제목

Detection of ochratoxin A(OTA) in coffee using chemiluminescence resonance energy transfer(CRET) aptasensor

요약

We report a chemiluminescence resonance energy transfer (CRET) aptasensor for the detection of ochratoxin A (OTA) in roasted coffee beans. The aptamer sequences used in this study are 5′-DNAzyme-Linker-OTA aptamer-3′-dabcyl. Dabcyl at the end of the OTA aptamer region plays as a quencher in CRET aptasensor. When hemin and OTA are added, the dabcyl-labeled OTA aptamer approaches to the G-quadruplex?hemin complex by formation of the G-quadruplex?OTA complex. The G-quadruplex?hemin complexes possess horseradish peroxidase (HRP)-like activity, and therefore, the HRP-mimicking DNAzyme (HRPzyme) catalyzes peroxidation in the presence of luminol and H₂O₂. Resonance energy transfer between luminol (donor) and dabcyl (acceptor) enables quenching of chemiluminescence signals. The signal decreases with increasing the concentration of OTA within the range of 0.1?100 ng mL^?1 (limit of detection 0.22 ng mL^?1), and the level of recovery of the respective 1 ng mL^?1 and 10 ng mL^?1 spiked coffee samples was 71.5% and 93.3%. These results demonstrated the potential of the proposed method for OTA analysis in diverse foods.