Interaction of A?(1-40) with Supported Planar Lipid Bilayers Containing GM1 Using Electrochemical Methods

Amyloid-b (Ab) peptides are important and reliable molecular biomarkers for the diagnosis and prognosis of Alzheimer's disease. Aggregation and fibrillation of Ab peptides on ganglioside GM1 (GM1)-containing lipid membranes is considered a cause of neurodegenerative disease. Because GM1 is abundant in the central nervous system and plays a key role in the aggregation of Ab, the interaction of Ab with supported planar lipid bilayers (SPBs) containing GM1 is of great significance. We prepared SPBs containing GM1 in order to study the electrochemical characteristics of GM1/sphingomyelin/cholesterol SPBs and their interaction with Ab(1-40) by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results suggested that SPBs formed an insulating layer on the surface of the electrode and were damaged by Ab(1-40), thereby reducing the resistance of SPBs and enhancing the capacity and rate of ion transport. The results obtained from EIS correlated well with Thioflavin T fluorescence and atomic force microscopy, which proved that EIS is a promising method for analyzing the interaction between Ab peptides and lipid membranes.