Electrochemical aptasensor based on exonuclease III-mediated signal amplification for sensitive detection of vomitoxin in cornmeal

Vomitoxin (DON) residues in grains are of great concern to public health. Herein, a label-free aptasensor was con-structed to detect DON distributed in grains. Cerium-based metal-organic framework composite gold nanoparticles (CeMOF@Au) were used as substrate materials to facilitate electron transfer and provided more binding sites for DNA. The separation of DON-aptamer (Apt) complex and cDNA was achieved by magnetic separation technique based on magnetic beads (MBs), ensuring the specificity of the aptasensor. Exonuclease III (Exo III)-assisted cDNA cy-cling process strategy would be triggered when cDNA was separated and introduced to the sensing interface for further signal amplification. Under optimal conditions, the constructed aptasensor presented a wide detection range from 1 x 10-8 mg center dot mL-1 to 5 x 10-4 mg center dot mL-1 for DON, and the detection limit was 1.79 x 10-9 mg center dot mL-1, including a satisfactory recovery in cornmeal sample spiked with DON. The results showed that the proposed aptasensor had high reliability and promising application potential in detecting DON.

Automated summary

A label-free aptasensor using cerium-based metal-organic framework composite gold nanoparticles was developed for detecting vomitoxin residues in grains. The aptasensor achieved the separation of the DON-aptamer complex and cDNA using magnetic separation technique with magnetic beads, ensuring specificity. Exonuclease III-assisted cDNA cycling process strategy was triggered for signal amplification. The aptasensor showed a wide detection range and a low detection limit, indicating its reliability and potential in DON detection.