Fig. 4.

Rheology of dense suspensions of RBCs ($Ht=45\%$). (A) Relative viscosity of the suspensions of deformable RBCs in plasma (red) and in PBS/BSA (yellow) as a function of $\dot{\gamma }$ in comparison with the suspensions of washed cells hardened at rest (green) and at $\dot{\gamma }=1,500$ s⁻¹ (blue). Suspensions of deformable RBCs show a typical shear thinning for increasing $\dot{\gamma }$, whereas hardened samples have a nearly Newtonian behavior. SDPD simulation data (black stars) are also shown for deformable cells and agree well with the experimental results for RBCs suspended in plasma or in PBS/BSA. (B) Rheology of washed blood in comparison with the suspensions of RBCs in solutions with different dextran concentrations (temperature = 25 °C). (Inset) The effect of viscosity ratio $\lambda$ is highlighted by the illustration of single cells flowing in both PBS/BSA and dextran solutions in microfluidics at a comparable shear stress $\tau$. (Scale bars, 5 $\mu$m.)