Eur. Phys. J. E 1, 237-248
Inclusions induced phase separation in mixed lipid film
Department of Materials and Interfaces, Weizmann Institute of
Science,
Rehovot 76100, Israel
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Received 8 April 1999 and Received in final form 4 October 1999
Abstract
The effect of rigid inclusions on the phase behavior of a film containing a
mixture of lipid molecules is investigated. In the proposed model, the inclusion-induced
deformation of the film, and the resulting energy cost are strongly dependent upon the
spontaneous curvature of the mixed film. The spontaneous curvature is in turn strongly
influenced by the composition of film. This coupling between the film composition and the
energy per inclusion leads to a lateral modulation of the composition, which follows the
local curvature of the membrane. In particular, it is shown that inclusions may induce
a global phase separation in a film which would otherwise be homogeneously mixed. The
mixed film is then composed of patches of different average composition, separated by the
inclusions. This process may be of relevance to explain some aspects of lipid-protein
association in biological membranes.
PACS
87.16.Dg Membranes, bilayers, and vesicles
-
64.75.+g Solubility, segregation, and mixing;
phase separation
-
82.65.Dp Thermodynamics of surfaces and
interfaces
Copyright EDP Sciences, Società Italiana di Fisica, Springer-Verlag
