Loading causes molecular damage in fibrin fibers.

Area of Science:

• Biophysics
• Materials Science
• Biochemistry

Background:

• Blood clots, essential for wound healing, can cause pathologies like ischemic stroke.
• Fibrin fibers provide mechanical strength to clots but their dynamic mechanical properties are poorly understood.
• Cyclic loading, common in vivo, can reveal distinct mechanical responses in biological materials.

Purpose of the Study:

• To investigate the mechanical properties of single fibrin fibers under dynamic loading conditions.
• To understand the molecular mechanisms of damage and structural changes in fibrin fibers during cyclic loading.
• To correlate findings with clot behavior in wound healing and pathologies such as stroke and embolism.

Main Methods:

• Lateral Force Microscopy (LFM) to probe single fiber mechanics.
• Computational modeling to corroborate experimental findings.
• Broadband Raman scattering spectroscopy and molecular dynamics simulations to analyze molecular changes.

Main Results:

• Fibrin fibers exhibit viscoelasticity and undergo irreversible molecular damage under cyclic loading.
• Cross-linking increases fibrin rigidity and causes permanent damage at larger strains.
• Spectroscopy and simulations identified partial recovery of protein structure and revealed molecular wear mechanisms.

Conclusions:

• Fibrin fibers experience molecular wear and structural changes under dynamic loading, impacting clot function.
• Understanding fibrin's mechanical behavior under load is crucial for comprehending wound healing and thrombotic diseases.
• This study offers a deeper insight into fibrin's role in pathologies like stroke and embolism.