Effect of Mechanical Strain on the Degradation of Fibrin Gel and Its Rheology

Fibrin plays an essential role in forming the structural support of a blood clot. Fibrin network

formation is promoted by the enzyme thrombin, which activates fibrinogen to become

self-assembling fibrin monomers, whereas the enzyme plasmin disintegrates fibrin polymers and is necessary

for the removal of clots. Within the body, clots frequently experience various forms of

mechanical strains. Therefore, understanding how mechanical strains, such as stretching and

compression, affect the degradation of fibrin is important. The goal of our study is to explore the

rheological consequence of stretching and compressing fibrin gels when subjected to plasmin

degradation. Our rheological measurements show that the shear storage modulus of a fibrin gel

incubated with plasmin when stretched by 20% decreases about 1.5 times faster than that of a

relaxed gel, but the compressed gels, also of 20% strain, degrade 0.6 times slower. Understanding

the origin of these findings would advance our understanding of how an enzyme’s activity can be

altered by mechanical strain of its substrate and provide insight into homeostatic control of blood-clotting.