Red Cell Biconcavity and Deformability A macromodel based on flow chamber observations

Abstract

The biconcave shape of the red cell has fascinated investigators for more than two centuries. Several theories have been proposed and macro-models built in an attempt to explain this phenomenon. Biconcavity is not the only curious physical characteristic of the red cell membrane, for it possesses other unusual physical features such as the ability to transform from a sphere into a disk, uniform physical properties over both dimple and annulus, constant surface area, and high ultimate tensile strength— all coupled with great deformability. These properties, some of which are paradoxical, have not been adequately explained by the theories and models proposed to date. Recent observations in a flow chamber have delineated additional characteristics of the red cell membrane which a model should satisfy. This communication describes both the flow chamber observations and a new macromodel of the red cell membrane.