Combining tensile testing and structural analysis at the single collagen fibril level

Area of Science:

• Biomaterials Science
• Biophysics
• Connective Tissue Research

Background:

• Studying the structure-function relationship in connective tissues like skin, tendon, and ligament is crucial.
• The hierarchical nature of these tissues presents significant challenges in data interpretation across multiple length scales.
• Collagen fibrils are the fundamental tensile elements in load-bearing biological tissues.

Purpose of the Study:

• To create a dataset linking mechanical failure to molecular changes at the single collagen fibril level.
• To provide a resource for researchers modeling or designing functional protein materials.
• To investigate the behavior of collagen fibrils under tensile stress.

Main Methods:

• Extraction and isolation of single collagen fibrils from bovine tendons.
• Tensile testing to failure using an atomic force microscope (AFM) in a bowstring geometry.
• Post-failure imaging and analysis using AFM, second harmonic generation microscopy, and fluorescence microscopy with a peptide probe.

Main Results:

• Acquisition of a dataset correlating stress-strain curves with post-failure molecular alterations in collagen fibrils.
• Morphological characterization of broken fibrils via AFM.
• Assessment of molecular packing changes using second harmonic generation microscopy.
• Identification of denatured collagen regions using fluorescence microscopy.

Conclusions:

• The generated dataset offers a comprehensive link between mechanical stress, fibril failure, and molecular-level changes.
• This data is highly valuable for advancing computational models of protein materials and biomechanics.
• The study provides a foundation for understanding and engineering collagen-based biomaterials.