Simultaneous Detection of Ochratoxin A and Aflatoxin B1 Based on Stable Tuning Fork-shaped DNA Fluorescent Aptasensor.

Abstract

Tuning fork, consisting of two fork arms and a fork handle, has a stable and rigid structure. Inspired by this structure, a tuning fork-shaped DNA (TF-DNA) fluorescence aptasensor was constructed to detect ochratoxin A (OTA) and aflatoxin B1 (AFB1). A TF-DNA double-stranded structure capable of attaching both OTA aptamer labeled with the FAM fluorescent group (FAM-Apt) and AFB1 aptamer labeled with the ROX fluorescent group (ROX-Apt) was designed and linked to magnetic beads. This TF-DNA double-stranded structure can provide a stable platform for dual-target detection. In the presence of OTA and AFB1, FAM-Apt and ROX-Apt preferentially bound to them and detached from the TF-DNA double-stranded structure. Dual-signal fluorescent probes were collected from the supernatant by magnetic separation, and achieved fluorescence enhancement at 520nm and 607nm, respectively. The linear ranges are 0.05ng/mL to 100ng/mL for OTA and 0.1ng/mL to 100ng/mL for AFB1, and the detection limits are 0.015ng/mL and 0.045ng/mL, respectively. The developed sensor has the advantages of simple and fast preparation, good specificity and reproducibility, which is promising for the simultaneous determination of multiple hazardous substances in food.