title: Study of amyloid β-peptide (Aβ12-28-Cys) interactions with Congo red and β-sheet breaker peptides using electrochemical impedance spectroscopy.
abstract: A surface-based approach is presented to study the interactions of Aβ12-28-Cys assembled on gold surfaces with Congo red (CR) and a β-sheet breaker (BSB) peptide. The various aspects of the peptide film have been examined using different electrochemical and surface analytical techniques. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) results using redox probes [Fe(CN)(6)](3-/4-) show that Aβ12-28-Cys on gold forms a stable and reproducible blocking film. EIS analysis shows that CR and BSB have different effects on the electrochemical properties of Aβ12-28-Cys films, presumably due to changes in the interactions between the film and CR and BSB. EIS results indicate that in the case of CR film resistance decreases significantly presumably due to better penetration of the solution-based redox probe into the film, whereas in the case of BSB, the film resistance increases. We interpret this difference to BSB being able to interact with the Aβ12-28-Cys on the surface and presumably forming a film that presents a higher resistance for electron transfer from the redox probe to the solution.
authors.affiliation: Department of Chemistry, The University of Western Ontario, 1151 Richmond Street North, London, Ontario N6A 5B7, Canada.
authors.forename: Raheleh
authors.initials: R
authors.lastname: Partovi-Nia
authors.forename: Samaneh
authors.initials: S
authors.lastname: Beheshti
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Qin
authors.forename: Himadri S
authors.initials: HS
authors.lastname: Mandal
authors.forename: Yi-Tao
authors.initials: YT
authors.lastname: Long
authors.forename: Hubert H
authors.initials: HH
authors.lastname: Girault
authors.forename: Heinz-Bernhard
authors.initials: HB
authors.lastname: Kraatz
mesh_terms: D016229:Amyloid beta-Peptides / Q000737:chemistry*; D003224:Congo Red / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry*; D058266:Dielectric Spectroscopy; D004563:Electrochemistry; D006046:Gold / Q000737:chemistry; D008958:Models, Molecular; D011485:Protein Binding; D017433:Protein Structure, Secondary / Q000187:drug effects; D013499:Surface Properties
chemical_list: D016229:Amyloid beta-Peptides; D003224:Congo Red; D006046:Gold; D003545:Cysteine