Nanoelectrical characterization of amyloid-β 42 aggregates via Kelvin probe force microscopy

Wonseok Lee, Hyungbeen Lee, Yeseong Choi, Kyo Seon Hwang, Sang Woo Lee, Gyudo Lee, Dae Sung Yoon

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Biological processes related to amyloid-β (Aβ) aggregation and deposition are associated with the onset of Alzheimer’s disease. Although these processes are attributed to electrostatic interactions between the Aβ42 sequences, the electrical properties of Aβ aggregates (i.e., oligomers and fibrils) have not yet been fully explored despite their importance. Here, we investigated the nanoelectrical properties (i.e., surface potential) of Aβ42 aggregates using Kelvin probe force microscopy (KPFM) and found that the surface potential of the Aβ42 aggregates was changed from positive to negative with pH, passing across zero surface potential at pH=5.2-5.4. The measured surface potentials were ranged from 48 to -35 mV/nm for both the oligomers and the fibrils. From our observations, we determined the isoelectric points (pIs) of both cases. Using the commercial software PyMOL, we also converted the surface potential of a single monomorphic Aβ42 fibril; in the simulation, we calculated the net charges of the monomorphic fibrils depending on pH, predicted its pI by Boltzmann curve fitting, and compared these results with our experimental KPFM data.

Original languageEnglish
Pages (from-to)1187-1191
Number of pages5
JournalMacromolecular Research
Volume25
Issue number12
DOIs
Publication statusPublished - 2017 Dec 1

Keywords

  • amyloid fibril
  • amyloid-Aβ
  • computer simulation
  • kelvin probe force microscopy
  • surface potential

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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