SURFACE ELASTICITY AND VISCOSITY OF RED-CELL MEMBRANE

Force-deformation curves are measured for individual human red blood cells by applying an equal and opposite force at diametrically opposite “points” on the red cell rim. Upon release of a cell, it rapidly recovers its unstressed disklike shape in approximately 0.3 sec. This deformation and subsequent recovery process is analyzed with a constitutive equation which describes the finite deformation at constant area of a two-dimensional viscoelastic solid. From the analysis and the experimental results, values obtained for the “shear modulus of surface elasticity” and “coefficient of surface viscosity” are on the order of 4 X 10–3dyn/cm and 5 X 10-4 dyn sec/cm (P cm), respectively. © 1979, The Society of Rheology. All rights reserved.