Ultrasensitive electrochemical aptasensing of aflatoxin B1 using CuO nanoparticle-functionalized 3D reduced graphene oxide nanocomposites

This work presents an electrochemical aptasensor for the measurement of aflatoxin B1 (AFB1). The sensing platform was constructed by immobilizing an AFB1-specific aptamer on a three-dimensional reduced graphene oxide (3DrGO) decorated with copper oxide (CuO) nanoparticles. The nanocomposite provides high conductivity and an extensive surface area for immobilizing the AFB1-specific aptamer. Monitoring of the aptasensor preparation process was performed using the electrochemical impedance spectroscopy (EIS) method. The analytical signal for quantifying AFB1 is derived from the change in the differential pulse voltammetry (DPV) peak current of Cu in CuONPs, measured before and after incubation of the aptamer with the AFB1. The developed aptasensor exhibited a broad linear concentration range from 1.0 × 10 −3 ng mL −1 to 200.0 ng mL −1 , with a low detection limit of 0.37 pg mL −1 as measured by the DPV technique. The aptasensor demonstrated high selectivity, stability, and reproducibility, and was successfully used to measure AFB1 in wheat flour samples. This work underlines the potential of CuO-3DrGO nanocomposites as an efficient substrate for the measurement of mycotoxins in food safety applications. • A label-free electrochemical aptasensor was developed for the rapid detection of Aflatoxin B₁ (AFB₁). • A CuO nanoparticle–decorated 3D reduced graphene oxide (CuO–3DrGO) nanocomposite served as the sensing substrate. • The change in CuO oxidation peak current (DPV) was used as the analytical signal. • The sensor exhibited excellent selectivity and reproducibility and was successfully applied to wheat flour samples.