A Simple Ratiometric Electrochemical Aptasensor Based on the Thionine–Graphene Nanocomposite for Ultrasensitive Detection of Aflatoxin B2 in Peanut and Peanut Oil
Fan Jia,
Yuye Li,
Qingfa Gong,
Dong Liu,
Shuyun Meng,
Chengxi Zhu,
Tianyan You
Affiliations
Fan Jia
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
Yuye Li
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
Qingfa Gong
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
Dong Liu
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
Shuyun Meng
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
Chengxi Zhu
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
Tianyan You
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
The accurate and reliable analysis of aflatoxin B2 (AFB2) is widely required in food and agricultural industries. In the present work, we report the first use of a ratiometric electrochemical aptasensor for AFB2 detection with high selectivity and reliability. The working principle relies on the conformation change of the aptamer induced by its specific recognition of AFB2 to vary the ratiometric signal. Based on this principle, the proposed aptasensor collects currents generated by thionine–graphene composites (ITHI) and ferrocene-labeled aptamers (IFc) to output the ratiometric signal of ITHI/IFc. In analysis, the value of ITHI remained stable while that of IFc increased with higher AFB2 concentration, thus offering a “signal-off” aptasensor by using ITHI/IFc as a yardstick. The fabricated aptasensor showed a linear range of 0.001–10 ng mL−1 with a detection limit of 0.19 pg mL−1 for AFB2 detection. Furthermore, its applicability was validated by using it to detect AFB2 in peanut and peanut oil samples with high rates of recovery. The developed ratiometric aptasensor shows the merits of simple fabrication and high accuracy, and it can be extended to detect other mycotoxins in agricultural products.
