Microfluidic Production of Ultrathin, Handleable Collagen Sheets Exhibiting Toe-heel Tensile Behavior

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Biophysics

Background:

• Cardiovascular tissues possess a unique non-linear, strain-dependent elastic modulus due to hierarchical collagen organization.
• Current engineered collagen materials lack the microscale hierarchical structure and mechanical properties of native tissues.
• This limits their application in 3D cell culture, tissue engineering, and biofabrication.

Purpose of the Study:

• To develop ultrathin, templated collagen sheets that replicate the non-linear tensile behavior and strength of native cardiovascular tissues.
• To engineer microscale hierarchical organization within collagen materials.

Main Methods:

• A microfluidic wet spinning process was used to create ultrathin collagen sheets (1.8 microns).
• Microscale oil droplets were incorporated and removed to create templated structures, enhancing fibril alignment dispersion.
• The mechanical properties, specifically Young's modulus and tensile behavior, were assessed.

Main Results:

• Templated collagen sheets showed a two-fold increase in fibril alignment dispersion compared to non-templated sheets.
• The Young's modulus of templated sheets increased 62-fold at 90% failure strain, mimicking native tissue behavior.
• The engineered sheets recapitulated the non-linear, strain-dependent mechanical properties of load-bearing tissues.

Conclusions:

• Ultrathin templated collagen sheets successfully replicate the hierarchical structure and non-linear mechanical properties of native cardiovascular ECM.
• These engineered collagen sheets offer a promising substrate for bottom-up fabrication of load-bearing biomaterials.
• Potential applications include in vitro tissue models and implantable biomedical devices.