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Visitor Project: Microcirculatory dynamics of blood

Starting: June 2014

 

The capacity of blood to correctly irrigate organs and supply oxygen and nutrients strongly depends on the mechanical properties of red blood cells (shape, elasticity), which can be altered by specific hemopathologies such as sickle cell anemia, elliptocytosis or thalassemia.

The project aims at understanding the dynamics of red blood cells in micro-flows which are representative of the in-vivo microcirculation, from a simple capillary to a complex network of channels where many hydrodynamic phenomena are coupled.

In shear flows for instance, red blood cells show a rich variety of dynamical behaviours influencing the rheological properties of blood. In this project, the focus is on the rheology of erythrocyte suspensions subjected to an oscillatory shear rate superimposed on a constant shear rate, a generic situation in blood circulation where the viscoelasticity of the red blood cell is excited about a non equilibrium state.

This fundamental knowledge base could inspire the development of medical devices for diagnosis and treatment.

The mechanisms leading to an inhomogeneous structure of the blood cell suspension at the channel scale is investigated, as well as the rheology and flow properties in model microvascular networks at a larger scale.

A particular focus is devoted to the influence of mechanical alterations of the cells on these phenomena, in an effort to understand the consequences of related pathologies. In this perspective, the role of the endothelial layer is also considered because of its known importance in cardiovascular diseases, along with the aggregation properties of red blood cells.


Monitoring of the red blood cells repartition in a microfluidic network (the stream runs from the top of the photo) and view of the erythrocyte volume fraction (haematocrit) in the same device (higher EVF appear in red). Credit: T. Podgorski

The project includes a fundamental questioning on the dynamics and rheology of healthy and pathological cells, and applicative goals through the identification of the key mechanical factors affected by blood cell pathologies, the development of diagnostic tools and the design of microfluidic devices for the sorting and separation of cells according to their mechanical properties.

 

This project involves a collaboration between the laboratory LiPhy, the University Hospital of Grenoble, the French Blood Bank and the Bulgarian Academy of Sciences.

 

PI: Thomas Podgorski; Co-PI: Victoria Vitkova (visitor)

 


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