Flow properties of microcapsule suspensions as a model of blood

Abstract

Model red blood cells containing aqueous sheep hemoglobin solution within semipermeable poly (phthaloyl l-lysine) membrane are prepared and suspended in isotonic buffer solutions of different pH at volume concentrations of 20, 30 and 40 per cent. Suspensions of sheep red blood cells in the same isotonic buffer solutions at the same volume concentrations are also prepared.

The flow properties of the above model and sheep red blood cell suspensions are measured by a capillary viscometer and compared with each other. The effect of dextran added to the suspension medium on the flow properties of the both suspensions is detected. The effects of the pH of the suspension medium on the viscosity of the model suspension is also measured. The shear stress versus shear rate relations for both of the model and sheep erythrocyte suspensions are found in accord with the Casson equation. The dependence of the relative viscosity on the particle concentration is expressed by an empirical relation: $\mathit{\eta }=1+\mathit{a}\mathit{\varphi }+\mathit{b}{\mathit{\varphi }}^2+\mathit{c}{\mathit{\varphi }}^3$ for the both suspensions in the same isotonic buffer solution.

The result shows that the model suspension can serve as a model for blood in the sense of first approximation.