Aptamers Adsorbed on WSe₂ Nanosheets in a Label-Free Colorimetric Aptasensor for Ochratoxin A

Abstract

Ochratoxin A (OTA) poses a great threat to human health, and its rapid detection has drawn wide concerns in agrifood product risk assessment. Herein, on the basis of the aptamerenhanced peroxidase-mimetic property of two-dimensional fewlayer tungsten diselenide (WSe 2 ) nanosheets, a simple label-free colorimetric aptasensor is presented for OTA detection. The enzymatic mimic property of the WSe 2 nanosheets could be enhanced through aptamer adsorption because of the enhanced affinity of WSe 2 nanosheets to 3,3′,5,5′-tetramethylbenzidine. A good linear relationship was obtained in the range from 0.5 to 50 ng/mL, and the limit of detection for OTA was 0.16 ng/mL. The performance of this strategy was comparable to previous strategies for OTA determination. Further, this colorimetric aptasensor displayed satisfying specificity and stability in a complex food matrix including both red wine and wheat flour samples. Hence, the results of this study suggest potential applications of the aptasensor to detect mycotoxins in different agri-food products.