Development of Ochratoxin A Aptasensor Based on Au Nanoparticles@g-C₃N₄

Ochratoxin is teratogenic, carcinogenic and immunotoxic to humans. It contains ochratoxin in many foods, so the detection of ochratoxin in food is particularly important. In this paper, gold nanoparticles (Au NPs)@g-C₃N₄ composite was synthesized by loading Au NPs on carbon nitride material, and it was immobilized on the surface of glassy carbon electrode by chitosan (Chit) as the substrate of electrochemical aptasensors. An ochratomycin A electrochemical aptasensor was constructed by hybridizing DNA1 and ochratoxin A (OTA) aptamers. The resulting hybrid strands were immobilized on the substrate of glassy carbon electrode. Electrochemical alternating current impedance (EIS) was used to detect the impedance value of the aptasensor when incubating different concentrations of OTA. The impedance value is inversely ratio to the concentration of OTA, achieving quantitative detection of OTA. The aptasensor can detect OTA with a linear range of 0.5-100 ng/mL, the linear correlation coefficient is 0.9506, and the detection limit is 0.167 ng/mL. This aptasensor provides a novel and efficient method for detecting OTA.