Red-emitted AIE fluorescent microspheres based lateral flow immunoassay for the visual and quantitative detection of aflatoxin M1 in milk.

Fluorescent material-based lateral flow immunochromatographic assay (LFIA) has been widespread applied for the point-of-care test of mycotoxins. However, aggregation-caused quenching (ACQ) phenomenon of fluorescent labels seriously affects the detection performance of the methods. Herein, a red-emitted aggregation-induced emission fluorescent microspheres (AIEFMs) based LFIA was developed and firstly applied for the visual and quantitative detection of aflatoxin M1 (AFM1) in milk. The fluorescent probe was constructed by directly coupling the carboxylated AIEPMs with anti-AFM1-mAb, which demonstrated a strong AFM1-specific affinity and exceptional fluorescent characteristics. Under the optimal conditions, this AIEFMs-LFIA could achieve a rapid detection of AFM1 within 15 min, with a visual limit of detection (vLOD) of 0.1 ng/mL and a quantitative limit of detection (qLOD) of 0.01 ng/mL. The accuracy and precision of the established AIEFMs-LFIA method were assessed though the spiked milk samples, and the recoveries were in the range of 86.81 %-106.37 % with coefficients of variation below 15 %. Furthermore, the test strip exhibited a wide detection range for AFM1 (0.01-1 ng/mL) and a remarkable stability for 180 days when stored at 4 °C and 25 °C. Importantly, the results for the spiked milk samples were consistent with those of standard UPLC-MS/MS method, with a correlation coefficient of 0.9911. Overall, the newly developed AIEFMs-LFIA demonstrates significant potential for the point-of-care test of AFM1 in milk.