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Biomimicking red blood cell filtration by the spleen
Blood circulation in our vascular system is a physical tour de force. To distribute oxygen throughout the body, Red blood cells (RBCs) continuously travel through the microcirculation, through thin capillaries that are smaller than their size, and are thus highly deformable. Their deformability is periodically monitored by the spleen : when too rigid and unable to pass through the inter-endothelial splenic slits (IESs) of submicron width, RBCs are trapped in the spleen and destroyed. Today, due to lack of suitable in vitro devices and validated computational approaches, the mechanisms of RBC filtration by the IESs are still poorly understood. Here, by combining biomimicking experimental measurements and quantitative numerical simulations we elucidate the mechanisms of passage of RBCs through IESs.
We developed a microfluidic device containing high aspect ratio slits (2-µm long, 5-µm high, < 1-µm wide), reproducing the physiological dimensions of the IESs [1] and validated a numerical model of RBCs passing through splenic-like slits [2]. We couple these approaches to understand retention rates, transit times and cell deformations of RBCs squeezing in splenic-like slits as a function of external parameters (slit dimensions, pressure drop, temperature).
[1] P. Gambhire et al. Small 13, 1700967 (2017)
[2] H. Lu and Z. Peng. Physics of Fluids 31, 031902 (2019)
