The measurement of shear modulus and membrane surface viscosity of RBC membrane with Ektacytometry: A new technique

A new technique is proposed to estimate the shear modulus (p) and membrane surface viscosity (eta(m)) of red blood cell (RBC). Theoretical formulae for finding these two parameters are first derived based on the force balance on a RBC in a flow field of low viscosity. Different types of Ektacytometry are then used to measure relevant quantities. The obtained values (mu = 6.1 x 10(-6) N/m, eta(m) = 8.8 X 10(-7) N s/m for normal RBC) are consistent with those previously found by micropipette technique and in AC electric field. The present technique is, however, much easier to operate and more advantageous in reflecting the average properties of a large quantity of RBCs, and it is much cheaper to be applied in clinical practice than any other method of measuring the two parameters. The sensitivity of the technique is demonstrated by