Capacitive Biosensor for Glutathione Detection Based on Electropolymerized Molecularly Imprinted Polymer and Kinetic Investigation of the Recognition Process

Abstract

AbstractA novel capacitive biosensor based on electropolymerized molecularly imprinted polymer (MIP) for glutathione detection is reported. The capacitive sensor was prepared by electropolymerizing o‐phenylenediamine (o‐PD) on a self‐assembled 2‐mercaptoethane sulfonate (MES) monolayer modified gold electrode in the presence of template glutathione. 1‐Dodecanethiol was used to block the defect of polymer film to improve its dielectric performance. Hydrolization procedure was selected to remove the template thoroughly for better sensitivity. The dielectric property of the sensitive layer was characterized by differential pulse voltammetry (DPV). The linear response range of the sensor for glutathione was between 0.025 and 0.30 mmol L−1 with a detection limit of 1.25×10−3 mmol L−1. Satisfactory results were obtained in the direct detection of real samples. The selectivity was evaluated by capacitance selective coefficient of glutathione and other compounds. The kinetic aspects of the recognition process were investigated by capacitive transduction. A two‐step kinetic model was derived to describe the interaction between analyte and imprint sites. Fitted results were well in agreement with the corresponding experimental results.