A versatile method for combining different biopolymers in a core/shell fashion by 3D plotting to achieve mechanically...

Area of Science:

• Biomaterials Engineering
• Tissue Engineering
• Bioprinting Technologies

Background:

• Three-dimensional (3D) extrusion of multiple biomaterials in a core/shell (c/s) configuration is an emerging technique for fabricating advanced constructs.
• Soft biopolymer hydrogels often lack the mechanical integrity for direct 3D plotting of open-porous structures without external support.

Purpose of the Study:

• To develop and characterize mechanically stable 3D scaffolds using a c/s extrusion approach with alginate shells and various soft hydrogel cores.
• To evaluate the potential of these scaffolds for controlled growth factor delivery and cell encapsulation in bioprinting applications.

Main Methods:

• Fabrication of c/s 3D scaffolds by extruding high-concentration alginate (shell) and low-concentration biopolymer hydrogels (core: alginate, chitosan, gellan gum, gelatin, collagen).
• Characterization of scaffold morphology, mechanical properties, and swelling behavior.
• Loading of scaffolds with growth factors (VEGF, BMP-2) and assessment of release kinetics.
• Integration of live human endothelial cells into the core material.

Main Results:

• The combination of alginate shells and soft hydrogel cores resulted in mechanically stable and robust 3D scaffolds.
• Scaffolds supported the loading and controlled release of growth factors, influenced by core composition and shell thickness.
• The fabrication process and CaCl2 crosslinking did not denature proteins within the hydrogels.
• Dual growth factor release (VEGF and BMP-2) was achieved by loading different factors into the core and shell.
• Live endothelial cells remained viable and were successfully integrated into the core material.

Conclusions:

• The developed c/s 3D bioprinting strategy enables the creation of robust scaffolds from otherwise mechanically weak hydrogels.
• This method offers tunable control over growth factor release profiles and is suitable for incorporating living cells, paving the way for advanced bioprinting applications.