A Novel Competitive Aptamer Biosensor Based on Functional Nanomaterials for the Detection of Aflatoxin B1 (AFB1) in Rice and Corn

Developing a reliable detection method for aflatoxin B 1 (AFB 1 ) is urgent due to its potent hepatocarcinogenic effects. An electrochemical aptamer sensor based on competitive binding was prepared for the rapid detection of AFB 1 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 10 3 ng/mL for AFB 1 . 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 AFB 1 quantification in complex matrices. Graphical The addition of aflatoxin B1 (AFB1) causes competitive binding, leading to the detachment of the probe AuNs@ssDNA from the AuNs@ssDNA/Aptamer/PAMAM/SPGE sensing platform, thereby altering the electron transfer rate on the electrode surface. The attenuation current of the [Fe(CN)6] 3 -/ 4 - redox signal is monitored via differential pulse voltammetry and square wave voltammetry, enabling the quantitative determination of AFB1.