A Novel Competitive Aptamer Biosensor Based on Functional Nanomaterials for the Detection of Aflatoxin B ₁ (AFB ₁ ) in Rice and Corn

Developing a reliable detection method for aflatoxin B₁ (AFB₁) is urgent due to its potent hepatocarcinogenic effects. An electrochemical aptamer sensor based on competitive binding was prepared for the rapid detection of AFB₁ in this study. Poly(amideamine) dendrimers were electrodeposited onto a screen-printed gold electrode to enhance aptamer loading via amine group conjugation. The chemically synthesized gold nanostars can further improve electron transfer kinetics and provide additional binding sites for single-stranded DNA probes. Bioprobe and modified electrode were comprehensively characterized by transmission electron microscope, scanning electron microscopy, Zeta potential, energy dispersive spectroscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, and atomic force microscope. Differential pulse voltammetry (DPV) and square wave voltammetry (SWV) of pulse voltametric techniques were executed separately in AFB1 solutions for testing the performance of this prepared biosensor. Comparative analysis revealed that both methods exhibited a linear detection range of 10^-4 to 10³ ng/mL for AFB₁. Nevertheless, the DPV method achieved a lower limit of 2.25 × 10^-5 ng/mL than the SWV method, with a detection limit of 3.18 × 10^-5 ng/mL. Meanwhile, the developed biosensor showed excellent stability and reproducibility, establishing its reliability for AFB₁ quantification in complex matrices.