Viscoelastic properties of sickle cells and hemoglobin.

The quantitative relationship between deoxygenation and rheological behavior of SS cell suspensions and concentrated HbS solutions has been studied under steady shear (viscosity eta) and oscillatory shear (complex viscosity with viscous component eta' and elastic component eta"). decrease of O2 saturation below 80-85% causes eta, eta' and eta" to increase progressively in SS cell suspensions and HbS solutions. These rheological parameters do not change in AA cell suspensions and HbA solutions following deoxygenation. The deoxygenation-induced increase in eta" of HbS solutions from the unmeasurable level when oxygenated reflects the gelation of HbS. At high O2 saturations, the rheological behavior of the intracellular fluid has relatively insignificant contribution to that of the SS cell suspension. As O2 saturation decreases, the viscoelastic properties of the SS cell suspension become increasingly dominated by that of the intracellular HbS. at a given degree of deoxygenation, eta, eta' and eta" of HbS solutions decrease with increasing shear rate, indicating that HbS aggregates can be dispersed by shear stress.