Issue
EPL
Volume 84, Number 4, November 2008
Article Number 48003
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/84/48003
Published online 12 November 2008
EPL, 84 (2008) 48003
DOI: 10.1209/0295-5075/84/48003

Adhesion promotes phase separation in mixed-lipid membranes

V. D. Gordon1, M. Deserno2, 3, C. M. J. Andrew1, S. U. Egelhaaf1, 4 and W. C. K. Poon1

1   SUPA, School of Physics, and COSMIC, The University of Edinburgh, James Clerk Maxwell Building, Kings Buildings - Mayfield Road, Edinburgh, EH9 3JZ, Scotland, UK, EU
2   Max-Planck-Institut für Polymerforschung - Ackermannweg 10, 55128 Mainz, Germany, EU
3   Department of Physics, Carnegie Mellon University - Pittsburgh, PA 15213-3890, USA
4   Condensed Matter Physics Laboratory, Heinrich-Heine-University - D-40225 Düsseldorf, Germany, EU

w.poon@ed.ac.uk

received 27 June 2008; accepted in final form 7 October 2008; published November 2008
published online 12 November 2008

Abstract
We investigate the interplay of domain formation and adhesion in mixed-lipid membranes. Giant unilamellar vesicles consisting of two- and three-component lipid mixtures are studied using confocal fluorescence microscopy. Upon driving the system towards the demixing transition, phase separation is invariably found to occur first in regions where membranes adhere to one another, despite identical lipid headgroups and negligible curvature effects. We propose a simple generic mechanism based on the suppression of thermal shape fluctuations to explain these observations. Our findings suggest novel possibilities by which biomembranes can create and utilize lateral lipid heterogeneities.

PACS
87.16.D- - Membranes, bilayers, and vesicles.
64.75.St - Phase separation and segregation in thin films.
87.17.Rt - Cell adhesion and cell mechanics.

© EPLA 2008