Engineered gold nanoparticles as multicolor labels for simultaneous multi-mycotoxin detection on the immunochromatographic test strip nanosensor

Herein, we report a multicolor immunochromatographic test strip (ICTS) nanosensor for the rapid and simultaneous visual detection of fumonisin B1 (FB1), zearalenone (ZEN), ochratoxin A (OTA), and aflatoxin B1 (AFB1). Four colored AuNPs, including gold nanospheres (red), gold nanocacti (purple), gold nanoflowers (blue), and hyperbranched Au plasmonic blackbodies (black), were synthesized and functionalized with the corresponding antibodies to target each analyte. The developed multicolor platform improved bare-eye-based visual detection ability with cut-off values of 120, 60, 2.5, and 5 ng/mL for FB1, ZEN, OTA, and AFB1, respectively. The limits of detection for FB1, ZEN, OTA, and AFB1 were calculated as 3.27, 0.70, 0.10, and 0.06 ng/mL, respectively, and the average recoveries of the four mycotoxins ranged from 82.36% to 116.23% with a small coefficient of variation (below 12.98%). Accuracy, stability, reliability, and practicability were demonstrated by analyzing artificially and naturally contaminated corn samples. In summary, the designed multicolor ICTS nanosensor can serve as an alternative rapid diagnostic platform enabling the sensitive, simultaneous, and on-site screening detection of mycotoxins and other analytes.