DNAzyme-driven tripedal DNA walker for ratiometric electrochemical aptasensor ultrasensitive detection of aflatoxin B1

Abstract

Aflatoxin B1 is a potent carcinogen widely found in agricultural products and feed. Therefore, investigating the development of convenient, sensitive, and precise techniques for detecting AFB1 is critical. This work proposes a ratiometric electrochemical aptasensor based on DNAzyme-driven tripedal DNA walker for enzyme-free AFB1 detection. The design of multiple legs reduces the moving time on the electrode surface and enhances the value of signal response. In this approach, the tagging of ferrocene and methylene blue as signal switch molecules diminishes the impact of interferences and significantly enhances the reproducibility (RSD: 2.825%). Meanwhile, the tripedal DNA walker and DNAzyme dual signal amplification enabled the sensor to detect AFB1 traces in cereals.We achieved trace detection of AFB1 with a detection limit of 61 fg/mL and a wide linear range from 0.0001 to 10 ng/mL. Furthermore, the aptasensor success rate was comparable to that of HPLC-PMP. The results demonstrate enormous potential for detection. Furthermore, the method can detect various targets by altering the target aptamer, displaying attractive scalability. This suggests its tremendous prospective in detecting mycotoxins in food in the future.