Fluctuation mediated interactions due to rigidity mismatch and their effect on miscibility of lipid mixtures in multicomponent membranes

David S. Dean (1) , V. Adrian Parsegian (2) , Rudolf Podgornik (2, 3, 4)

1 LOMA - Laboratoire Ondes et Matière d'Aquitaine
2 Department of Physics
3 Department of Theoretical Physics
4 Department of Physics, Faculty of Mathematics and Physics

We consider how membrane fluctuations can modify the miscibility of lipid mixtures, that is to say how the phase diagram of a boundary-constrained membrane is modified when the membrane is allowed to fluctuate freely in the case of zero surface tension. In order for fluctuations to have an effect, the different lipid types must have differing Gaussian rigidities. We show, somewhat paradoxically, that fluctuation-induced interactions can be treated approximately in a mean-field type theory. Our calculations predict that, depending on the difference in bending and Gaussian rigidity of the lipids, membrane fluctuations can either favor or disfavor mixing.

Mots clés: Fluctuation forces; Lipids; Mixing-demixing transition

Domaines: Matière Molle [cond-mat.soft]

David S. Dean, V. Adrian Parsegian, Rudolf Podgornik. Fluctuation mediated interactions due to rigidity mismatch and their effect on miscibility of lipid mixtures in multicomponent membranes. Journal of Physics: Condensed Matter, 2015, 27 (21), pp.214004 (1-10). ⟨10.1088/0953-8984/27/21/214004⟩. ⟨hal-01158092⟩