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Updated: Jun 12, 2026

Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers
Published on: July 22, 2015
Influence of ethanol on lipid/sterol membranes: phase diagram construction from AFM imaging
Juan M Vanegas1, Roland Faller, Marjorie L Longo
1Biophysics Graduate Group, College of Biological Sciences, University of California, Davis, California 95616, USA.
Abstract:
Herein we develop a sample preparation approach that enables the use of supported lipid bilayers for the quantitative study of the influence of ethanol (0-20 vol %) on the phase behavior of phospholipid (DPPC)/sterol (ergosterol, 0-20 mol %) bilayers. Three coexisting phases were observed with tapping-mode atomic force microscopy: gel (L(beta)'), liquid-ordered (L(o)), and interdigitated (L(beta)'I). High-resolution imaging permitted the construction of a refined phase diagram for DPPC/ergosterol/ethanol and the observation of L(o)-L(beta)' phase separation that has not been observed using optical techniques. Our results quantitatively show the concentration regime where ergosterol protects the membrane by reducing the membrane fraction that is interdigitated in the presence of ethanol.
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