Nanomechanical 3D Depth Profiling of Collagen Fibrils in Native Tendon

Area of Science:

• Biophysics
• Materials Science
• Tissue Engineering

Background:

• Connective tissue biomechanics, particularly collagen fibrils, involves complex nanoscale processes.
• Understanding molecular-level mechanics is essential for comprehending tissue function.

Purpose of the Study:

• To investigate the 3D nanomechanical properties of collagen fibrils and their matrix in native, hydrated tendons.
• To elucidate the role of interfibrillar bonds and matrix properties in tendon biomechanics.

Main Methods:

• Utilized atomic force microscopy (AFM) for high-resolution imaging of unfixed, hydrated Achilles tendon.
• Collected force-distance (FD) and amplitude-phase-distance (APD) data to map nanomechanical properties.
• Constructed 3D depth profiles with 0.1 nm depth and 10 nm lateral resolution.

Main Results:

• Observed diverse nanomechanical properties (adhesive, viscoelastic) among individual collagen fibrils.
• Identified variations in mechanical responses at contact points between adjacent collagen fibrils.
• Revealed the nanomechanical morphology of hydrated collagen fibrils in native tendon.

Conclusions:

• Nanoscale variations in collagen fibril mechanics significantly impact connective tissue biomechanics.
• Interfibrillar bonds and matrix properties play a critical role in tendon mechanical response.
• AFM provides unprecedented insight into the native, hydrated state of connective tissues.