Dresden 2017 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 12: Focus: Soft Particles in Flows II (joint focus session CPP/DY)

CPP 12.7: Talk

Monday, March 20, 2017, 17:00–17:15, ZEU 160

Red blood cells dynamics in biomimetic submicron splenic slits — •Annie Viallat¹, Emmanuele Helfer¹, Anne Charrier¹, Priya Gambhire¹, Scott Atwell¹, Catherine Badens², and Cecile Iss¹ — ¹Aix Marseille Univ, CNRS CINAM, Marseille, France — ²Aix Marseille Univ., INSERM, GMGF, Marseille, France

In drug delivery, cancer cell dissemination and red blood cells (RBCs) splenic filtration, nanoparticles and cells have to deform and pass through the submicron and high aspect ratio gaps between the endothelial cells lining blood vessels. The dynamics of passage of particles/cells remain poorly understood because costly technologies are required to reproduce gaps of physiological dimensions in devices suitable for in-vitro optical-microscopy observations. Here, novel microfluidic PDMS devices containing high aspect ratio slits with submicron width were molded on silicon masters by using a simple, inexpensive, and highly flexible combination of standard UV lithography and anisotropic wet etching. These devices revealed novel modes of deformations of healthy and sick RBCs squeezing through slits replicating splenic slits (0.8x2x5 microns) under physiological interstitial pressures. At the slit exit the cytoskeleton of spherocytic RBCs was spectacularly detached from the lipid membrane whereas RBC shapes from healthy donors and patients with sickle cell disease exhibited peculiar tips at their front. These tips disappeared much slower in patients cells, allowing to estimate a threefold increase in RBC cytoplasmic viscosity in sickle cell disease. Measurements of both time and rate of RBC sequestration in the slits allowed quantifying the massive spherocytic RBCs trapping.