A sensitive biosensor for ochratoxin A detection based on triple-helix aptaswitch and bioorthogonal capture enabled signal amplification.

Ochratoxin A (OTA) has been classified as a possible human carcinogen and accurate monitoring of OTA is crucial for avoiding the contaminant risk. Herein, a sensitive biosensor for OTA detection was reported. This biosensor achieved a lower detection limit of 0.026 ng/mL with the linear range of 0.03-50 ng/mL, owning to the coordination of the structure-switching of the aptaswitch and bioorthogonal capture-based signal amplification of the functionalized paper. Finally it was applied in real samples precisely and a portable device was developed for the easy readout of the fluorescent signal. Notably, this approach possessed adequate simplicity with the thorough avoidance of fluorescence plate reader or complicated material modification steps for signal amplification, and it was universally applicable by replacing the aptamer sequence in the loop instead of redesigning the structure of triple-helix aptaswitch for multifarious target analytes. Taken together, we first combined the triple-helix aptaswitch and bioorthogonal capture-based signal amplification in the detection of OTA, and this novel detection method may offer a simple, cost-effective and sensitive sensing platform for agricultural products quality monitoring.