Mechanical properties of blood clots - a new test method

A blood clot needs to have the right degree of mechanical, chemical and biological properties to stem the flow of blood and yet to be suitable for lytic enzymes or mechanical thrombectomy so as not to form a thrombotic event. The origin and understanding of these mechanical properties are still unknown. Clots are made of a threedimensional network of fibrin fibers stabilized through ligation with a transglutaminase, factor XIIIa. New methods to achieve information about the in-situ mechanical properties were established. We performed compressive strength experiments of aged human blood clots. After the set up of a new test environment, we were able to perform in-situ tensile strength measurements of aged animal and human blood clots. Stress strain curves of aged clots were measured and discussed. The viscoelastic properties of the clot material were quantitatively described. This work should finally give a better understanding of the behaviour of aged blood thrombus bulk material and induced mechanical stress.