The Role of Thrombin, Fibrinogen, and Fibronectin on Platelet Clot Retraction Forces Analyzed Using Microposts

When a blood vessel is damaged, platelets aggregate together to form a thrombus that seals vascular leakage and promotes healing. The process of thrombosis involves activation of platelets by soluble ligands, adhesion to the wound site, change in shape from a discoidal to a stellate structure, and the attachment of additional platelets onto the nascent clot through adhesive ligand bridges. Once formed, a clot will undergo a retraction in volume that packs platelets together and allows blood flow to recommence. Much attention has been paid to the early phases of thrombosis — adhesion and aggregation — but the process of clot retraction is vital to stabilizing the clot.