Loading causes molecular damage in fibrin fibers

Area of Science:

• Biophysics
• Materials Science
• Biochemistry

Background:

• Blood clotting involves fibrin, the main protein providing mechanical strength to clots.
• Fibrin fibers display extensibility and elastic properties under static loads, but in vivo dynamics differ.
• The mechanical response of biological materials can change under cyclic loading.

Purpose of the Study:

• To investigate the mechanical behavior of fibrin fibers under cyclic loading.
• To identify the molecular mechanisms behind fibrin fiber damage and recovery.
• To understand fibrin's role in physiological and pathological processes.

Main Methods:

• Lateral force microscopy to observe fibrin fiber behavior.
• Computational modeling using a hyperelastic model for fibrin extension.
• Molecular spectroscopy (broadband coherent anti-Stokes Raman scattering) and molecular dynamics simulations.

Main Results:

• Fibrin fibers demonstrate viscoelastic behavior and irreversible damage under cyclic loading.
• Cross-linking increases rigidity but also leads to permanent damage at larger strains.
• Spectroscopy and simulations identified protein unfolding and structural changes as sources of damage, with partial recovery observed.

Conclusions:

• Fibrin fibers exhibit complex viscoelasticity and susceptibility to damage under dynamic forces.
• Understanding fibrin's mechanical response is vital for comprehending its role in wound healing and pathologies.
• This research provides insights into fibrin's structural dynamics and its implications in thrombosis and embolism.