Electroporation threshold of POPC lipid bilayers with incorporated polyoxyethylene glycol (C12E8)

J Phys Chem B. 2015 Jan 8;119(1):192-200. doi: 10.1021/jp509789m. Epub 2014 Dec 26.

Abstract

Electroporation relates to a phenomenon in which cell membranes are permeabilized after being exposed to high electric fields. On the molecular level, the mechanism is not yet fully elucidated, although a considerable body of experiments and molecular dynamic (MD) simulations were performed on model membranes. Here we present the results of a combined theoretical and experimental investigation of electroporation of palmitoy-oleoyl-phosphatidylcholine (POPC) bilayers with incorporated polyoxyethylene glycol (C12E8) surfactants. The experimental results show a slight increase of the capacitance and a 22% decrease of the voltage breakdown upon addition of C12E8 to pure POPC bilayers. These results were qualitatively confirmed by the MD simulations. They later revealed that the polyoxyethylene glycol molecules play a major role in the formation of hydrophilic pores in the bilayers above the electroporation threshold. The headgroup moieties of the latter are indeed embedded in the interior of the bilayer, which favors formation of water wires that protrude into its hydrophobic core. When the water wires extend across the whole bilayer, they form channels stabilized by the C12E8 head groups. These hydrophilic channels can transport ions across the membrane without the need of major lipid head-group rearrangements.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electroporation*
  • Lipid Bilayers / chemistry*
  • Molecular Dynamics Simulation
  • Molecular Structure
  • Phosphatidylcholines / chemistry*
  • Polyethylene Glycols / chemistry*

Substances

  • Lipid Bilayers
  • Phosphatidylcholines
  • Polyethylene Glycols
  • 1-palmitoyl-2-oleoylphosphatidylcholine