Aflatoxin B1 (AFB1) is one of the major mycotoxins, which naturally occurs in food and agricultural products. In this study, a cyclic peptide (CVPSKPGLC) mimicking AFB1 was used to develop a biotinylated peptide-based immunoassay (bp-ELISA) for AFB1 determination. This cyclic peptide was isolated from a commercially available phage-displayed random 7-mer cyclic peptide library, and then synthesized chemically. Instead of phage particles, the peptide was biotinylated and used to detect AFB1 by bp-ELISA, with an IC50 of 0.92 ng/mL, which was approximately 60-fold better than that of phage ELISA. Good recoveries (83-102%) were obtained in spiked rice and corn samples, which were further validated by high-performance liquid chromatography-fluorescence detector. As better sensitivities (0.92-1.21 ng/mL) were obtained by bp-ELISA even using selected anti-AFB1 antibodies prepared previously in laboratory, this cyclic peptide is suitable as a substitute for synthetic competitive AFB1 antigens in food contamination monitoring. Graphical abstract.
Keywords: Aflatoxin B1; Cyclic peptide; Immunoassay; Phage display.