Development of a CRISPR/Cas12a-assisted fluorescent aptasensor for simultaneous detection of zearalenone and ochratoxin A

Mycotoxins, such as zearalenone (ZEN) and ochratoxin A (OTA), represent significant hazards to both human and animal health, necessitating strict monitoring and regulation of mycotoxin levels in food, feed, and environment. In this study, a simple and efficient CRISPR/Cas12a-assisted fluorescent aptasensor is presented for the simultaneous detection of ZEN and OTA. Utilizing a Bifunctional aptamer (B-APT), this biosensor achieves dual recognition of the both targets, subsequently converting their concentrations into observable fluorescent signals through the Cas12a/crRNA cis-cleavage activity. Rational modifications of the complementary strands specific to the two targets enable distinct emission wavelengths under the same excitation light, facilitating simultaneous and independent quantitative determination of ZEN and OTA. Under optimized conditions, the CRISPR/Cas12a-aptasensor demonstrates robust detection capabilities for individual ZEN and OTA targets, as well as their mixture, yielding consistent standard curves. This methodology exhibits reliable detection of ZEN and OTA concentrations spanning from 0.25 nM to 256 nM and 1 nM to 1024 nM, with respective limit of detection (LOD) values of 190 pM and 931 pM. Furthermore, this method showcases exceptional selectivity and considerable recovery rates (89.17 %–109.88 % for ZEN and 101.19 %–106.51 % for OTA) in corn oil samples, underscoring its efficacy as an advanced tool for ZEN and OTA detection and offering valuable insights into the simultaneous detection of diverse targets.