Multicolor quantum dot nanobeads for simultaneous multiplex immunochromatographic detection of mycotoxins in maize

The presence of multiple mycotoxins in agricultural products and feed seriously threatens human and animal health. We report a multiplex immunochromatographic assay (mICA) with three test lines and one control line for the simultaneous qualitative detection of zearalenone (ZEN), ochratoxin A (OTA), and fumonisin B-1 (FB1) in corn samples. Three quantum dot (QD) nanobeads (QBs) with distinguishable yellow, orange, and red luminescence were synthesized via encapsulating CdSe/ZnS QDs with 575 and 615 nm emissions into polymer nanobeads. The as-prepared QBs were then conjugated with anti-OTA monoclonal antibodies, anti-FB1 monoclonal antibodies, and anti-ZEN monoclonal antibodies to develop a tricolor QB-based mICA for the detection of OTA, FB1, and ZEN, respectively. The visual detection limits of our mICA for OTA, FB1, and ZEN under the developed conditions reached up to 5, 20, and 10 ng/mL within 10 min, respectively. The accuracy, repeatability, selectivity, and practicability of our proposed mICA were evaluated by using naturally contaminated maize samples. Also, a high correlation in simultaneously testing three mycotoxins was observed between the developed mICA and the well-accepted ultra-performance liquid chromatography. In brief, this work demonstrated the feasibility of our fabricated tricolor QB-based mICA for rapid and simultaneous monitoring of multi-mycotoxins in agro-food samples.