LINEAR RESPONSE OF THE HUMAN ERYTHROCYTE TO MECHANICAL-STRESS

The human erythrocyte readily changes its shape in response to mechanical stress. Geometrical methods are used to analyze this effect in three experiments: thermal shape fluctuation (flicker), electro-deformation, and tank treading, which is the circulation of the membrane around the interior fluid in a shear flow. Comparison with existing data indicates that both flicker and tank treading represent the motion of a fluid membrane. At the same time it is a solid membrane (i.e., possessing a shear modulus) that resists large-scale shape change. This combination of fluid and solid membrane properties is in some ways paradoxical.