Cas12a-CHA dual-amplified fluorescent aptasensor for sensitive detection of ochratoxin A.

Ochratoxin A (OTA), a mycotoxin commonly found in food products, poses significant health risks due to its carcinogenic and immunotoxic properties. The development of sensitive and specific detection methods for OTA is therefore essential. In this study, we developed a fluorescence aptasensor for sensitive and selective detection of OTA in complex food matrices. The aptasensor integrates the specificity of aptamer, the signal amplification capability of catalytic hairpin assembly (CHA), and the trans-cleavage activity of Cas12a. Benefiting from the synergistic effect of the aptamer, CHA, and Cas12a, the proposed aptasensor achieved a detection limit of 0.1 ng/mL with a linear range of 1.0-25.0 ng/mL (R = 0.99) and exhibited high selectivity against non-target mycotoxins. Additionally, it showed a good recovery rate of 90.7 %-96.0 % for spiked beer samples, with a relative standard deviation (RSD) of less than 3.0, indicating excellent precision and minimal background interference. These results demonstrated that the proposed aptasensor is a promising tool for food safety monitoring.