A fluorescent aptasensor for deoxynivalenol detection based on Nb.BbvCI-assisted targeted-responsive three-way junctions integrated DNA walking machine.

Deoxynivalenol (DON) contamination in cereals is a widespread issue with global implications, necessitating the development of efficient detection methods. Here, a fluorescent aptasensor integrating target-responsive DNA three-way junction (TWJ) and DNA walking machine was developed to detect DON. The DON-specific aptamer (Apt) and the walker (Walker DNA) are integrated into TWJs. TWJs initiate the DNA walking machine with the assistance of Nb.BbvCI to provide signal amplification for sensing events. The constructed fluorescent aptasensor selectively recognizes and detects DON. Additionally, the sensing platform explored the quantitative relationship between fluorescence signal changes and DON concentration, achieving a limit of detection (LOD) of 0.009 ng/mL. Ultimately, the method performed well in the detection of cornmeal samples with recoveries ranging from 95.49 % to 100.82 %. The method demonstrates good stability and is expected to be a potential candidate for the accurate detection of DON in grains.