Abstract
The understanding of the interaction between the membrane of neurons and amyloid-beta peptides is of crucial importance to shed light on the mechanism of toxicity in Alzheimer's disease. This paper describes how supercritical angle fluorescence spectroscopy was applied to monitor in real-time the interaction between a supported lipid bilayer (SLB) and the peptide. Different forms of amyloid-beta (40 and 42 amino acids composition) were tested, and the interfacial fluorescence was measured to get information about the lipid integrity and mobility. The results show a concentration-dependent damaging process of the lipid bilayer. Prolonged interaction with the peptide up to 48 h lead to an extraction and clustering of lipid molecules from the surface and a potential disruption of the bilayer, correlated with the formation of peptide aggregates. The natural diffusion of the lipid was slightly hindered by the interaction with amyloid-beta(1-42) and closely related to the oligomerization of the peptide. The adsorption and desorption of Amyloid-beta was also characterized in terms of affinity. Amyloid-beta(1-42) exhibited a slightly higher affinity than amyloid-beta(1-40). The former was also more prone to aggregate and to adsorb on the bilayer as oligomer.
Dubois, Valentin