Rheological and electrical properties of RBC suspensions in dextran 70. Changes in RBC morphology

Abstract

Apparent viscosity and conductivity of red blood cells (RBC) suspensions in dextran 70 (Dx 70) with various concentrations were evaluated in vitro under steady and unsteady flow conditions. Conductivity time and shear rate dependences in parallel with the rheological properties of the samples were studied under transient flow regimes at different local structure of the uniform Couette flow. Their relationships on Dx 70 concentrations were evaluated too. A concurrent measurement system, using a Contraves Low Shear 30 rotational rheometer was used in the study [1-3]. Low shear viscosity increased and conductivity decreased of RBC suspensions in dextran 70, depending on dextran concentration, compared to non-aggregating control RBC suspension in PBS. A time course of conductivity of RBC suspensions in Dx 70 was recorded under different flow conditions and provides experimental description of RBC aggregation-disaggregation processes and other cell-cell interactions. Dx 70 induces morphological alterations in RBC shape and arrangement in the suspensions. Echinocytes are observed at low Dx 70 concentrations while spherocytes are found mainly in smears at higher Dx 70 concentrations. Their morphological characteristics affect blood electrical and mechanical properties. © 2010 International Federation for Medical and Biological Engineering.