Effects of Synthetic Amphiphilic alpha-Helical Peptides on the Electrochemical and Structural Properties of Supported Hybrid Bilayers on Gold

Journal Article · Sun Jan 01 04:00:00 EST 2006 · Langmuir

DOI:https://doi.org/10.1021/la051104w· OSTI ID:913969

Smith, M; Tong, J; Genzer, J; Fischer, D; Kilpatrick, P

Amphiphilic {alpha}-helices were formed from designed synthetic peptides comprising alanine, phenylalanine, and lysine residues. The insertion of the -helical peptides into hybrid bilayers assembled on gold was studied by a variety of methods to assess the resulting structural characteristics, such as electrical resistance and molecular orientation. Self-assembled monolayers (SAMs) of dodecanethiol (DDT); octadecanethiol (ODT); and 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE) were formed on gold substrates with and without incorporated peptide. Supported hybrid bilayers and multilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were formed on SAMs by the 'paint-freeze' method of bilayer formation. Modeling of electrochemical impedance spectroscopy data using equivalent electrochemical circuits revealed that the addition of peptide decreased dramatically the resistive element of the bilayer films while maintaining the value of the capacitive element, indicating successful incorporation of peptide into a well-formed bilayer. Near-edge X-ray absorption fine structure spectroscopy data provided evidence that the molecules in the SAMs and hybrid multilayers were ordered even in the presence of peptide. The peptide insertion into the SAM was confirmed by observing the {pi}* resonance peak correlating with phenylalanine and a peak in the nitrogen K-edge regime attributable to the peptide bond.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 913969
• Report Number(s): BNL--78537-2007-JA
• Journal Information: Langmuir, Journal Name: Langmuir Journal Issue: 4 Vol. 22; ISSN LANGD5; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALANINES
ELECTROCHEMISTRY
GOLD
LYSINE
MORPHOLOGY
PEPTIDES
PHENYLALANINE
SUBSTRATES
SYNTHETIC MATERIALS
national synchrotron light source