Periodic lipidic membrane tubes

¹  Departament d'Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona - Diagonal 647, E-08028 Barcelona, Spain
²  Laboratoire de Physique Statistique, École Normale Supérieure - 24 rue Lhomond, F-75231 Paris Cedex 05, France
³  Biomedical Engineering Department, Boston University - 44 Cummington Street, Boston, MA 02215, USA

Received: 25 July 2006
Accepted: 11 December 2006

Abstract

We investigate the formation of two-phase lipidic tubes of membrane in the framework of the Canham-Helfrich model. The two phases have different elastic moduli (bending and Gaussian rigidity), different tensions and a line tension prevents the mixing. For a set of parameters close to experimental values, periodic patterns with arbitrary wavelength can be found numerically. A wavelength selection is detected via the existence of an energy minimum. When the chemical composition induces an important enough size disequilibrium between both phases, a segregation into two half infinite tubes is preferred to a periodic structure.