The influence of biomechanical parameters of an erythrocyte and viscosity of the surrounding fluid on the hydrodynamic interaction with a solid wall

Abstract

The nature of  blood flow in capillaries, arterioles, and venules largely depends on the mechanical interactions between red blood cells and vessel walls . A theoretical understanding of the principles of hydrodynamic interaction between blood cells and vessel walls is essential for a comprehensive biophysical description of blood flow in the microcirculatory system, as well as for the design of medical microfluidic devices for processing blood samples. In this study, numerical methods are used to investigate the behavior of a single red blood cell (erythocyte) near a solid flat surface under conditions of shear flow of a viscous Newtonian fluid. The aim of the study is to identify the pattern of erythrocyte motion depending on its biomechanical parameters and hydrodynamic conditions. To address these issues, we use a numerical model that combines particle dynamics and the Lattice Boltzmann method with the Bhatnagar-Gross-Krook collision integral. The biomechanical model of the red blood cell takes into account tensile and bending elasticity, as well as the forces that maintain the membrane area and the cell volume. Computer simulation of red blood cell trajectories under various hydrodynamic conditions shows that the velocity of cell repulsion from a solid wall is linearly dependent on the shear rate. It varies non-monotonically as the red blood cell moves away from the wall, and decreases at greater distances. The lift effect in the model is most pronounced when the red blood cell moves in a “tank-treading” mode at high shear stresses. The dependence of the lift velocity on the  elasticity and volume of the cell is quantified by varying the biomechanical parameters of the erythrocyte.