Mechanics of the red blood cell network

Changes in the microstruture of blood caused by the red blood cell aggregation phenomenon affect the mechanical properties of the fluid. This fact has been extensively investigated in the past and it has been verified that the formation of rouleaux (the characteristic coin-pile like structures) and aggregates at low shear rates affect the flow and as a consequence the viscosity of the fluid is elevated. At physiological red blood cell concentrations and at low shear rates, however, in addition to rouleaux and aggregate formation an extended network is observed. The effects of network characteristics on the mechanical properties of blood have received relatively little attention in the literature and only a few studies provide quantitative data on this aspect of the blood flow. Quantitative data on network characteristics in view of the aggregation phenomenon illustrate that indeed different network configurations have different effects on the mechanical properties of the fluid. In this work, it is shown that changes in the viscosity of blood at specific flow conditions correlate with the changes in the mechanical characteristics of the red blood cell network.