Electrochemical impedance spectroscopy-based characterization of donepezil-bovine serum albumin interaction at the electrode interface.

Protein-drug interactions are one of the fundamental processes determining the biological effects of drugs, and they mostly occur via weak interactions such as van der Waals forces, hydrogen bonds, and ionic bonds. In this study, the binding interaction between Donepezil (DPZ) and Bovine Serum Albumin (BSA) was investigated using Electrochemical Impedance Spectroscopy (EIS), a sensitive and rapid method, and the interfacial changes resulting from drug-protein complex formation were evaluated by monitoring the charge transfer resistance (RCT). Given the limited number of studies in the literature that utilize the EIS method, this study has the potential to fill a significant gap in protein-drug interaction research. This study developed a simple, label-free, electrochemical impedance spectroscopy-based approach that allows direct measurement in solution. Using a Pencil Graphite Electrode (PGE), binding was characterized through changes in charge transfer resistance in a system containing DPZ and BSA. Responses related to interaction with BSA were recorded at increasing DPZ concentrations by optimizing pH and incubation time. The findings demonstrate that impedance measurements are an effective method for directly and accurately monitoring drug-protein interactions. Furthermore, the findings obtained for the DPZ-BSA interaction using RCT were confirmed by UV-Vis spectrophotometry and Isothermal Titration Calorimetry (ITC).