Before revision: The nonlinear elastic properties of fibrin networks are crucial for normal blood clotting . Here, we show that the extraordinary strain-stiffening response of fibrin clots reflects the hierarchical architecture of the fibrin fibers , which are bundles of wormlike protofibrils .
After revision: The nonlinear elastic properties of fibrin networks are crucial for normal blood clotting , protofibrils self-assemble and bundle to form networks of semiflexible fibers. Here we show that the extraordinary strain-stiffening response of fibrin clots reflects the hierarchical architecture of the fibrin fibers , which are bundles of wormlike protofibrils .