Author/Editor		Kuzman, D; Svetina, S; Waugh, RE; Žekš, B
Title		Elastic properties of the red blood cell membrane that determine echinocyte deformability
Type		članek
Source		Eur Biophys J
Vol. and No.		Letnik 33
Publication year		2004
Volume		str. 1-15
Language		eng
Abstract		The natural biconcave shape of red blood cells (RBC) may be altered by injury or environmental conditions into a spiculated form (echinocyte). An analysis is presented of the effect of such a transformation on the resistance of RBC to entry into capillary sized cylindrical tubes. The analysis accounts for the elasticity of the membrane skeleton in dilation and shear, and the local and nonlocal resistance of the bilayer to bending, the latter corresponding to different area strains in the two leaflets of the bilayer. The shape transformation is assumed to be driven by the equilibrium area difference (deltaA0, the difference between the equilibrium areas of the bilayer leaflets), which also affects the energy of deformation. The cell shape is approximated by a parametric model. Shape parameters, skeleton shear deformation, and the skeleton density of deformed membrane relative to the skeleton density of undeformed membrane are obtained by minimization of the corresponding thermodynamic potential. Experimentally, deltaA0 is modified and the corresponding discocyte-chinocyte shape transition obtained by high-pressure aspiration into a narrow pipette, and the deformability of the resulting echinocyte is examined by whole cell aspiration into a larger pipette. We conclude that the deformability of the echinocyte can be accounted for by the mechanical behavior of the normal RBC membrane, where the equilibrium area difference deltaA0 is modified.
Descriptors		LIPID BILAYERS ELASTICITY ERYTHROCYTE MEMBRANE ERYTHROCYTE DEFORMABILITY CAPILLARITY THERMODYNAMICS MODELS, THEORETICAL