Front Microrheology is a technique developed to track the velocity of the fluid-air interface inside a microfluidics channel and determine the viscosity of Newtonian and non-Newtonian fluids. 

Aggregation is a characteristic of red blood cells (RBCs), which consists in the tendency of red blood cells to form organized stacked structures named rouleaux. The formation of these structures is related to macromolecules present in plasma (i.e. fibrinogen and dextran) which increase in concentration in certain inflammatory diseases, such as, allergies and rheumatic diseases.

The rheological properties of blood depend highly on the properties of its red blood cells: concentration, membrane elasticity and aggregation. These properties affect the viscosity of blood, as well as its shear thinning behavior. Moreover, it has been demonstrated that, in some cases, these properties are related to diseases, such as hemolytic anemias.

The presence of defects and heterogeneities in different surfaces generates that a propagating fluid front (fluid-air interface) gets attached to the surface in a phenomenon known as pinning.