The molecular origins of the mechanical properties of fibrin

When normal blood circulation is compromised by damage to vessel walls, clots are formed at the site of injury. These clots prevent bleeding and support wound healing. To sustain such physiological functions, clots are remarkably extensible and elastic. Fibrin fibers provide the supporting framework of blood clots, and the properties of these fibers underlie the mechanical properties of clots. Recent studies, which examined individual fibrin fibers or cylindrical fibrin clots, have shown that the mechanical properties of fibrin depend on the mechanical properties of the individual fibrin monomers. Within the fibrin monomer, three structures could contribute to these properties: the coiled-coil connectors the folded globular nodules and the relatively unstructured αC regions. Experimental data suggest that each of these structures contributes. Here we review the recent work with a focus on the molecular origins of the remarkable biomechanical properties of fibrin clots.