title: Nano-thrombelastography of fibrin during blood plasma clotting.
abstract: Hemostasis is a complex process that relies on the sensitive balance between the formation and breakdown of the thrombus, a three-dimensional polymer network of the fibrous protein fibrin. Neither the details of the fibrinogen-fibrin transition, nor the exact mechanisms of fibrin degradation are fully understood at the molecular level. In the present work we investigated the nanoscale-changes in the viscoelasticity of the 3D-fibrin network during fibrinogenesis and streptokinase (STK)-induced fibrinolysis by using a novel application of force spectroscopy, named nano-thrombelastography. In this method the changes in the bending of an oscillating atomic-force-microscope (AFM) cantilever in human blood-plasma droplet were followed as a function of time. Whereas the global features of the time-dependent change in cantilever deflection corresponded well to a macroscopic thrombelastogram, the underlying force spectra revealed large, sample-dependent oscillations in the range of 3-50nN and allowed the separation of elastic and viscous components of fibrin behavior. Upon STK treatment the nano-thrombelastogram signal decayed gradually. The decay was driven by a decrease in thrombus elasticity, whereas thrombus viscosity decayed with a time delay. In scanning AFM images mature fibrin appeared as 17-nm-high and 12-196-nm-wide filaments. STK-treatment resulted in the decrease of filament height and the appearance of a surface roughness with 23.7nm discrete steps that corresponds well to the length of a fibrinogen monomer. Thus, the initial decay of thrombus elasticity during fibrinolysis may be caused by the axial rupture of fibrin fibers.
authors.affiliation: Department of Biophysics and Radiation Biology, and MTA-SE Molecular Biophysics Research Group, Semmelweis University, 1094 Budapest, Tűzoltó u. 37-47, Hungary.
authors.forename: Tímea
authors.initials: T
authors.lastname: Feller
authors.affiliation: Department of Biophysics and Radiation Biology, and MTA-SE Molecular Biophysics Research Group, Semmelweis University, 1094 Budapest, Tűzoltó u. 37-47, Hungary.
authors.forename: Miklós S Z
authors.initials: MS
authors.lastname: Kellermayer
authors.affiliation: Department of Biophysics and Radiation Biology, and MTA-SE Molecular Biophysics Research Group, Semmelweis University, 1094 Budapest, Tűzoltó u. 37-47, Hungary. Electronic address: kiss.balazs@med.semmelweis-univ.hu.
authors.forename: Balázs
authors.initials: B
authors.lastname: Kiss
mesh_terms: D001777:Blood Coagulation; D004548:Elasticity; D005337:Fibrin / Q000032:analysis* / Q000378:metabolism*; D005342:Fibrinolysis; D006801:Humans; D018625:Microscopy, Atomic Force / Q000379:methods*; D036103:Nanotechnology / Q000379:methods; D013300:Streptokinase / Q000378:metabolism / Q000493:pharmacokinetics; D013916:Thrombelastography / Q000379:methods*
chemical_list: D005337:Fibrin; D013300:Streptokinase
keywords: Atomic force microscopy; Elasticity; Fibrin; Streptokinase; Thrombelastography; Thrombolysis