Simultaneous detection of patulin and ochratoxin A based on enhanced dual-color AuNCs modified aptamers in apple juice

Patulin (PAT) and ochratoxin A (OTA) are the two main mycotoxins present in apples. Herein, a sensitive aptasensor for simultaneous detection of PAT and ochratoxin OTA was developed. Dual-color gold nanoclusters (AuNCs) with enhanced fluorescence properties were synthesized and employed as fluorescence amplifiers. Two separated fluorescence peaks at 650 nm and 530 nm were monitored simultaneously by employing single excitation (405 nm), corresponding to the aptamer probes of Cys@BSA-AuNCs-AptPAT and Arg@ATT-AuNCs-AptOTA, respectively. The fluorescent aptasensor demonstrated satisfying specificity, storage ability and accuracy. Under the optimal experimental conditions, the linear detection range for PAT and OTA was 0.10-50 ng/mL, with the limit of detection of 0.09 ng/mL and 0.06 ng/mL, respectively. Most importantly, practicability of the constructed aptasensor were confirmed by conducting the determination of PAT and OTA in apple juice sample, indicating the great potential of the aptasensor in practical detection applications.