PM-IRRAS studies of DMPC bilayers supported on Au(111) electrodes modified with hydrophilic monolayers of thioglucose
| Autor: | J. Jay Leitch, Dorota Matyszewska, Jacek Lipkowski, ZhangFei Su, Fatemah Abbasi, Renata Bilewicz |
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| Předmět: |
polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS)
Absorption spectroscopy Infrared Lipid Bilayers Nanotechnology 02 engineering and technology 010402 general chemistry 01 natural sciences Monolayer Electrochemistry General Materials Science model lipid membrane Lipid bilayer Electrodes Spectroscopy Chemistry Spectrum Analysis technology industry and agriculture Biological membrane Surfaces and Interfaces 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Crystallography Glucose Reflection (mathematics) Deuterium Electrode lipids (amino acids peptides and proteins) Gold Dimyristoylphosphatidylcholine 0210 nano-technology Hydrophobic and Hydrophilic Interactions |
| Zdroj: | Langmuir : the ACS journal of surfaces and colloids |
| DOI: | 10.1021/acs.langmuir.5b04052 |
| Popis: | This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.langmuir.5b04052 A phospholipid bilayer composed of 1,2-dimyristoyl-d54-sn-glycero-3-phosphocholine (d54-DMPC) was deposited onto the Au(111) electrode modified with a self-assembled monolayer of 1-thio-β-d-glucose (β-Tg) via the Langmuir–Blodgett and Langmuir–Schaefer (LB-LS) techniques. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) measurements were used to characterize structural and orientational changes in this model biological membrane on a hydrophilic surface modified gold electrode. The results of the spectroscopic measurements showed that the tilt angle of acyl chains obtained for deuterated DMPC bilayers supported on the β-Tg-modified gold is significantly lower than that reported previously for DMPC bilayers deposited directly on Au(111) electrodes. Moreover, tilt angles of ∼18° were obtained for d54-DMPC bilayers on β-Tg self-assembled monolayers (SAMs) at positive potentials, which are similar to the values calculated for h-DMPC deposited on bare gold in the desorbed state and to those observed for a stack of hydrated DMPC bilayers. This data confirms that the β-thioglucose SAM promotes the formation of a water cushion that separates the phospholipid bilayer from the metal surface. As a result, the DMPC polar heads are not in direct contact with the electrode and can adopt a zigzag configuration, which strengthens the chain–chain interactions and allows for an overall decrease in the tilt of the acyl chains. These novel supported model membranes may be especially useful in studies pertaining to the incorporation of peptides and proteins into phospholipid bilayers. Sinergia project no. CRSII2_154451/1 financed by the Swiss National Science Foundation and Discovery grant from the Natural Sciences and Engineering Research Council of Canada |
| Databáze: | OpenAIRE |
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