Experimental evaluation of mechanical and electrical properties of RBC suspensions in Dextran and PEG under flow II. Role of RBC deformability and morphology

Abstract

Mechanical and electrical properties of the normal RBCs suspensions and of hardened after treatment with glutaraldehyde (0.01-2.5%) RBCs in isotonic physiological solution and Dextran 70,000 (Dextran 70) and Polyethylene glycol 35,000 (PEG) and adjusted to hematocrit of 40%, were evaluated. Apparent viscosity and conductivity were measured under steady and transient flow regimes at low shear rates and at different local structure of the flow at 37 °C. A time course of conductivity was recorded in parallel with the rheological properties of the RBC suspensions and conductivity and apparent viscosity dependences on shear rates were studied and compared at different concentrations of Dextran 70, PEG and glutaraldehyde. Low shear viscosity decreased after RBCs treatment with glutaraldehyde and at 0.5-2.5% it is constant. Echinocytes are observed at low Dextran 70 and PEG concentrations while spherocytes are found mainly in smears treated with higher concentrations. The results show that the apparent viscosity and conductivity of RBCs suspensions in Dextran 70 and PEG are strongly influenced by flow, shear rates, concentration, cell deformability and morphology and the method is sensitive to study the mechanical and electrical properties of RBC suspension and to provide experimental description of RBCs and other cell-to-cell interactions.