Smart electrochemical immunosensing of aflatoxin B1 based on a palladium nanoparticle-boron nitride-coated carbon felt electrode for the wine industry

Abstract: This study describes the fabrication of an aflatoxin (AFB₁) electrochemical immunosensor by immobilization of an anti-AFB₁ antibody-bovine serum albumin (BSA) conjugate on a layer of L-cysteine (L-Cys) used to link the antibody to the palladium nanoparticle-boron nitride (PdNP-BN)-modified carbon felt (CF) electrode. Each step of the immunosensor fabrication was characterized using cyclic voltammetry (CV) and electrochemical imped- ance spectroscopy (EIS). These two analyses demonstrated that BN acted as a substrate for PdNPs and also as an electroactive material that enhanced the immunosensor electrical conductivity. Different features (antibody concentration, pH, incubation time) were optimized to enhance the immunosensor analytical performance. In these conditions, the fabricated immunosensor displayed a large linear range (1–10 ng mL⁻¹; R² = 0.9987), low limit of detection (0.834 ng mL⁻ ¹ AFB₁), and was stable for up to 3 weeks. The fabricated electrochemical immunosensor could detect AFB₁ in wine samples with recovery levels of 93–106%. Lastly, the Monte Carlo simulation studies confirmed the stronger binding of the anti-AFB₁ antibody-BSA conjugate to the L-Cys/PdNP- BN/CF electrode surface, and molecular docking confirmed the docking of BSA subdomain II to the anti-AFB₁ antibody.