Label-free fluorescent aptasensor based on exonuclease I for the determination of ochratoxin A

Abstract

Ochratoxin A (OTA) is a common foodmycotoxin that is widely distributed and highly toxic. The establishment of a sensitive, stable, and rapid OTA detection method is important to protect human health and food safety. In this study, a label-free aptamer fluorescent sensor was developed for the rapid determination of OTA by optimizing the concentration of fluorescent dyes, the addition of exonuclease I, and the reaction time. Under the optimal experimental conditions, the fluorescence intensity of SYBR Gold showed a linear relationship with the OTA concentration in the range of 5–500 ng/mL with a correlation coefficient of 0.9966 and a detection limit of 1.49 ng/mL, indicating good selectivity. The method was applied to determine OTA in red wine, with recovery rates ranging from 89.0% to 113.6% and relative standard deviations ranging from 4.3% to 6.2%. Compared with other aptamer-based OTA detection methods, the proposed method has higher sensitivity and selectivity and lower cost. Thus, the proposed method has good application prospects in OTA determination.