Effect of electric field on structure and dynamics of bilayers formed from anionic phospholipids

Elena Madrid, Sarah L. Horswell

Research output: Contribution to journalArticle

19 Citations (Scopus)
143 Downloads (Pure)

Abstract

The effect of molecular structure on ensemble structure and dynamics of phospholipid bilayers has been investigated. Bilayers of dimyristoyl phosphatidylserine (DMPS) supported on Au(111) surfaces were prepared by Langmuir-Blodgett and Langmuir-Schaeffer deposition and studied with a combination of electrochemical measurements and in situ Polarisation Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS). DMPS bilayers have relatively large capacitance when compared with those formed from similar molecules and this is attributed to a high solvent content within the bilayer, resulting from the need for solvation of the negatively charged lipid headgroups. Infrared spectra show that the ensemble of molecules is in a gel state, with extended and ordered hydrocarbon chains, similarly to bilayers of dimyristoyl phosphatidylethanolamine (DMPE) molecules, which are of similar shape. The infrared spectra also show that, in contrast to DMPE, the headgroups of DMPS are very strongly hydrated and have higher mobility. This higher mobility allows the re-orientation of the molecules under the influence of an applied electric field: re-orientation both of headgroups and hydrocarbon tail groups is observed. Thus the shape and charge of the molecules in an ensemble have a strong influence on both their structure and dynamics in the presence of an externally applied electric field.

Original languageEnglish
Pages (from-to)850-860
Number of pages11
JournalElectrochimica Acta
Volume146
Early online date21 Jan 2014
DOIs
Publication statusPublished - 10 Nov 2014

Keywords

  • Adsorption, Phospholipid
  • Biomimetic membrane
  • Infrared spectroscopy
  • Spectroelectrochemistry

ASJC Scopus subject areas

  • Electrochemistry
  • Chemical Engineering(all)

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