A Comparative Approach to Measure Elasticity of Whole Blood by Small Amplitude OscillationUrsula Windberger1*, Birgit Stoiber1, Christina Pöschl1 and René van den Hoven2
- *Corresponding Author:
- Ursula Windberger
Decentralized Biomedical Facilities
Department Biomedical Research
Borschkegasse 8a, 1090 Vienna, Austria
E-mail: [email protected]
Received date: November 18, 2016; Accepted date: December 23, 2016; Published date: December 31, 2016
Citation: Windberger U, Stoiber B, Pöschl C, van den Hoven R (2017) A Comparative Approach to Measure Elasticity of Whole Blood by Small Amplitude Oscillation. Rheol: open access 1:103.
Copyright: © 2017 Windberger U, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
In the past, mammalian blood was characterized by flow curves to calculate the dynamic shear viscosity of blood. It was found out that whole blood viscosity (WBV) is very divers among the animal kingdom, predominantly at low shear stresses that allow red blood cell (RBC) aggregation. RBC aggregation might be the most significant factor for blood elasticity as well. To verify this hypothesis, we tested whole blood from species with high (horse), medium (man) and low (sheep) RBC aggregability by small amplitude oscillation in CSS-mode. Blood samples were hematocrit (HCT) adjusted (40%, 50%, 60%) and tested at 7°C, 22°C and 37°C. Storage modulus (G´) increased with RBC aggregability and HCT, but decreased with temperature, as expected. Interestingly, the gradient of the G´-increase with HCT was species-specific. The lower dependency of G´ on the equine HCT value could be a benefit during physical performance when high numbers of RBCs are released from the spleen. In sheep, a HCT-threshold had to be overcome before elasticity of the blood sample could be measured, suggesting that the cohesive forces between RBCs, and between RBCs and plasma molecules must be very low. The frequencies for tests under quasi-static condition were in a narrow range around the physiologic heart rate of the species. In horse, time-dependent influences concurred at frequencies lower than 3 rad.s-1 probably due to sedimentation of RBC aggregates. In conclusion, elasticity of blood depends not only on the amount of blood cells, but also on their mechanical and functional properties.