title: Deduction of intrinsic mechanical properties of the erythrocyte membrane from observations of tank-treading in the rheoscope.
abstract: Measurements of the dimensions and membrane rotational frequency of individual erythrocytes steadily tank-treading in a Rheoscope are used to deduce the surface shear viscosity (eta m) and the shear elastic modulus (mu m) of the membrane. Previously published algorithms (Trans-Son-Tay et al., Biophys. J. 46: 65, 1984, and 51: 915, 1987) plus an assumed area-conserving membrane velocity field (Secomb and Skalak, Q. J. Mech. Appl. Math. XXXV 2: 233, 1982) are applied to calculate eta m as a function of the second invariant of the surface strain rate and mu m as a function of the second invariant of membrane strain. The results indicate density-related increases in membrane stiffness and viscosity, shear-thinning viscous behavior, and strain-stiffening elastic behavior.
authors.affiliation: Department of Mechanical Engineering, Washington University, St. Louis, Missouri 63130.
authors.forename: S P
authors.initials: SP
authors.lastname: Sutera
authors.forename: P R
authors.initials: PR
authors.lastname: Pierre
authors.forename: G I
authors.initials: GI
authors.lastname: Zahalak
mesh_terms: D000465:Algorithms; D001809:Blood Viscosity; D004548:Elasticity; D004907:Erythrocyte Deformability / Q000502:physiology*; D004910:Erythrocyte Membrane / Q000502:physiology*; D008853:Microscopy; D008954:Models, Biological; D012212:Rheology; D013314:Stress, Mechanical