Background: Blood clots perform the mechanical task of stemming the flow of blood. Objectives: To advance understanding and realistic modeling of blood clot behavior we determined the mechanical properties of the major structural component of blood clots, fibrin fibers. Methods: We used a combined atomic force microscopy (AFM)/fluorescence microscopy technique to determine key mechanical properties of single crosslinked and uncrosslinked fibrin fibers. Results and conclusions: Overall, full crosslinking renders fibers less extensible, stiffer, and less elastic than their uncrosslinked counterparts. All fibers showed stress relaxation behavior (time-dependent weakening) with a fast and a slow relaxation time, 2 and 52 s. In detail, crosslinked and uncrosslinked fibrin fibers can be stretched to 2.5 and 3.3 times their original length before rupturing. Crosslinking increased the stiffness of fibers by a factor of 2, as the total elastic modulus, E0, increased from 3.9 to 8.0 MPa and the relaxed, elastic modulus, E∞, increased from 1.9 to 4.0 MPa upon crosslinking. Moreover, fibers stiffened with increasing strain (strain hardening), as E0 increased by a factor of 1.9 (crosslinked) and 3.0 (uncrosslinked) at strains ε > 110%. At low strains, the portion of dissipated energy per stretch cycle was small (< 10%) for uncrosslinked fibers, but significant (approximately 40%) for crosslinked fibers. At strains > 100%, all fiber types dissipated about 70% of the input energy. We propose a molecular model to explain our data. Our single fiber data can now also be used to construct a realistic, mechanical model of a fibrin network. © 2010 International Society on Thrombosis and Haemostasis.
CITATION STYLE
Liu, W., Carlisle, C. R., Sparks, E. A., & Guthold, M. (2010). The mechanical properties of single fibrin fibers. Journal of Thrombosis and Haemostasis, 8(5), 1030–1036. https://doi.org/10.1111/j.1538-7836.2010.03745.x
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