An aptamer based surface plasmon resonance biosensor for the detection of ochratoxin A in wine and peanut oil

• We developed an OTA aptamer-based surface plasmon resonance (SPR) biosensor.
• The biosensor was able to detect OTA in concentration range of 0.094–100 ng/mL with a lower detection limit of 0.005 ng/mL.
• The interaction between OTA and aptamer was screened in real time.
• The approach was successfully applied to detect OTA in wine and peanut oil samples.

Ochratoxin A (OTA), as a kind of chlorophenolic mycotoxin, exist widely in plant origin food and is harmful to human. Herein, a surface plasmon resonance (SPR) biosensor using an anti-OTA aptamer immobilized sensor chip was developed to measure ochratoxin A (OTA) quantificationally through a straightforward direct binding assay. The streptavidin protein as a crosslinker was immobilized onto the surface of a sensor chip and the biotin-aptamer was captured through streptavidin-biotin interaction. The biosensor exhibited a detection range from 0.094 to 100 ng/mL (linear range from 0.094 to 10 ng/mL) of OTA with a lower detection limit of 0.005 ng/mL. Detection of OTA in wine and peanut oil was further performed in the SPR biosensor using simple liquid–liquid extraction for sample pretreatments. Recoveries of ochratoxin A from spiked samples ranged from 86.9% to 116.5% and coefficients of variation (CVs) ranged from 0.2% to 6.9%. The developed methods in our studies showed good analytical performances with limits of detection much lower than the maximum residue limit, as well as a good reproducibility and stability.