A kinetic measurement of the red cell deformability is developed, modifying the micropipette aspiration technique of BRAASCH (1971). The sedimented human red cells on a slide-glass are individually aspirated into a micropipette by negative pressure (ΔP), and the decreasing “velocity (v)” of the applied electric current, due to the aspirating cell, is taken as a measure of the “easiness” of the cell to enter into the small orifice of the micropipette (inner diameter, 2R≈3μm). An empirical relation, v∝(πR2)·(ΔP)·(“deformability”), is obtained.
In order to test the validity of the method, some factors influencing the deformability are studied: i. e., the “velocity” decreases as lowering temperature; the “velocity” of the glutaraldehyde-pretreated cells and of both in vivo and in vitro aged cells decreases. Therefore, the parameter, “velocity (v), ” reflects the deformability well. In addition, if a few assumptions could be allowed, v would be related to the Young's modulus of the membrane.
