Immunoaffinity biosensors for deoxynivalenol determination from wheat sample: the evaluation of antibody immobilization route and surface topography on the sensor performance

Deoxynivalenol (DON) is one of the most common mycotoxins found in food and feed. This study aims to address the growing need for sensing platforms by applying surface engineering for the high-sensitivity detection of DON. Antibody immobilization via a self-assembled monolayer (SAM) strategy was systematically compared with immobilization on a porous poly(glycidyl methacrylate) [poly(GMA)] surface. The developed surfaces were characterized using Fourier transform infrared spectroscopy - attenuated total reflection (FTIR-ATR), atomic force microscopy (AFM), contact angle (CA) measurements, cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The results confirmed successful surface modification and demonstrated that surface functionalization plays a critical role in sensor performance and signal transduction. DON in standard solutions was determined using the developed AuSPE/Cys@antiDON and AuSPE/poly(GMA)@antiDON sensor platforms, with a linear working range of 2-20 ng/mL. The limit of detection (LOD) and limit of quantification (LOQ) for standard solutions were 1.43-4.33 ng/mL for AuSPE/Cys@antiDON and 1.67-5.07 ng/mL for AuSPE/poly(GMA)@antiDON, respectively. The recovery values obtained for the wheat sample were 103.72% and 99.76%, respectively. The developed sensor exhibited high selectivity, sensitivity, and repeatability performance for DON determination in both standard solutions and wheat matrix.