Multiscale Porosity in Compressible Cryogenically 3D Printed Gels for Bone Tissue Engineering

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• 3D Printing Technology

Background:

• 3D printing of complex gel constructs for medical applications remains challenging.
• Existing methods struggle to achieve controlled hierarchical structures in printed gels.

Purpose of the Study:

• To develop a novel method for 3D printing complex composite gel scaffolds with controlled hierarchical structures.
• To fabricate bioactive scaffolds using gelatin/carboxymethylchitin/hydroxyapatite for potential bone regeneration applications.

Main Methods:

• Utilized a cryogenic 3D printing technique in a local cold atmosphere for instant gel freezing.
• Incorporated lyophilization for microporosity and cross-linking to control scaffold properties.
• Investigated the effect of cross-linker and polymer concentration on pore size and distribution.

Main Results:

• Successfully fabricated complex gel constructs with controlled outer shape, macroporosity, and microporosity (up to 90%).
• Achieved a six-fold increase in surface open pores (<20 μm) by adjusting cross-linker concentration.
• Demonstrated enhanced swelling, human umbilical cord mesenchymal stem cell and Saos-2 cell attachment (2×), proliferation (2.4×), and mineralization (3×).

Conclusions:

• Cryogenic 3D printing combined with lyophilization offers a viable method for producing bioactive gel scaffolds with multiscale porosity.
• These scaffolds exhibit excellent biocompatibility and osteogenic potential, suitable for patient-specific bone defect repair.
• The developed technique allows for precise control over scaffold architecture and properties for regenerative medicine applications.