Electroporation Threshold of POPC Lipid Bilayers with Incorporated Polyoxyethylene Glycol (C12E8)

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• 作者：Andra啪 Polak ; Alja啪 Velikonja ; Peter Kramar ; Mounir Tarek ; Damijan Miklav膷i膷
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：January 8, 2015
• 年：2015
• 卷：119
• 期：1
• 页码：192-200
• 全文大小：409K
• ISSN：1520-5207

文摘

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.