Charged surfactants induce a non-fibrillar aggregation pathway of amyloid-beta peptide.

The amyloid β-peptide with a sequence of 42 amino acids is the major constituent of extracellular amyloid deposits in Alzheimer's disease plaques. The control of the peptide self-assembly is difficult to achieve because the process is fast and is affected by many variables. In this paper, we describe the effect of different charged and non-charged surfactants on Aβ(₁₋₄₂) fibrillation to define common alternate aggregation pathways. The characterization of the peptide-surfactant interactions by ultra-structural analysis, thioflavin T assay and secondary structure analysis, suggested that charged surfactants interact with Aβ(₁₋₄₂) through electrostatic interactions. Charged micelles slow down the aggregation process and stabilize the peptide in the oligomeric state, whereas non-charged surfactants promote the Aβ(₁₋₄₂) fibril formation.