A Non-label Electrochemical Aptasensor Based on Cu Metal-Organic Framework to Measure Aflatoxin B1 in Wheat Flour

Aflatoxin B1 (AFB(1)) is an important indicator in food safety assessment. In the present study, a non-label electrochemical aptasensor based on the Cu metal-organic framework (CuMOF) was fabricated to measure AFB(1). The CuMOF was synthesized with a simple method and used to modify glassy carbon electrode (GCE). The field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) methods were used to describe the morphology, structure, and size of the CuMOF. It is established that the CuMOF with a large surface area played an important role as a unique substrate to immobilize AFB(1) aptamer. The fabricating stages of the aptasensor were followed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using ferri/ferrocyanide as a redox probe. The results indicate that under optimal conditions, the aptamer-AFB(1) interaction increases the resistance to electron transfer between them. Through an EIS method, the linear range of 1.0 x 10(-3) to 200.0 ng/mL and detection limit of 8.3 x 10(-4) ng/mL were obtained for quantitative determination of AFB(1) at the aptasensor surface. In addition, the proposed aptasensor has acceptable reproducibility, repeatability, and stability to determine AFB(1). Finally, this method has been successfully used for the analysis of AFB(1) in wheat flour samples.