Blue-green-red multicolor upconversion nanoparticles based fluorescence immunoassay for simultaneous detection of three mycotoxins in cereals

In this work, a fluorescence immunoassay based on multicolor upconversion nanoparticles (UCNPs) and magnetic separation was established for simultaneous detection of aflatoxin B1 (AFB1), zearalenone (ZEN), and ochratoxin A (OTA) in cereal samples. Anti-AFB1, anti-ZEN, and anti-OTA antibody is connected to blue-green–red UCNPs as multicolor signal probe respectively, and the AFB1, ZEN and OTA coating antigen is connected to magnetic polystyrene microspheres (MPMs) as capture probe respectively. Based on a competitive form, the capture probe and the target competitively bind with signal probe, and the fluorescence intensity of the obtained immune complexes (signal probe@capture probe) at 477 nm, 544 nm, and 662 nm was measured to quantitate AFB1, ZEN, and OTA, respectively. The detection limit (LOD) of AFB1, ZEN, and OTA is 1.0 × 10-3 μg L-1, 9.8 × 10-4 μg L-1, and 5.6 × 10-4 μg L-1, respectively. This assay can achieve rapid, sensitive, accurate, high-throughput, simultaneous quantitative detection of three mycotoxins in cereal samples.