title: Flat and sigmoidally curved contact zones in vesicle-vesicle adhesion.
abstract: Using the membrane-bending elasticity theory and a simple effective model of adhesion, we study the morphology of lipid vesicle doublets. In the weak adhesion regime, we find flat-contact axisymmetric doublets, whereas at large adhesion strengths, the vesicle aggregates are nonaxisymmetric and characterized by a sigmoidally curved, S-shaped contact zone with a single invagination and a complementary evagination on each vesicle. The sigmoid-contact doublets agree very well with the experimentally observed shapes of erythrocyte aggregates. Our results show that in identical vesicles with large to moderate surface-to-volume ratio, the sigmoid-contact shape is the only bound morphology. We also discuss the role of sigmoid contacts in the formation of multicellular aggregates such as erythrocyte rouleaux.
authors.affiliation: Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia. primoz.ziherl@ijs.si
authors.forename: P
authors.initials: P
authors.lastname: Ziherl
authors.forename: S
authors.initials: S
authors.lastname: Svetina
mesh_terms: D000268:Adhesiveness; D002448:Cell Adhesion; D002462:Cell Membrane; D003198:Computer Simulation; D004548:Elasticity; D004912:Erythrocytes / Q000166:cytology*; D046529:Microscopy, Electron, Transmission; D008954:Models, Biological