Europhys. Lett.
Volume 70, Number 5, June 2005
Page(s) 690 - 696
Section Interdisciplinary physics and related areas of science and technology
Published online 04 May 2005
Europhys. Lett., 70 (5), pp. 690-696 (2005)
DOI: 10.1209/epl/i2004-10527-4

Nonaxisymmetric phospholipid vesicles: Rackets, boomerangs, and starfish

P. Ziherl1, 2 and S. Svetina2, 3

1  Department of Physics, University of Ljubljana - Ljubljana, Slovenia
2  J. Stefan Institute - Ljubljana, Slovenia
3  Institute of Biophysics, Faculty of Medicine, University of Ljubljana Ljubljana, Slovenia

received 4 August 2004; accepted in final form 15 April 2005
published online 4 May 2005

Within the area difference elasticity model, we numerically minimize the bending energy of phospholipid vesicles to study the nonaxisymmetric shapes at the oblate-prolate transition. We analyze the onset of a coherent structural hierarchy of hybrid shapes such as rackets, boomerangs, and starfish, which all consist of a flattened body and one or more elongated arms. The phase diagram of these shapes is characterized by a critical point terminating the line of discontinuous transitions between rackets and boomerangs/starfish. The critical point is located very close to the discocyte with the volume of a human erythrocyte, implying that in this part of the parameter space minute variations of volume and area difference can induce large changes of shape.

87.16.-b - Subcellular structure and processes.
87.16.Ac - Theory and modeling; computer simulation.
87.16.Dg - Membranes, bilayers, and vesicles.

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