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Colloids Surf B Biointerfaces. 2014 Apr 1;116:295-302. doi: 10.1016/j.colsurfb.2013.12.049. Epub 2014 Jan 19.

Structural and nanomechanical effects of cholesterol in binary and ternary spin-coated single lipid bilayers in dry conditions.

Author information

  • 1Nanobioelec group, Institut de Bioenginyeria de Catalunya (IBEC), Baldiri i Reixac 15-21, 08028, Barcelona, Spain; Departament d'Electrònica, Universitat de Barcelona, C/Martí i Franquès 1, 08028 Barcelona, Spain. Electronic address: adols@ibecbarcelona.eu.
  • 2Nanobioelec group, Institut de Bioenginyeria de Catalunya (IBEC), Baldiri i Reixac 15-21, 08028, Barcelona, Spain; Departament d'Electrònica, Universitat de Barcelona, C/Martí i Franquès 1, 08028 Barcelona, Spain.
  • 3Nanobioelec group, Institut de Bioenginyeria de Catalunya (IBEC), Baldiri i Reixac 15-21, 08028, Barcelona, Spain; Departament d'Electrònica, Universitat de Barcelona, C/Martí i Franquès 1, 08028 Barcelona, Spain. Electronic address: ggomila@ibecbarcelona.eu.

Abstract

We investigate the effects of Cholesterol (Chol) in the structural and nanomechanical properties of binary and ternary spin-coated single lipid bilayers made of Dioleoylphosphatidylcholine (DOPC) and Sphingomyelin (SM) in dry conditions. We show that for the DOPC/Chol bilayers, Chol induces an initial increase of the bilayer thickness, followed by decrease for concentrations above 30% Chol. The mechanical properties, instead, appear practically insensitive to the Chol content. For the SM/Chol bilayers we have observed both the thinning of the bilayer and the decrease of the force necessary to break it for Chol content above 40 mol%. In both binary mixtures phase separation is not observed. For ternary single bilayers of DOPC/SM/Chol, Chol induces phase segregation and the formation of domains resembling lipid rafts. The domains show a thickness and mechanical response clearly distinct from the surrounding phase and dependent on the relative Chol content. Based on the results obtained for the binary mixtures, DOPC- and SM-enriched domains can be identified. We highlight that many of the effects of Chol reported here for the dry multicomponent single lipid bilayers resemble closely those observed in hydrated bilayers, thus offering an additional insight into their properties.

Copyright © 2014 Elsevier B.V. All rights reserved.

KEYWORDS:

AFM; Air-stable lipid layer; Force spectroscopy; Lipid raft; Spin-coating

PMID:
24508809
[PubMed - in process]
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