A comparative study on the self-assembly of an amyloid-like peptide at water-solid interfaces and in bulk solutions

In the past years the self-assembly of amyloid-like peptides has attracted increasing attentions, because it is highly related to neurodegenerative diseases and has a potential for serving as nanomaterial to fabricate novel and useful nanostructures. In this paper, we focused on the role of interfacial conditions in the self-assembly of an amyloid-like peptide, termed Pep11. It was found that, when dissolved in bulk solutions, Pep11 formed into β-sheet structures and assembled into long filaments in several hours, as revealed by Thioflavin T fluorescence and transmission electron microscopy (TEM) morphology characterization, respectively. When the peptide solution was added onto a mica/HOPG substrate, peptide filaments with three preferred orientations with an angle of 60° to each other were formed immediately, as imaged in situ by atomic force microscopy (AFM). However, the kinetics in filament formation and the morphologies of the formed beta sheet either on HOPG and mica or in bulk solutions were quite different. These results indicate that the interfacial properties dramatically affect the peptide self-assembly process.