Molecular and Rheological Considerations of the Red Cell Membrane in View of the Internal Fluidity of the Red Cell

Abstract

The study of viscosity of blood at high heamatocrits and of packed cell systems leads to a conclusion that the interior of the red cell is fluid. The internal viscosity is suggested to be in the range from 2 to 20 centipoises. If the red cell is to exhibit fluidity, transfer of the tangential stresses (in flow) from the exterior to the interior of the red cell must not be inhibited by a rigid membrane. Consequently, the red cell membrane should be characterized by extremely low surface (interfacial) viscosity. It is suggested that a feasible model of the red cell membrane could be formed by a liquid-crystalline or micellar lattice arrangement of lipids and proteins. Such model would account naturally for the surface heterogeneity of the red cell and would supply a basis for the catalytic chemical reactions and the active transport considered to exist in the membrane.