Red blood cell motions in high-hematocrit blood flowing through a stenosed microchannel

We investigated the behaviour of red blood cells (RBCs) in a micro-channel with stenosis by using a confocal micro-PIV system. We could successfully measure individual trajectories of RBCs in a concentrated suspension up to 20% hematocrit (Hct). The results show that the trajectories of healthy RBCs become asymmetric before and after the stenosis, though trajectories of tracer particles in pure water are almost symmetric. The asymmetry is larger in a 10% Hct case than in a 20% Hct case. We also investigated the effect of deformability of RBCs on the trajectories by hardening RBCs by glutarardehyde treatment. The results indicate that the deformability is the key factor in the asymmetry of trajectories and the thickness of cell-free layer. We think that the present results give fundamental knowledge for better understanding blood flow in microcirculations