Polyaniline-based molecularly imprinted polymer biosensor for sensitive and selective detection of aflatoxin B1

Aflatoxin B1 (AFB1), a Group 1 carcinogen, remains a major threat to food safety, creating an urgent need for rapid, sensitive, and reliable detection methods. In this study, we present a polyaniline-based molecularly imprinted polymer (MIP) electrochemical biosensor designed for the selective detection of AFB1. The MIP was synthesised using AFB1 as a template and deposited onto gold-coated tungsten electrodes with the aid of polyethyleneimine and carbon nanotubes (CNTs) to improve surface functionality and conductivity. Comprehensive characterisation by FTIR, 1H NMR, DSC, and SEM confirmed efficient template removal, uniform polymer coating, and the formation of well-defined selective binding sites. Electrochemical impedance spectroscopy revealed a clear exponential decrease in impedance with increasing AFB1 concentration, achieving a limit of detection of 3.91 ppb over a linear range of 0.1–20 ppb, with a strong correlation coefficient (R² = 0.9811). Selectivity experiments using colchicine as a competing analyte showed negligible interference, demonstrating the specificity of the imprinted cavities. The incorporation of CNTs significantly reduced electrode resistance, leading to enhanced signal sensitivity. In addition to analytical performance, the environmental impact of the MIP material was evaluated using Caenorhabditis elegans, where exposure resulted in approximately a 50% reduction in survival by day 12 along with decreased locomotor activity. These findings highlight both the effectiveness of the proposed antibody-free biosensing platform for AFB1 detection and the importance of considering environmental safety in the development of polymer-based sensor materials.