Effect of surfaces on amyloid fibril formation.
Using atomic force microscopy (AFM) we investigated the interaction of amyloid beta (Aβ) peptide with chemically modified surfaces in order to better understand the mechanism of amyloid toxicity, which involves interaction of amyloid with cell membrane surfaces. We compared the structure and density of Aβ fibrils on positively and negatively charged as well as hydrophobic chemically-modified surfaces at physiologically relevant conditions. We report that due to the complex distribution of charge and hydrophobicity amyloid oligomers bind to all types of surfaces investigated (CH₃, COOH, and NH₂) although the charge and hydrophobicity of surfaces affected the structure and size of amyloid deposits as well as surface coverage. Hydrophobic surfaces promote formation of spherical amorphous clusters, while charged surfaces promote protofibril formation. We used the nonlinear Poisson-Boltzmann equation (PBE) approach to analyze the electrostatic interactions of amyloid monomers and oligomers with modified surfaces to complement our AFM data.
Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada.
Bradley
B
Moores
Elizabeth
E
Drolle
Simon J
SJ
Attwood
Janet
J
Simons
Zoya
Z
Leonenko
D016229:Amyloid beta-Peptides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D018625:Microscopy, Atomic Force; D010446:Peptide Fragments / Q000737:chemistry*; D016012:Poisson Distribution; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D012996:Solutions; D055672:Static Electricity; D013499:Surface Properties; D013696:Temperature
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D012996:Solutions; C075222:amyloid beta-protein (1-42)