Detection of aflatoxin B1 with a new label-free fluorescence aptasensor based on PVP-coated single-walled carbon nanohorns and SYBR Gold.

This paper describes a novel fluorescence label-free aptasensor to detect aflatoxin B1 (AFB1) by utilizing SYBR Gold, aptamer, and single-walled carbon nanohorns (SWCNHs). In the presence of AFB1, the conformation of AFB1-specific aptamer went through and the spatial structure of this specific aptamer was transformed accordingly. Due to the resistance of the transformed aptamer when adsorbed on the surface of SWCNHs, the protection of the fluorescence of SYBR Gold was accomplished. Consequently, concentrations of AFB1 showed a strong association with fluorescence intensity. The detection limit (LOD) of AFB1 was 1.89 ng/mL, while the linear range was 5-200 ng/mL and fluorescence intensity satisfactorily correlated (R2 = 0.9919) with the logarithm of AFB1 concentration.