Probing contraction of blood clots under flow

Blood clots are active material involved in physiologic and pathologic processes. Clotting disorders prevent body's natural ability to achieve hemostasis and lead to bleeding, stroke, or heart attack. Upon injury, platelets aggregate to form blood clots that undergo contraction to stem blood flow from a vessel. The contraction is driven by collective behavior of platelets extending filopodia to impose contractile forces on the fibrin scaffold, leading to drastic changes in clot volume and elastic modulus. Clot contraction happens inside blood vessel and it has been shown that RBCs and flow have substantial influence on the mechanical properties and contraction process of blood clots. Understanding the biophysical mechanism of clot contraction within blood flow is critical for the development of new diagnoses and treatments for bleeding disorders and thrombotic disorders. We integrate RBCs and flow with our validated mesoscale platelet-fibrin clot contraction model. We evaluate the effects of RBC concentration, flow velocity, and how fibrin clot is bounded by vessel on the macroscale biomaterial properties and contraction dynamics of blood clots. We probe the effect of clot contraction on RBC shape and ability to remain within clot and the effect of clot contraction on flow.