Can we use PBS as an alternative to Dextran in Ektacytometric measurement?

Abstract

In order to find a new suspending medium for Ektacytometric measurement, comparisons of measured rheological properties of erythrocyte suspension in different buffers were carried out. Two kinds of buffer were used, e.g. PBS and PVP. And four types of erythrocyte were measured by using both suspending media, namely: normal rabbit's erythrocytes (RBC), rabbit's RBC hardened by formalin with different concentrations, rabbit's RBC treated by trypsin and human erythrocyte sampled from patients. Microscopic and scanning electron microscopic photographs of erythrocytes rigidizied at constant shear rate were observed. Results showed that (1) for everyone of the these four kinds of erythrocytes, measured deformation index (D1)—shear rate ( $\dot{\gamma}$ ) curves in PBS are similar qualitatively to those measured in PVP. (2) Microscopic and scanning electron microscopic photographs showed that erythrocytes indeed deformed when the shear rate of flow field for PBS was as low as $\dot{\gamma}=20s^{-1}$ . It indicated that PBS could be used as suspending medium. On the contrary when we used PVP ( $\dot{\eta}=2$ mPas Fig. 1 [1]) as suspending medium at $\dot{\gamma}=800s^{-1}$ , no obvious deformation could be obtained by using Ektacytometer. It seems to mean that, as the suspending medium for Ektacytometric measurement, PBS would be better than PVP, especially in low shear stress area. This point of view is different from that of privous works [2] which do 1101 consider PBS as suspending medium of Ektacytometer.