Echinocyte shapes: bending, stretching, and shear determine spicule shape and spacing.
We study the shapes of human red blood cells using continuum mechanics. In particular, we model the crenated, echinocytic shapes and show how they may arise from a competition between the bending energy of the plasma membrane and the stretching/shear elastic energies of the membrane skeleton. In contrast to earlier work, we calculate spicule shapes exactly by solving the equations of continuum mechanics subject to appropriate boundary conditions. A simple scaling analysis of this competition reveals an elastic length Lambda(el), which sets the length scale for the spicules and is, thus, related to the number of spicules experimentally observed on the fully developed echinocyte.
Mukhopadhyay
Ranjan
R
Department of Physics, Simon Fraser University Burnaby, British Columbia, V5A 1S6 Canada. ranjan@research.nj.nec.com
Lim H  W
Gerald
G
Wortis
Michael
M
D000818:Animals; D001667:Binding, Competitive; D055592:Biophysical Phenomena; D001703:Biophysics; D002462:Cell Membrane / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D004912:Erythrocytes / Q000737:chemistry* / Q000166:cytology*; D007700:Kinetics; D015233:Models, Statistical; D013816:Thermodynamics