Numerical analysis for elucidation of mechanical interaction between an erythrocyte moving in medium subject to inclined centrifugal force and endothelial cells on a plate

Elucidation of the mechanical interaction between an erythrocyte and an endothelial cell is an important issue that may lead to clarification of mechanisms of cardiovascular diseases and development of new treatments. In order to clarify the interaction, frictional characteristics of erythrocytes moving on various plates have been measured using an inclined centrifuge microscope. The objective of this study was to clarify the mechanical interaction between an erythrocyte moving in medium subject to inclined centrifugal force and endothelial cells on a plate. Three-dimensional (3D) analysis was performed with contact force models between an erythrocyte and glycocalyx on the surface of endothelial cells and two-dimensional (2D) analysis was conducted using a lubrication theory for compressible porous media and a simple erythrocyte model. In the 3D analysis, two contact force models were adopted in which shear stresses acting on the bottom surface of an erythrocyte varied proportional or inversely proportional to the distance to the base plate. As a result, the experimental frictional characteristics for an endothelia-cultured plate were properly reproduced by the inverse proportion model. In the 2D analysis using the lubrication theory, the result without the porous media qualitatively agreed with those of the experiment for the plain and material-coated plates and that of the 3D analysis without contact force models, whereas the result with the porous media was qualitatively different from those of the experiment and the 3D analysis.