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Biophys J. 1998 September; 75(3): 1584–1597.
PMCID: PMC1299832
Simulations of the erythrocyte cytoskeleton at large deformation. II. Micropipette aspiration.
D E Discher, D H Boal, and S K Boey
University of Pennsylvania, Philadelphia 19104-6315, USA. discher@eniac.seas.upenn.edu
Abstract
Coarse-grained molecular models of the erythrocyte membrane's spectrin cytoskeleton are presented in Monte Carlo simulations of whole cells in micropipette aspiration. The nonlinear chain elasticity and sterics revealed in more microscopic cytoskeleton models (developed in a companion paper; Boey et al., 1998. Biophys. J. 75:1573-1583) are faithfully represented here by two- and three-body effective potentials. The number of degrees of freedom of the system are thereby reduced to a range that is computationally tractable. Three effective models for the triangulated cytoskeleton are developed: two models in which the cytoskeleton is stress-free and does or does not have internal attractive interactions, and a third model in which the cytoskeleton is prestressed in situ. These are employed in direct, finite-temperature simulations of erythrocyte deformation in a micropipette. All three models show reasonable agreement with aspiration measurements made on flaccid human erythrocytes, but the prestressed model alone yields optimal agreement with fluorescence imaging experiments. Ensemble-averaging of nonaxisymmetrical, deformed structures exhibiting anisotropic strain are thus shown to provide an answer to the basic question of how a triangulated mesh such as that of the red cell cytoskeleton deforms in experiment.
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Selected References
These references are in PubMed. This may not be the complete list of references from this article.
  • Boal, DH. Computer simulation of a model network for the erythrocyte cytoskeleton. Biophys J. 1994 Aug;67(2):521–529. [PubMed]
  • Boal, DH; Rao, M. Topology changes in fluid membranes. Phys Rev A. 1992 Sep 15;46(6):3037–3045. [PubMed]
  • Boal, DH; Seifert, U; Shillcock, JC. Negative Poisson ratio in two-dimensional networks under tension. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 1993 Dec;48(6):4274–4283. [PubMed]
  • Boey, SK; Boal, DH; Discher, DE. Simulations of the erythrocyte cytoskeleton at large deformation. I. Microscopic models. Biophys J. 1998 Sep;75(3):1573–1583. [PubMed]
  • Byers, TJ; Branton, D. Visualization of the protein associations in the erythrocyte membrane skeleton. Proc Natl Acad Sci U S A. 1985 Sep;82(18):6153–6157. [PubMed]
  • Discher, DE; Mohandas, N. Kinematics of red cell aspiration by fluorescence-imaged microdeformation. Biophys J. 1996 Oct;71(4):1680–1694. [PubMed]
  • Discher, DE; Mohandas, N; Evans, EA. Molecular maps of red cell deformation: hidden elasticity and in situ connectivity. Science. 1994 Nov 11;266(5187):1032–1035. [PubMed]
  • Evans, E; Ritchie, K. Dynamic strength of molecular adhesion bonds. Biophys J. 1997 Apr;72(4):1541–1555. [PubMed]
  • Hansen, JC; Skalak, R; Chien, S; Hoger, A. An elastic network model based on the structure of the red blood cell membrane skeleton. Biophys J. 1996 Jan;70(1):146–166. [PubMed]
  • Liu, SC; Derick, LH; Palek, J. Visualization of the hexagonal lattice in the erythrocyte membrane skeleton. J Cell Biol. 1987 Mar;104(3):527–536. [PubMed]
  • MacKintosh, FC; Käs, J; Janmey, PA. Elasticity of semiflexible biopolymer networks. Phys Rev Lett. 1995 Dec 11;75(24):4425–4428. [PubMed]
  • Mohandas, N; Evans, E. Mechanical properties of the red cell membrane in relation to molecular structure and genetic defects. Annu Rev Biophys Biomol Struct. 1994;23:787–818. [PubMed]
  • Mohandas, N; Groner, W. Cell membrane and volume changes during red cell development and aging. Ann N Y Acad Sci. 1989;554:217–224. [PubMed]
  • Peters, LL; Shivdasani, RA; Liu, SC; Hanspal, M; John, KM; Gonzalez, JM; Brugnara, C; Gwynn, B; Mohandas, N; Alper, SL; Orkin, SH; Lux, SE. Anion exchanger 1 (band 3) is required to prevent erythrocyte membrane surface loss but not to form the membrane skeleton. Cell. 1996 Sep 20;86(6):917–927. [PubMed]
  • RAND, RP; BURTON, AC. MECHANICAL PROPERTIES OF THE RED CELL MEMBRANE. I. MEMBRANE STIFFNESS AND INTRACELLULAR PRESSURE. Biophys J. 1964 Mar;4:115–135. [PubMed]
  • Rief, M; Gautel, M; Oesterhelt, F; Fernandez, JM; Gaub, HE. Reversible unfolding of individual titin immunoglobulin domains by AFM. Science. 1997 May 16;276(5315):1109–1112. [PubMed]
  • Svoboda, K; Schmidt, CF; Branton, D; Block, SM. Conformation and elasticity of the isolated red blood cell membrane skeleton. Biophys J. 1992 Sep;63(3):784–793. [PubMed]
  • Waugh, R; Evans, EA. Thermoelasticity of red blood cell membrane. Biophys J. 1979 Apr;26(1):115–131. [PubMed]