DNA tetrahedral scaffold based one-step ratiometric electrochemical detection of aflatoxin B1 in tobacco samples

To effectively monitor Aflatoxin B1 (AFB 1 ) in tobacco samples, a ratiometric electrochemical biosensor based on DNA tetrahedral scaffold (DTS) and AuNPs/chitosan (CS) modified electrode has been successfully fabricated. The ultra-thin AuNPs not only present a larger specific sensing surface, but also can graft more DTS onto the surface of the electrode. The DTS is directly grated with two strands of AFB 1 aptamer, which leading to a facile one-step detection of AFB 1 . In the presence of AFB 1 , the current of methylene blue (MB) keeps stable, while the current of ferrocene (Fc) decreases since the target takes away the Fc-labeled aptamer from the electrode surface. The fabricated biosensor can monitor AFB 1 in the linear range of 0.01–1000 pg·mL −1 with the detection limit of (LOD) 2.6 fg·mL −1 . More importantly, the biosensor performs well in the detection of AFB1 in tobacco samples with the LOD of 2.86 fg·mL −1 . The developed ratiometric electrochemical biosensor displays high selectivity, good stability and high potential in tobacco sample’s AFB 1 detection.