Insights into fibrinogen mechanics under cyclic high-strain loading.
Mayar Tarek Ibrahim1, Sajjad Norouzi1, Uma Paul1
1Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas.
Biophysical Journal
|November 14, 2025
Summary
Fibrinogen exhibits distinct mechanical responses to cyclic stress due to its structural asymmetry. Simulations reveal viscoelastic behavior with implications for blood clot formation and ischemic stroke.
Area of Science:
- Biophysics
- Computational Biology
- Materials Science
Background:
- Fibrinogen is crucial for blood coagulation and implicated in ischemic stroke.
- This protein is routinely subjected to mechanical forces during physiological processes.
Purpose of the Study:
- To investigate the mechanical response of fibrinogen under cyclic high-strain loading.
- To understand the role of structural asymmetry and pulling direction on fibrinogen's behavior.
Main Methods:
- Atomistic molecular dynamics simulations of fibrinogen under three cycles of loading and unloading.
- Simulations captured forces applied to different fibrinogen nodules (γ1 and γ2) in opposite directions.
- Anisotropic normal mode analysis and Kelvin-Voigt modeling were used to analyze mechanical properties.
Main Results:
- Contrasting mechanical behaviors were observed between fibrinogen nodules: γ1 showed elasticity, while γ2 exhibited resistance and irreversible damage.
- Residual strain was retained after force relaxation, indicating partial irreversibility.
- Localized stiffness reductions and viscoelastic relaxation dynamics were quantified.
Conclusions:
- Fibrinogen's cyclic mechanical response is influenced by its intrinsic structural heterogeneity.
- The study demonstrates fibrinogen's viscoelastic properties under cyclic stress.
- Findings have significant implications for understanding clot formation and stroke pathogenesis.
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