Multifilament Collagen Fiber Bundles with Tendon-like Structure and Mechanical Performance.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Polymer Chemistry

Background:

• Collagen is the primary structural protein in connective tissues like tendons.
• Replicating the hierarchical structure and mechanical properties of native tendons remains a significant challenge in biomaterials research.

Purpose of the Study:

• To develop a fabrication method for collagen multifilament bundles that recapitulates native tendon structure across multiple length scales.
• To enhance the mechanical properties of these collagen bundles using ultraviolet C (UVC) crosslinking.

Main Methods:

• Preparation of collagen multifilament bundles via multipin contact drawing of collagen and poly(ethylene oxide) (PEO) solution.
• Hydration of bundles in graded PEO and phosphate-buffered saline (PBS) to promote collagen fibril assembly.
• Multiscale structural characterization and sequence analysis to understand molecular packing and crosslinking sites.
• UVC radiation to crosslink phenylalanine residues and enhance mechanical strength.

Main Results:

• Fabricated multifilament bundles exhibit collagen molecules organized into fibrils with microfibrils staggered at a specific D-band spacing (11 nm periodicity).
• UVC crosslinking significantly increased the ultimate tensile strength (UTS) and Young's modulus of the collagen bundles.
• Achieved mechanical properties comparable to native tendons without discernible damage to collagen molecules.

Conclusions:

• The developed fabrication method successfully mimics tendon structure and enhances mechanical properties through UVC crosslinking.
• This approach offers a tunable and additive-free method for creating high-performance collagen biomaterials.
• The process demonstrates potential for engineering functional tissue replacements and advanced biomaterials.