Capturing sclera anisotropy using direct collagen fiber models: linking microstructure to macroscopic mechanical...

Area of Science:

• Biomechanics
• Materials Science
• Tissue Engineering

Background:

• Collagen fibers are crucial for soft tissue mechanical properties, particularly in the sclera.
• Traditional models often use statistical fiber representations, potentially overlooking key structural contributions to tissue behavior.

Purpose of the Study:

• To refine a direct fiber modeling approach for explicit representation of scleral fiber bundles.
• To capture specimen-specific 3D fiber architecture and anisotropic mechanics of ovine sclera.

Main Methods:

• Extracted fiber architecture from ovine sclera using polarized light microscopy.
• Reconstructed 3D fiber orientations and compared them with histological data (adjusted R² > 0.89).
• Determined material parameters via inverse fitting to equi-biaxial tests and validated against non-equi-biaxial conditions.

Main Results:

• Reconstructed fiber orientations showed strong agreement with histological findings.
• Parameters derived from equi-biaxial tests accurately predicted mechanical responses under various non-equi-biaxial loading conditions.
• The direct fiber model inherently captured tissue anisotropy, unlike conventional models.

Conclusions:

• Direct fiber modeling effectively links scleral fibrous structure to macroscopic mechanical behavior.
• This approach offers a promising alternative to conventional models for understanding anisotropic soft tissue mechanics.
• The study highlights the importance of explicit fiber representation for accurate biomechanical predictions.