Magnetic beads-based double-stranded DNA fluorescent aptasensor biosensor for deoxynivalenol detection.

Deoxynivalenol (DON) is one of the most harmful mycotoxins that poses great health threats to human and animals. Herein, a simple and sensitive magnetic beads-based fluorescent biosensor was successfully prepared for detection of DON in cereals. A stable double-stranded DNA (dsDNA, biotin-sDNA+FAM-cDNA/AP) was formed on the surface of streptavidin-coated magnetic beads (SMBs). DON could specifically bind to aptamer probe (AP), thereby releasing cDNA labeled with 6-carboxyfluorescein (FAM) (FAM-cDNA). After magnetic separation, the amount of FAM-cDNA was analyzed to achieve the detection of DON. Under the optimal conditions, the established aptasensor displayed excellent performance for DON analysis with the nice linear relationship (R = 0.9972) in the range of 0.1-50 ng/mL, high sensitivity (detection limit of 0.033 ng/mL) and selectivity. The total analysis time including samples preparation was around 200 min. The designed sensor was validated by determining the recoveries (95.48-112.48 %) in real paddy, wheat and maize samples, and its applicability to them was also verified by super-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The current study proposed a promising strategy for DON detection, and could easily be extended for the analysis of other targets through the rational design of the sequences of aptamer probe and cDNA.