Variability in individual native fibrin fiber mechanics

Area of Science:

• Biophysics
• Biochemistry
• Materials Science

Background:

• Fibrin fibers are crucial for blood clot structure and mechanical integrity.
• Previous studies show variability in fibrin fiber mechanics, but the underlying causes are not fully understood.

Purpose of the Study:

• To investigate the effect of fibrinogen concentration on fibrin fiber mechanical properties.
• To characterize modulus, strain hardening, extensibility, and failure force of fibrin fibers formed at different concentrations.

Main Methods:

• Lateral force atomic force microscopy (LF-AFM) was used to measure mechanical properties.
• Fibrin fibers were formed using varying fibrinogen concentrations (1 mg/mL and 2 mg/mL).
• Scanning Electron Microscopy (SEM) was employed to examine fiber formation differences.

Main Results:

• Fibers formed from 1 mg/mL and 2 mg/mL fibrinogen exhibited significantly different mechanical properties.
• Two distinct fiber behavior profiles were identified based on modulus, extensibility, strain hardening, and strength.
• Lower fibrinogen concentrations (1 mg/mL) resulted in highly extensible fibers with significant strain hardening, while higher concentrations (2 mg/mL) produced stiffer, stronger fibers with low extensibility.

Conclusions:

• Fibrinogen concentration is a key determinant of fibrin fiber mechanical properties.
• The observed range of mechanical behaviors likely occurs *in vivo* and may influence coagulative disorders.
• Understanding this variability is essential for comprehending blood coagulation pathophysiology.