Microrheology of 2D-Actin networks

Actin is a protein found in all eukaryotic cells; mainly it occurs as the major component in the cells’ cytoskeleton and cortex, also it participates in cell movement processes.

In this project we study visco-elastic properties of reconstituted “artificial” actin cortex. In order to obtain a structure, that would be analogous to the cell cortex and mimicking its structure, we attach actin filaments to lipids lining the surface of an oil droplet using biotin-streptavidin bonds (on the picture: filaments are blue, streptavidin is red; lipids are not shown); in this way they form a very thin actin network that could be visualized and studied by confocal microscopy. To measure the visco-elastic properties of this reconstituted actin cortex, we use microrheology based on multi-particle tracking, which allows extracting storage and loss moduli from the mean square displacement of the traced particles moving in the cortex.  This approach allows incorporating different actin-binding proteins or even motor proteins into this “2D-network” with an opportunity to quantitatively characterize their effect on the mechanical properties of the actin cortex.