Dr. Chaouqi Misbah "The Everyday Life of Blood Cells: Swept Away by the Current or Swim"

The seminar will discuss some general results  of blood cells (like red blood cells-RBC- and leukocytes) under flow. Regarding  flow of RBCs we will present two major results: (i)  blood cryslas (organisation of RBC in a crystalline structure under shear flow), (ii) analogy between blood flow and traffic flow. Leukocyte, traditionally believed to crawl on a substratum, can swim in a very efficient way. Their swimming is qualified as amoeboid. A minimal model will be presented that captures several features of amoeboid swimming. It is found that confinement drastically affect swimming and a straight trajectory  is always unstable in favor of navigation. This persistent navigation  may be an indication that leukocytes have the ability of flexibly navigate through any organ without adaptations to alternating extracellular ligands, which would constitute a big constraint against an efficient immune surveillance. Finally, it will be shown that a condition of an optimal swimming reproduces the behavior of other real swimmers (like Eutreptiella gymnastica).
 

invited by Falko Ziebert