Preparation of Deoxynivalenol Complete Antigen and Its Application in Microchannel Resistance Immune Sensing Platform with Electrical Signal Analysis

Two coupling methods, dicyclohexylcarbodiimide (DCC) and carbonyldiimidazole (CDI), are designed to prepare the complete antigen of deoxynivalenol (DON). The synthesized complete antigen is identified using high-performance liquid chromatography (HPLC), ultraviolet spectrophotometry (UV), and sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). The complete antigen (DON-BSA) and antibody (DON-Ab) are then covalently coupled to carboxylated polystyrene (PS) microspheres to prepare PS-DON-BSA and PS-Ab. A new method for detecting DON is developed by constructing a microchannel resistance immunosensor (MCRS) based on the competitive bio-recognition reaction between these components and DON. The change of current value caused by the change of resistance in the detection platform can realize DON concentration. The results showed that the UV spectra of the complete antigens prepared by the two methods are significantly different from those of the hapten and carrier protein, with measured coupling ratios of approximately 9.8:1 and 7.8:1, respectively. SDS-PAGE also indicates good coupling effects. When the complete antigen is applied to the self-developed DON detection platform, this method shows a good linear relationship in the range of 100 pg/mL to 1000 ng/mL, with a correlation coefficient of 0.991, a detection limit of 499 pg/mL, a recovery rate of 89.26 to 108.50%, and a relative standard deviation of 4.15 to 6.57%, which meets the requirements for DON analysis and samples detection.