Active matter is characterised by persistent out-of-equilibrium behaviour, lack of detailed balance and of time-reversal symmetry, nonlinearity, and multibody interactions.
Blood is a very special fluid, consisting of blood cells and plasma. Its motion and flow properties are governed by the elasticity of the cells and their interactions.
The motion of biological (e.g. bacteria, sperm, algae) and synthetic (e.g. nanorods, Janus colloids) microswimmers is governed by low Reynolds-number hydrodynamics.
Cells are complex micromachines, with an active cytoskeleton and many metabolic processes. They excert forces on their environment, migrate, and react to external stimuli.
