A highly collaborative study for providing new guidelines
Seven French laboratories shared their know-how to answer a methodological question: how should blood samples be stored and prepared so that the mechanical response of red blood cells is as close as possible to the physiological response?
This collaborative work was realized with the support of GDR Mécabio, now GDR Mécabio-Santé
A strong link between structure and viscosity
We used red blood cells as model deformable particles to explore the rheology of a confined suspension of such particles. In conditions where strong structuring effects take place due to confinement, the evolution of the effective viscosity with particle concentration shows a remarkable succession of ranges of rapid growth and plateaus that are associated to qualitative transitions in the structure of the suspension.
Looking for the origin of the depletion layer
200 years ago, Poiseuille observed for the first time the
presence of depleted layers in the vicinity of the walls of
blood vessels. Through in-vitro experiments, we have
characterised the migration mechanism that is at the origin
of this phenomenon.
Microvasc. Res. 124, 30 (2019)
Considering a bolus of red blood cells, the dispersion in initial lateral positions, which may be reinitialised at bifurcations, induces strong dispersion in the residence times within an organ. Phys. Rev. Fluids 8, 043102 (2023)
a signature of their discreet diversity
Red blood cells have a subtle mechanics which is not fully described yet by current models. We have carried out an extensive experimental study of their dynamics under shear flow, which is very sensitive to their intrinsic properties - that vary from one cell to another. This constitutes a reference work for the validation of new models.
Inversion of the usual separation law at low hematocrits
At the level of a bifurcation where the flows split unequally, red blood cells flow in such a way that the cell concentration often increases in the high flow rate branch. This splitting strongly depends on the upstream organization of the cell suspension. In some cases (high confinement and low concentration), a reverse effect is observed.
Plasma proteins cause red blood cells to form clusters called rouleaux which are usually assumed to be disaggregated in the circulation due to shear forces. However, despite the large shear rates present in microcapillaries, the presence of either fibrinogen or the synthetic polymer dextran leads to an enhanced formation of robust clusters.
These clusters are initiated by hydrodynamic interactions, which also contribute to their stabilization, in parallel to the adhesion-induced stabilization.
CNRS Researcher @ LIPhy
orcid.org/0000-0001-5010-4148