Depletion Layer and Viscosity of Microfluidic Flow with Aggregating Red Blood Cells

In blood flow, many different kind of large proteins in the blood plasma induce attraction between red blood cells (RBCs) that results in aggregates known as rouleaux. To understand how polymer additives affect the aggregate structure of RBCs and blood viscosity, several experiments have probed the effects of polymers such as dextran or polyethylene oxide on RBC microstructures. A few studies have shown that the RBC aggregation size increases with the increase of the polymer concentration and reaches a maximum at higher polymer concentration.

In this study, we use the lattice Boltzmann method coupled with the coarse-grained spring network model for RBCs to simulate aggregating RBCs in a rectangular microchannel under Poiseuille flow. The effect of polymer additives is modeled by an attractive potential. We investigate the cell free layer thickness, the aggregate size and distribution, as well as the suspension viscosity in various shear rates and different strength of the attraction interaction.