The area expansion modulus of RBC membranes is mainly dominated by the elasticity of the bilayer. Where T t, A 0, and A correpond to the isotopic tensile force, the original surface area, and the increase in surface area, respectively ( Hochmuth and Waugh,1987). Compared to a spherical shape, RBCs with biconcave shape have less volume for a given surface area, which can decrease bending energy associated with the membrane ( Canham,1970). The biconcave shape of normal RBCs has advantages in having deformability. RBCs gradually lose their deformability with age and eventually rupture in spleen. Throughout their life span of 100-120 days, human RBCs circulate the body delivering oxygen from the lungs to tissues. In mammals, RBCs develope from nucleated progenitor cells in bone mellow but RBCs discard their nucleus as they mature, whereas RBCs of other vertebrates have nuclei. Depending on species, RBC shape and size vary.

A typical human RBC has a thickness of 2-3 μm, diameter of 6-8 μm, cell volume of 90 fl, and surface area of approximately 136 μm 2 ( Kenneth,2010).

Mature human RBCs have a biconcave disc shape and they do not contain nucleus or subcellular structures but mainly consist of Hb solution in the cytoplasm ( Fig. For each technique, we seek to provide insights how these deformability measurement techniques can improve the study of RBC pathophysiology. This chapter reviews a variety of tools for measuring RBC deformability. For the past years, various experimental techniques have been developed to measure RBC deformability and recent technical advances revolutionize the way we study RBCs and their roles in hematology. Hence, measuring the deformability of RBCs holds the key to understanding RBC related diseases. RBC deformability can be significantly altered by various pathophysiological conditions, and the alterations in RBC deformability in turn influence pathophysiology, since RBC deformability is an important determinant of blood viscosity and thus blood circulation. RBCs must withstand large deformations during repeated passages through the microvasculature and the fenestrated walls of the splenic sinusoids ( Waugh and Evans,1979). The deformability of RBCs plays crucially important roles in the main function of RBCs - oxygen transport through blood circulation. Upon external forces, RBCs undergo large mechanical deformation without rupture, and they restore to original shapes when released.

Human red blood cells (RBCs) or erythrocytes have remarkable deformability.

Test viscosity of hemoglobin in rbc