Nanobody-based icELISA for aflatoxin M1 in dairy products.

Nanobody has become an important tool for immunoassays because of its stability, specificity, and ease of expression. To monitor the aflatoxin M1 in dairy products, the anti-AFM1 nanobody, named M6, selected from the Bactrian camel AFM1 immune library, evaluated its properties, and developed an indirect competitive enzyme-linked immunosorbent assay (icELISA). After optimizing the parameters, including the blocking method, methanol concentrations, pH values, and ionic strength in the reaction system, a standard competitive inhibition curve was established, and methodological specificity and accuracy was verified. Results showed that Nb-M6 had a good affinity and thermal stability, the limit of detection (LOD) of Nb-icELISA was 0.111 ng/ mL, and the half maximal inhibitory concentration (IC₅₀) was 1.498 ng/ mL. The recoveries of dairy products spiked were 89.8% - 104.1%, which were in agreement with the high-performance liquid chromatography (HPLC). The Nb-icELISA is simple, convenient and can be applied to batch screening of AFM1 in dairy products. [ABSTRACT FROM AUTHOR]