Hervás Pérez, Juan PabloSánchez-Paniagua López, Marta2026-04-142026-04-142025Hervás-Pérez JP, Sánchez-Paniagua M. Label-free electrochemical DNA biosensor for detection of peanut allergen Ara h2 based on gold nanoparticles-modified self-assembled monolayers in food matrices. Microchemical Journal 2025;219:116140. https://doi.org/10.1016/j.microc.2025.1161400026-265X10.1016/j.microc.2025.116140https://hdl.handle.net/20.500.14352/134717A label-free electrochemical genosensor for the detection of Ara h2, a major peanut allergen, has been developed using mixed self-assembled monolayers (SAMs) for DNA immobilization. The study used a sandwich format and compared gold nanoparticles-modified screen printed carbon electrodes (AuNPs-SPCE) and screen printed gold electrodes to obtain a highly sensitive bioplatform. Different binary and ternary SAMs were evaluated as sensing phase, by electrochemical impedance spectroscopy and cyclic voltammetry, obtained the best signal to noise ratio with CP-DTT-AuNPs-SPCE. The genosensor demonstrated a linear response in the concentration range of 0.025–10 nM, with a detection limit of 0.02 nM by square wave voltammetry. The precision of the biosensor was validated, showing a RSD of less than 8 % across different concentrations. Selectivity tests confirmed negligible signals for non-complementary sequences. Additionally, the method proved effective in real food matrices, with recovery rates between 95.0 % and 105.5 % in spiked soy-based beverage and low-fat cow’s milk.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/journal articlehttps://doi.org/10.1016/j.microc.2025.116140open access615:54615.31Peanut allergenSelf assembled monolayerGold nanoparticlesDNA biosensorElectrochemicaQuímica farmaceúticaTecnología farmaceútica2390 Química Farmacéutica