Blood microcirculation: how to prepare your in-vitro experiments?

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

Biophys. J., 122, 360-373 (2023).

Rheology of a confined suspension

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.

Phys. Fluids 34, 042013 (2022).

Quantification of the lateral migration of red blood cells

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)

Dynamics of red blood cells

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.

J. Fluid Mech. 864, 408 (2019)

Phase separation of blood at bifurcations

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.

Microvasc. Research 105, 40 (2016)

Protein-induced clustering of red blood cells in microcapillaries

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.

Sci. Rep. 4, 4348 (2014)

These clusters are initiated by hydrodynamic interactions, which also contribute to their stabilization, in parallel to the adhesion-induced stabilization.

Soft Matter 12, 8235 (2016)