Ultrasensitive and label-free electrochemical aptasensor based on carbon dots-black phosphorus nanohybrid for the detection of Ochratoxins A

Abstract In this work, we have synthesized the novel carbon dots-black phosphorus nanohybrid (CDs-BP). And a novel label-free electrochemical aptasensor based on CDs-BP was constructed for ultrasensitive detection of Ochratoxins A (OTA). The morphology and structure of nanocomposite were analyzed by transmission electron microscope, X-ray photoelectron spectroscopy, Zeta potential, et al. The CDs-BP nanohybrid, an excellent carrier for the immobilization of aptamer (Apta), was prepared through C-P bond, resulting in the enhancement of the electrochemical sensing performance for OTA detection. The results showed that the aptasensor had a wide linear range towards OTA (0.1 fg/mL - 10.0 ng/mL) with a low detection limit of 0.03 fg/mL under the optimal conditions. The proposed aptasensor displayed good electrochemical stability and excellent selectivity to OTA detection. Moreover, a satisfactory practical application results were obtained for different actual samples of wheat and grape juice samples. Thus, a new aptasensor was raised based on the CDs-BP nanocompound for the electrochemical detection of contaminants in edible agricultural food.