Impedimetric nanoimmunosensor platform for aflatoxin B1 detection in peanuts

This article developed a novel electrochemical immunosensor for the specific detection of aflatoxin B1 (AFB1). Amino-functionalized iron oxide nanoparticles (Fe3O4-NH2) were synthesized. Fe3O4-NH2 were chemically bound on self-assembly monolayers (SAMs) of mercaptobenzoic acid (MBA). Finally, polyclonal antibodies (pAb) were immobilized on Fe3O4-NH2-MBA. The sensor system was evaluated through atomic force microscopy (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). A reduction in the anodic and cathodic peak currents was observed after the assembly of the sensor platform. The charge transfer resistance (R-ct) was increased due to the electrically insulating bioconjugates. Then, the specific interaction between the sensor platform and AFB1 blocks the electron transfer of the [Fe(CN)(6)](3-/4-) redox pair. The nanoimmunosensor showed a linear response range estimated from 0.5 to 30 mu g/mL with a limit of detection (LOD) of 9.47 mu g/mL and a limit of quantification (LOQ) of 28.72 mu g/mL for AFB1 identification in a purified sample. In addition, a LOD of 3.79 mu g/mL, a LOQ of 11.48 mu g/mL, and a regression coefficient of 0.9891 were estimated for biodetection tests on peanut samples. The proposed immunosensor represents a simple alternative, successfully applied in detecting AFB1 in peanuts, and therefore, represents a valuable tool for ensuring food safety.