Figure 2.

(A) Viscosities of blood samples as a function of shear rate (WB, n = 5; 5% F70, n = 4; 10% F70, n = 5; 15% F70, n = 5). (B) Viscosities of blood samples in (A) focusing on the high-shear range for easier visualization. (C) Densities of blood samples containing different concentrations of F70. (D) Estimated ESR values calculated from the settling velocity. Settling as single cells is extremely slow regardless of the medium (WB, 10% F70, and 15% F70). However, cellular aggregation effectively increases the radius of the particle (i.e., R × 2, R × 3, etc.) and thereby greatly increases the rate of settling. (E) The computed thickness of the depletion layer on the surface of RBCs in the presence of Ficoll 70 kDa or 400 kDa polymers at a range of bulk concentrations. (F) The minimum interaction energy of Ficoll 400 kDa in a range of bulk concentrations. Negative energies are indicative of attractive forces which cause RBC aggregation. Interaction energies due to Ficoll 70 kDa are universally non-negative and are therefore not shown. (G) When samples were left undisturbed for 20 minutes, RBCs in WB formed aggregates spontaneously. RBC aggregation was greatly inhibited in the presence of 5% F70, and completely prevented in the presence of 10% and 15% F70. In contrast, RBCs aggregated immediately in the presence of 5% F400, but 15% F400 also inhibited aggregation. Scale bar represents 10 μm.