Tri-mode fluorescence/colorimetric/strip aptasensor with CRISPR/Cas12a-driven cascade strategy for mycotoxin

Multi-mode biosensors are promising rapid detection methods for mycotoxins, while these methods are still challenging in practice due to accessibility and efficiency. A tri-mode aptasensor platform based on CRISPR/Cas12a-driven cascade strategy is presented for ultrasensitive quantification of ochratoxin A (OTA) in this study. The probes of Apt@cDNA, fluorophore-quencher (FQ-reporter) and glucose oxidase (GOx)-reporter were prepared in advance to provide specific recognition and efficient signaling conversion. When target of OTA presented, the released cDNA aroused CHA reaction and then activated CRISPR/Cas12a, which not only used to turn-on the FQ-reporter but also release the GOx. To further improve the performance, the glucose was selected to generate numerous H₂O₂ molecules. The ultrasensitivity had been exhibited with limit of detection (LOD) values of 23.7 pg mL^-1, 9.10 pg mL^-1 and 16.9 pg mL^-1 for fluorescence, colorimetric and strip mode, respectively. The tri-mode aptasensor demonstrated satisfactory specificity, accuracy, and practicability by its application in spiked and real samples. Furthermore, the highlights, including quantitative capability, homogeneous reaction, and simplified operation, had been integrated. This proposed aptasensor has provided an ultrasensitive tri-mode rapid detection platform through CRISPR/Cas12a-driven generalduty optical signals, which might have promising prospects in the harmful substance monitoring in various scenarios.