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.
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