Chiral Shell Core-Satellite Nanostructures for Ultrasensitive Detection of Mycotoxin.

Herein, the design of a DNA-based chiral biosensor is described utilizing the self-assembly of shell core-gold (Au) satellite nanostructures for the detection of mycotoxin, ochratoxin A (OTA). The assembly of core-satellite nanostructures based on OTA-aptamer binding exhibits a strong chiral signal with an intense circular dichroism (CD) peak. The integrity of the assembly of core-satellite nanostructures is limited to some extent in the presence of different levels of OTA. Correspondingly, the chiral intensity of assembly is weakened with increasing OTA concentrations, allowing quantitative determination of the target. The developed chiral sensor shows an excellent linear relationship between the CD signal and concentrations of OTA in the range of 0.1-5 pg mL-1 with a limit of detection as low as 0.037 pg mL-1 . The effectiveness of the biosensor in a sample of red wine is verified and a good recovery rate is obtained. These results suggest that the strategy has great potential for practical application.