Numerical simulation of rheology of red blood cell rouleaux in microchannels.

An elastic spring model is applied to simulate the skeletal structure of the red blood cell (RBC) membrane and to study the dynamical behaviors of the red blood cell rouleaux (aggregates) in microchannels. The biconcave shape of RBCs in static plasma and the tank-treading phenomenon of single RBCs in simple shear flows have been successfully captured using this model. The aggregation and dissociation of RBCs with different deformability have been investigated in both shear and Poiseuille flows by taking into consideration the rheology of the cells and the intercellular interaction kinetics. It is found that the equilibrium configuration of the rouleaux formed under no-flow condition, the motion of the rouleaux in the flows, and the rheological behavior of individual cells in the rouleaux is closely related to the intercellular interaction strength, hydrodynamic viscous forces, and the deformability of the cell membrane.