(459d) Effect of Red Blood Cell Hematocrit on Platelet Adhesion in a Microchannel: Simulations and Experiments

Authors: 
Spann, A. P., Stanford University
Fitzgibbon, S., Stanford University
Shaqfeh, E. S. G., Stanford University

Due to differences in size and deformability of red blood cells versus platelets, the volume fraction (hematocrit) of red blood cells in a capillary affects the degree to which platelets are able to marginate to the proximity of a vessel wall and, and thereafter engage in the formation of a thrombosis. In this work we use both simulations and experiments to investigate the relationship between red blood cell hematocrit and platelet adhesion activity.  We perform experiments where blood flows through a microfluidic channel coated with von Willebrand factor and we observe the rate at which platelets adhere to the wall at varying hematocrit.  The results are compared with 3D boundary integral simulations of a suspension of red blood cells and platelets in a periodic channel with a kinetic model for platelet binding.  In both experiments and simulations, we find that the rate of platelet adhesion varies greatly with red blood cell hematocrit. Moreover, at very reduced hematocrit, essentially platelet binding is not measured.  We observe that the relative decrease in platelet activity in response to decreased hematocrit is quantitatively and qualitatively similar profile for simulation and experiment.