, and FB1 was conducted, resulting in low detection limits of 0.42, 11.48, and 4.21 pg mL –1 , respectively. The excellent accuracy, specificity, and stability of the method were further confirmed by testing actual samples including rice, peanut, corn and juices. Results suggested the great potential of MagQBD-ICA for practical detection of mycotoxins-contaminated food. • Magnetic-fluorescence ICA biosensor for multiplex detection of mycotoxins was first proposed. • Multilayer magnetic-QD nanobead was employed as capture/detection difunctional immunoprobes. • Accurate and sensitive identification of multiple mycotoxins in real foods was achieved. • The detection limits for three target mycotoxins reached pg/mL level.