Ultrasensitive and green electrochemical immunosensor for mycotoxin ochratoxin A based on phage displayed mimotope peptide.

Here, we demonstrated a new approach for development of an ultrasensitive and green electrochemical immunosensor for Ochratoxin A (OTA). Phage displayed mimotope peptide of OTA was used as mimics of conventional competing antigen, which is chemical synthesized with toxic mycotoxins OTA as raw material, in a competitive sensing platform. The working electrode was modified by polyethylene glycol (PEG) for the purpose of immobilizing antibody effectively. Under the optimized test condition, the limit of detection (LOD) of the established immunosensor was 2.04 fg/mL, and the linear range was 7.17-548.76 fg/mL. Specific measurement of this established method was conducted by testing cross-reactivity of other common mycotoxins, the result showed that mimotope peptide-based immunosensor has negligible cross-reactivity with other mycotoxins. Furthermore, the novel concept of phage displayed mimotope peptide-based immunosensor may provide a potential application in general method for the ultrasensitive detection of various toxic small molecules in food.