A controllable Y-shaped DNA structure assisted aptasensor for simultaneous detection of AFB1 and OTA based on ARGET ATRP

The development of a simple, rapid, and sensitive technology for the simultaneous detection of mycotoxins is of great significance in ensuring the safety of foods and drugs. Herein, a fluorescence aptasensor with high sensitivity and reproducibility for the simultaneous detection of aflatoxin B1 (AFB1) and ochratoxin A (OTA) was developed. In this sensing system, AFB1 and OTA aptamers were co-immobilized on the surface of magnetic beads (MBs) to form a Y-shaped structure through the principle of complementary base pairing, which were used as recognition probes to specifically capture the target. Activators generated by electron transfer for atom transfer radical polymerization (ARGET ATRP) was used as signal amplification strategy to improve the sensitivity. The initiator modified at the end of the antibody initiates the ARGET ATRP reaction. Different fluorescence signals were designed to achieve simultaneous detection of OTA and AFB1 with the limit of 18.62 and 1.60 fg/mL for AFB1 and OTA, respectively. In addition, experiments were conducted on three types of samples, and the recoveries of the two mycotoxins ranged from 87.30% to 109.50%, with relative standard deviations ranging from 0.50% to 4.92% under reproducible conditions. The results suggest that the developed aptasensor is sufficient to meet the different regulatory requirements of the two mycotoxins in food and drug safety and shows great potential.