A Label-free aptasensor based on Aptamer/NH2 Janus particles for ultrasensitive electrochemical detection of Ochratoxin A.

In this study, a novel aptasensor based on Aptamer/NH2 Janus particles is developed for the detection of Ochratoxin A(OTA). By coating gold on the hemispherical surface of the aminated polystyrene particles, Ochratoxin A aptamer is immobilized on the surface of the gold layer for selective identification and the other hemispherical able to bind to Glassy carbon electrode via peptide bond. Under optimum conditions, the sensor exhibited a wide dynamic range of OTA concentration from 1 × 10-5 nM to 10 nM, and the detection limit is 3.3 × 10-3 pM on condition of acceptable stability and reproducibility. The sensors were showed excellent performance in the detection of OTA in red wine sample with recoveries between 95.7% and 100.18%, which studied by the standard addition spiking technique. This work provides a new idea and method for preparing immune electrochemical sensors and is expected to be used for the OTA detection in red wine sample analysis.