Human blood plasma in capillary-size flow: Revealing hidden elasticity and scale dependence

The dynamical mechanical analysis of blood generally uses models inspired by conventional flows, assuming scale-independent homogeneous flows and without considering fluid-surface boundary interactions. The present experimental study highlights the pertinence of a non-conventional approach to identify dynamic properties of human blood plasma. A finite shear elastic response (solid-like property) is identified in nearly static conditions, which also depends on the scale (being reinforced at small scales). Therefore, blood plasma is a scale dependent viscoelastic solid that flows over a weak stress threshold. This finding opens new routes for medical diagnosis and device fabrication