title: Coupling of bending and stretching deformations in vesicle membranes.
abstract: Biomimetic membranes are fluid and can undergo two different elastic deformations, bending and stretching. The bending of a membrane is primarily governed by two elastic parameters: its spontaneous (or preferred) curvature m and its bending rigidity κ. These two parameters define an intrinsic tension scale, the spontaneous tension 2 κm². Membrane stretching and compression, on the other hand, are determined by the mechanical tension acting within the membrane. For vesicle membranes, the two elastic deformations are coupled via the enclosed vesicle volume even in the absence of mechanical forces as shown here by minimizing the combined bending and stretching energy with respect to membrane area for fixed vesicle volume. As a consequence, the mechanical tension within a vesicle membrane depends on the spontaneous curvature and on the bending rigidity. This interdependence, which is difficult to grasp intuitively, is then illustrated for a variety of simple vesicle shapes. Depending on the vesicle morphology, the magnitude of the mechanical tension can be comparable to or can be much smaller than the spontaneous tension.
authors.affiliation: Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany. Electronic address: lipowsky@mpikg.mpg.de.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lipowsky
mesh_terms: D000268:Adhesiveness; D000465:Algorithms; D032701:Biomimetics / Q000379:methods* / Q000639:trends; D055598:Chemical Phenomena; D004548:Elasticity; D054459:Elasticity Imaging Techniques; D008567:Membranes, Artificial; D008956:Models, Chemical; D013499:Surface Properties; D053835:Unilamellar Liposomes / Q000737:chemistry
chemical_list: D008567:Membranes, Artificial; D053835:Unilamellar Liposomes
keywords: Compressible membranes; Curvature elasticity; Mechanical tension; Membranes and vesicles; Spontaneous curvature