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Accueil > Séminaires > Archives > Archives 2014

An experimental approach to blood flows : lift, diffusion and clustering

Gwennou Coupier, Laboratoire Interdisciplinaire de Physique (LIPhy). Université Joseph Fourier

par Salmon Jean-Baptiste - publié le , mis à jour le

Blood is a complex fluid, a property that stems from the presence of
deformable cells, mainly red blood cells, and plasma proteins. The peculiar
properties of blood comes from the complex mechanical response of the cells
to external flow but also to their ability to migrate transversally to flow
direction, which leads to an inhomogeneous structure of the suspension, at
the local scale but also within the whole capillary network.

I will present a set of experiments that combine basic microfluidic approach
with more specific techniques such as digital holography or microgravity
environment. I will first describe how cells are lifted up far the channel
walls. This results in concentrating the cells in the center of the
channels, a phenomenon that is counterbalanced by hydrodynamic interactions
between them. The cumulative effect of these interactions is a non-linear
and anisotropic shear-induced diffusion.
These hydrodynamic effects directly influence blood structure and rheology
but also how it splits at bifurcations. I will finally discuss the
contribution of the short-range adhesion forces between cells due to the
presence of proteins in the plasma. It was recently found that this
contribution is fundamental in the narrow channels of the capillary network.