Fracture mechanics of blood clots: Measurements of toughness and critical length scales

Abstract

Blood clots are naturally derived bioadhesives that adhere to tissues, plug vascular damage and stop bleeding. Their function of hemostasis hinges on their resistance against rupture (toughness). Despite the relevance, fracture mechanics of blood clots remains largely unexplored, particularly the toughness and critical length scales governing clot fracture have not been reported. Here, we study the fracture behavior of human whole blood clots and platelet-poor plasma clots. The fracture energy of whole blood clots and platelet-poor plasma clots determined using modified lap-shear method is 5.90 ± 1.18 J/m2 and 0.96 ± 0.90 J/m2, respectively. We find that the measured toughness is independent of the specimen geometry and loading conditions. These results reveal an important contribution of blood cells to the clot fracture, as well as the dissipative length scale and nonlinear elastic length scale governing clot fracture. This study will motivate the investigation on blood clot fracture and inspire the development of clot-mimicking bioadhesives.