A New Method for Measuring Edge Tensions and Stability of Lipid Bilayers: Effect of Membrane Composition

We report a novel and facile method for measuring edge tensions of lipid membranes. The approach is based on electroporation of giant unilamellar vesicles and analysis of the pore closure dynamics. We applied this method to evaluate the edge tension in membranes with four different compositions: egg...

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Bibliographic Details
Published in:Biophysical journal 2010-11, Vol.99 (10), p.3264-3273
Main Authors: Portet, Thomas, Dimova, Rumiana
Format: Article
Language:English
Subjects:
Animals
Cells
Chickens
Cholesterol
Cholesterol - chemistry
Dynamic tests
Egg Yolk - chemistry
Electricity
Electroporation
Electroporation - methods
Hydrogen bonding
Imaging, Three-Dimensional
Life Sciences
Lipid Bilayers - chemistry
Lipids
Membrane
Membranes
Molecules
Phosphatidylcholines - chemistry
Physics
Porosity
Stability
Surface Tension
Time Factors
Vesicles
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Summary:We report a novel and facile method for measuring edge tensions of lipid membranes. The approach is based on electroporation of giant unilamellar vesicles and analysis of the pore closure dynamics. We applied this method to evaluate the edge tension in membranes with four different compositions: egg phosphatidylcholine (eggPC), dioleoylphosphatidylcholine (DOPC), and mixtures of DOPC with cholesterol and dioleoylphosphatidylethanolamine. Our data confirm previous results for eggPC and DOPC. The addition of 17 mol % cholesterol to the DOPC membrane causes an increase in the membrane edge tension. On the contrary, when the same fraction of dioleoylphosphatidylethanolamine is added to the membrane, a decrease in the edge tension is observed, which is an unexpected result considering the inverted-cone shape geometry of the molecule. It is presumed that interlipid hydrogen bonding is the origin of this behavior. Furthermore, cholesterol was found to lower the lysis tension of DOPC bilayers. This behavior differs from that observed on bilayers made of stearoyloleoylphosphatidylcholine, suggesting that cholesterol influences the membrane mechanical stability in a lipid-specific manner.
ISSN:0006-3495
1542-0086
DOI:10.1016/j.bpj.2010.09.032