Measurement of Elasticity of Erythrocytes Using Atomic Force Microscope

Abstract

Deformability of erythrocyte is a crucial factor to maintain smooth blood flow in the microcirculation supplying oxygen and nutriments to organic tissues. Decrease in the deformability depends on the elasticity of erythrocyte, especially on the cell membrane structure that leads to high shear stress on the blood vessel wall and significant increase in the flow resistance. In this study, microscopic elastic property of the erythrocyte under diabeteic and another physical conditions were measured by using atomic force microscope (AFM) in the contact mode function. The spring constant k and the Young's modulus E of erythrocytes were derived from the so-called force curve applying the Hooke's law and the Hertz model. In case of the compressing force of AFM at 1.5nN, k and E of healthy erythrocytes were 7-9mN/m and 0.1-0.15MPa while diabetic samples showed significantly higher elasticity than those of healthy samples. This implies the diabetic erythrocytes change to be stiff as the result of glycosylation of cell membrane that may induce microangiopathy.