3D-printed biomaterials with regional auxetic properties

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Cell differentiation is critical for tissue regeneration, requiring precise control over the cellular microenvironment.
• Existing methods for inducing cell differentiation often lack the mechanical control needed for complex tissue applications like muscle and tendon repair.

Purpose of the Study:

• To develop a 3D-printed scaffold with non-positive Poisson's Ratio (NPPR) properties for stretch-mediated cell differentiation.
• To investigate the potential of NPPR scaffolds in supporting cell growth and enabling tunable mechanical properties for tissue engineering.

Main Methods:

• Fabrication of multi-layered, cell-laden NPPR scaffolds using dynamic optical projection stereolithography (DOPsL).
• Integration of NPPR scaffolds within elastic hydrogels to create hybrid structures with tunable Poisson's Ratio.
• Characterization of scaffold properties for cell interaction and potential 'auxetic' behavior at the single-cell scale.

Main Results:

• Successfully fabricated 3D-printed NPPR scaffolds capable of supporting aggregate cell growth.
• Demonstrated locally-tunable force-displacement properties at relevant length scales for tissue interaction.
• Proposed a hybrid structure that couples NPPR behavior with a positive Poisson's Ratio (PPR) material to induce auxetic effects.

Conclusions:

• The developed NPPR scaffolds offer a promising platform for stretch-mediated cell differentiation in tissue engineering.
• The ability to tune mechanical properties and induce auxetic behavior at the cellular level is advantageous for muscle and tendon regeneration.
• This approach holds potential for advancing therapies in the tendon-to-muscle tissue transition zone.