A photothermal lateral flow immunoassay for zearalenone with high sensitivity and wide detection range

Mycotoxin zearalenone can induce reproductive toxicity and oxidative toxicity, so its on-site monitoring in foods is of great significance in food control. Herein, we develop a novel photothermal lateral flow immunoassay (LFIA) for ZEN based on gold nanoparticle loaded black phosphorus (BP-Au) nanocomposite. The self-assembled BP-Au nanocomposite showed a dark purple color and an excellent photothermal conversion efficiency of 69.62%, better than either BP or Au. Therefore, it was developed into not only a colorimetric probe for qualification but also a sensitive photothermal probe for quantification. Our competitive LFIA showed a detection limit down to 17.2 ng/kg and an ultrawide linear range of 10 pg/mL-106 pg/mL in its photothermal mode. The recoveries of ZEN in cereals were between 91.8% and 120.2%. The wide detection range of our method allows monitoring the variation of trace ZEN content to evaluate food storage and transportation conditions, but also gives regulators a fast and accurate picture of the level of ZEN exceeding limits without relying on laboratory chromatography.