Electrochemical aptasensor based on exonuclease III-mediated signal amplification for sensitive detection of vomitoxin in cornmeal
Kai Wang, Yan Han, Baoshan He, Lingling Xie, Renli Liu, Min Wei, Huali Jin, Wenjie Ren, Zhiguang Suo, Yiwei Xu
Abstract
Vomitoxin (DON) residues in grains are of great concern to public health. Herein, a label-free aptasensor was constructed 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 cycling 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 × 10 −8 mg·mL −1 to 5 × 10 −4 mg·mL −1 for DON, and the detection limit was 1.79 × 10 −9 mg·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.