Vesicle Shapes and Shape Transformations: A Systematic Study
The lipid bilayer vesicle is the simplest possible model of biological membranes. Nevertheless, it exhibits already a number of typical properties of cell membranes. The most fascinating examples are the shape transitions and shape instabilities. It has been recognized long ago that shape transitions may be induced by changing the osmotic conditions or the temperature1. Apart from spherical and ellipsoidal shapes more exotic shapes such as e. g. discocytes, stomatocytes1, echinocytes2 or a necklace of small vesicles3 has recently been observed. Up to now, our understanding of these shape transformations has been rather limited. Indeed, all previous experiments have been performed with relatively complex systems containing, e. g. charged and unsaturated lipids, mixtures of different lipids or additional solutes such as sugar in the aqueous phase. It was generally believed that these different ingredients play an essential role in determining the vesicle shape. Therefore, no attempt has been reported so far to relate these experimentally observed shapes in a systematic way to theoretical calculations.
KeywordsShape Transition Area Difference Spontaneous Curvature Cover Slide Prolate Ellipsoid
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