title: Morphology transition in lipid vesicles due to in-plane order and topological defects.
abstract: Complex morphologies in lipid membranes typically arise due to chemical heterogeneity, but in the tilted gel phase, complex shapes can form spontaneously even in a membrane containing only a single lipid component. We explore this phenomenon via experiments and coarse-grained simulations on giant unilamellar vesicles of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine. When cooled from the untilted L(α) liquid-crystalline phase into the   tilted gel phase, vesicles deform from smooth spheres to disordered, highly crumpled shapes. We propose that this shape evolution is driven by nucleation of complex membrane microstructure with topological defects in the tilt orientation that induce nonuniform membrane curvature. Coarse-grained simulations demonstrate this mechanism and show that kinetic competition between curvature change and defect motion can trap vesicles in deeply metastable, defect-rich structures.
authors: Physics Department, University of California, Merced, CA 95343, USA. lhirst@ucmerced.edu
authors: Linda S
authors: LS
authors: Hirst
authors: Adam
authors: A
authors: Ossowski
authors: Matthew
authors: M
authors: Fraser
authors: Jun
authors: J
authors: Geng
authors: Jonathan V
authors: JV
authors: Selinger
authors: Robin L B
authors: RL
authors: Selinger
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D008859:Microscopy, Polarization; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D044367:Phase Transition; D012399:Rotation; D053835:Unilamellar Liposomes / Q000737:chemistry*; D014783:Viscosity
chemical_list: D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D053835:Unilamellar Liposomes; D015060:1,2-Dipalmitoylphosphatidylcholine
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