title: Inversion of hematocrit partition at microfluidic bifurcations.
abstract: Partitioning of red blood cells (RBCs) at the level of bifurcations in the microcirculatory system affects many physiological functions yet it remains poorly understood. We address this problem by using T-shaped microfluidic bifurcations as a model. Our computer simulations and in vitro experiments reveal that the hematocrit (ϕ0) partition depends strongly on RBC deformability, as long as ϕ0<20% (within the normal range in microcirculation), and can even lead to complete deprivation of RBCs in a child branch. Furthermore, we discover a deviation from the Zweifach-Fung effect which states that the child branch with lower flow rate recruits less RBCs than the higher flow rate child branch. At small enough ϕ0, we get the inverse scenario, and the hematocrit in the lower flow rate child branch is even higher than in the parent vessel. We explain this result by an intricate up-stream RBC organization and we highlight the extreme dependence of RBC transport on geometrical and cell mechanical properties. These parameters can lead to unexpected behaviors with consequences on the microcirculatory function and oxygen delivery in healthy and pathological conditions.
authors.affiliation: Laboratoire Interdisciplinaire de Physique (LIPhy) UMR5588 CNRS-Université Grenoble Alpes, Grenoble F-38041, France.
authors.forename: Zaiyi
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Laboratoire Interdisciplinaire de Physique (LIPhy) UMR5588 CNRS-Université Grenoble Alpes, Grenoble F-38041, France.
authors.forename: Gwennou
authors.initials: G
authors.lastname: Coupier
authors.affiliation: CNRS-Sorbonne University, Université de Technologie de Compiègne, UMR7338 Biomechanics and Bioengineering, 60203 Compiègne, France; Theoretische Physik I, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Badr
authors.initials: B
authors.lastname: Kaoui
authors.affiliation: Laboratoire d'Hématologie, CHU, Grenoble, France; TIMC-IMAG/TheREx, CNRS UMR5525, Université Grenoble Alpes, Grenoble, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Polack
authors.affiliation: Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, The Netherlands; Faculty of Science and Technology, Mesa+ Institute, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: Jens
authors.initials: J
authors.lastname: Harting
authors.affiliation: Laboratoire Interdisciplinaire de Physique (LIPhy) UMR5588 CNRS-Université Grenoble Alpes, Grenoble F-38041, France.
authors.forename: Chaouqi
authors.initials: C
authors.lastname: Misbah
authors.affiliation: Laboratoire Interdisciplinaire de Physique (LIPhy) UMR5588 CNRS-Université Grenoble Alpes, Grenoble F-38041, France. Electronic address: thomas.podgorski@ujf-grenoble.fr.
authors.forename: Thomas
authors.initials: T
authors.lastname: Podgorski
mesh_terms: D015415:Biomarkers / Q000097:blood; D001783:Blood Flow Velocity; D003198:Computer Simulation; D004912:Erythrocytes / Q000378:metabolism*; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008833:Microcirculation; D046210:Microfluidic Analytical Techniques; D055806:Microvessels / Q000033:anatomy & histology / Q000502:physiology*; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D012039:Regional Blood Flow; D014783:Viscosity
chemical_list: D015415:Biomarkers; D006454:Hemoglobins
keywords: Blood; Lattice Boltzmann method; Microcirculation; Microfluidics; Red blood cell