Acellular and cellular high-density, collagen-fibril constructs with suprafibrillar organization

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Biophysics

Background:

• Collagen is crucial for tissue engineering due to its natural abundance and signaling roles.
• Existing collagen materials (atelocollagen, telocollagen) lack the density, organization, mechanical strength, and stability of native tissues.
• There is a need for advanced collagen-based biomaterials that mimic native tissue properties for effective tissue regeneration.

Purpose of the Study:

• To develop a method for creating highly organized and mechanically robust collagen matrices from collagen oligomers.
• To investigate the effects of controlled densification on the mechanical properties and degradability of collagen constructs.
• To assess the suitability of the developed method for creating cellularized tissue constructs with high cell viability.

Main Methods:

• Creation of interconnected, low-density D-banded collagen fibril matrices from collagen oligomers.
• Application of confined compression to controllably reduce interstitial fluid and increase collagen density.
• Characterization of mechanical properties (ultimate stress, Young's modulus, compressive modulus) and collagenase resistance.
• Evaluation of cell viability in cellularized constructs post-densification and during culture.

Main Results:

• Densification increased collagen concentrations from 3.5 mg/mL to 12.25 mg/mL and 24.5 mg/mL.
• Mechanical properties significantly improved, with Young's modulus increasing up to 1.26 MPa.
• Densified constructs showed enhanced resistance to collagenase degradation.
• Cell viability remained high (≥97%) throughout the process and subsequent culture.

Conclusions:

• The integration of collagen oligomer assembly and confined compression enables the creation of high-density collagen-fibril materials.
• This method significantly enhances mechanical integrity and proteolytic resistance of collagen scaffolds.
• The process is scalable and supports the rational design of advanced collagen-based biomaterials for diverse tissue engineering applications.