The characterization of adsorption of the amyloidogenic peptides, amyloid beta peptide 1-40 (Ab1-40), alpha-synuclein (a syn), beta-2-microglobulin (b2M) over nano-gold colloidal particle’s surfaces were investigated by using the pH dependent UV-Vis absorption spectroscopy. The amyloidogenic peptide generally support the unfolded conformation at pH 4 region and the folded conformation around pH 10. The peptide affinity of any sizes of gold colloid was confirmed to stably support a layer of peptide. The peptide placed over nano gold colloid still causes unfolding process at pH 4 leading to a networking with surrounding peptides coated over the nano-gold resulting in a formation of the aggregates of 1 mm size. However, there was no clear quantization of how much percent of the nano-surface is covered by peptide. We established a systematic scheme to extract the surface coverage ratio of peptide by using the pH dependent absorption peak shift. We discovered that critical pH (pHo) and an inverse of the curvature at pHo possessed a linear correlation. Since the larger pHo shift corresponds to the more coverage of peptide, we were able to characterize the surface coverage ratio of peptides for each size of gold colloidal particle. We are currently attempting to rationalize the most appropriate oligomer unit which corresponds to each coverage ratio. This oligomer unit can be associated with the key structure of an intermediate of fibrillogenesis.

Investigation of a nanoscale surface area coverage by a self assembly of amyloidogenic peptides

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.