Understanding margination, from vessels to vascular networks

Host laboratory and collaborators

Marc Leonetti / CINAM / marc.leonetti@cnrs.fr

Marc Jaeger / M2P2 / marc.jaeger@centrale-marseille.fr

Annie Viallat / CINAM / viallat@cinam.univ-mrs.fr


Margination corresponds to a key step for efficient body response to injury or sepsis in which leucocytes and platelets migrate to the edges of blood vessels. This process enhances rolling for example. In physics, margination seems similar as a segregation of leucocytes according to RBCs which flow at the center of vessels. Without flow, there is no margination. Such a segregation also appears in flowing granular media with different sizes of particles. However, cells and vessels’ walls are soft and so experience hydrodynamic interactions of a different kind. Another open issue is the nature of margination in a microvascular network. Indeed, at each bifurcation, the pattern of margination is broken and must be re-established. We will use fast confocal microscopy and microfluidics (design of soft microchannels and soft networks) to decipher the origin of margination and its map.


blood, margination, vascular network, suspensions, rheology, out-of-equilibrium


The first one is to achieve to a clear explanation of margination. What does depend on biology according to physics ? Are the softness-driven hydrodyanmic interactions the salient feature of margination ? What is its efficiency according to the cell type ? How long does the margination take to establish ? Is there a relation between the tortuosity and the topogogy of the network and the map of margination ? Can we define network weakness in terms of body response ? Another objective is to be quantitative and to use cells and not artificial systems. Finally, a comparison with theory and numerics by MJ is expected.

Expected profile

As the 3 supervisors are complementary (AV=exp,ML=exp/theory,MJ=num/theory), we seek an experimentalist with a knowledge in microfluidics to be efficient quickly. Any experience in biofluids or soft matter (gel, suspension) will be an advantage. The candidate shall be able to perform own programs to control several devices simultaneously.

Is this project the continuation of an existing project or an entirely new one?

The supervisor was the PI of the now finished ANR « Polytransflow » with IPBS and IMRCP which enabled the experimental approach using biomimetic systems far from equilibrium (polymersomes). This ensures a quick start-up.

2 to 5 references related to the project

  • Quantifying platelet margination in diabetic blood flow, H-Y Chang et al, Biophys. J 115 (2018); Influence of erythrocyte aggregation on leukocyte margination in postcapillary venules of rat mesentery, MJ Pearson et al, Am. J. Physiol 279 (2000);
  • Molecular mechanisms of leukocyte recruitment in the inflammatory, K.Ley, Cardiovasc. Res 32 (1996)

3 main publications from each PI over the last 5 years

  • J. Dupire, P.-H. Puech, E. Helfer and A. Viallat, Mechanical adaptation of monocytes in model lung capillary networks, PNAS 30 (2020)14798-14804
  • A. Viallat and M. Abkarian, Dynamics of blood cell suspensions in microflows, CRC 2020
  • S. Atwell, C. Badens, A. Charrier, E. Helfer, A. Viallat, Dynamics of individual red blood cells under shear flow: a way to discriminate deformability alterations, Frontiers in Physiology 2406 (2022)
  • K. Xie, C. de Loubens, F. Dubreuil, DZ Gunes, M. Jaeger, M. Leonetti, Interfacial rheological properties of self-assembling biopolymer microcapsules, Soft Matter 13 (2017)
  • R. Chachanidze, K. Xie, H. Massaad, D. Roux, M. Leonetti, Structural characterization of the interfacial self-assembly of chitosan with oppositely charged surfactant, J. Colloid Interf. Sci. (in press, online 5 february)
  • M. Maleki, C. de Loubens, H. Bodiguel, M. Leonetti, Membrane emulsification for the production of suspensions of uniform microcapsules with tunable mechanical properties, Chem. Eng. Sci. 237 (2021)
  • J. Lyu, P.G. Chen, G. Boedec, M. Leonetti, M. Jaeger, hydrid continuum-coarse-grained modeling of erythrocytes, CRAS 346 (2018)
  • S. Das, M. Jaeger, M. Leonetti, R.M. Thaokar, P.G. Chen, Effect of pulse width on the dynamics of a deflated vesicle in unipolar and bipolar pulsed electric fields, Phys. Fluids 33 (2021)