Nuclease Triggered "Signal-On" and Amplified Fluorescent Sensing of Fumonisin B Incorporating Graphene Oxide and Specific Aptamer.

Remarkable advancements have been achieved in the development of rapid analytic techniques toward fumonisin B (FB) monitoring and even trace levels for food safety in recent years. However, the point-of-care testing for quantitative and accurate FB determination is still challenging. Herein, an innovative aptasensor was established to monitor FB by utilizing graphene oxide (GO) and nuclease-triggered signal enhancement. GO can be utilized as a fluorescence quenching agent toward a fluorophore-modified aptamer, and even as a protectant of the aptamer from nuclease cleavage for subsequent target cycling and signal amplification detection. This proposed sensing strategy exhibited a good linearity for FB determination in the dynamic range from 0.5 to 20 ng mL with a good correlation of R = 0.995. Its limit of detection was established at 0.15 ng mL (S/N = 3), which was significantly lower than the legal requirements by three orders of magnitude. The interferent study demonstrated that the introduced aptasensor possessed high selectivity for FB. Moreover, the aptasensor was successfully applied to the detection of wheat flour samples, and the results were consistent with the classical ELISA method. The rapid response, sensitive and selective analysis, and reliable results of this sensing platform offer a promising opportunity for food mycotoxin control in point-of-care testing.