Red blood cell deformation in flows through a PDMS hyperbolic microchannel

Red blood cells (RBCs) are the major cellular component in blood and are highly deformable in their normal state. RBC deformability is important in the delivery of oxygen to the tissues and plays a major role in microcirculation. Although most studies on RBC deformability consider the effect of shear flow alone, extensionally-dominated flows are often found in the human circulatory system, namely when there is a change in the cross-sectional area, e.g. in stenoses and in the transition from vessels to catheters (Fujiwara et al. 2009). This study aims to characterize the deformation of RBCs in microfluidic extensional flows. For this purpose, we use microchannels having a hyperbolic shape in which the fluid experiences a nearly constant strain rate at the centerline of the microchannel (Oliveira et al. 2007). The deformation index (DI) measured in these experiments evidences the highly deformable nature of RBCs under strong extensional flows. References Fujiwara, H., et al., 2009, J. Biomech., 42, 838-843. Oliveira, M.S.N., et al., 2007. Exp. Fluids, 43, 437-451