Additive manufacturing of hierarchical injectable scaffolds for tissue engineering

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Additive Manufacturing

Background:

• Minimally invasive delivery requires injectable scaffolds that maintain structural integrity and cell viability.
• Current 3D bioprinting technologies often struggle to produce large-scale scaffolds suitable for injection.

Purpose of the Study:

• To develop a 3D printing technology for fabricating centimetre-scale, injectable, and biocompatible scaffolds.
• To demonstrate control over scaffold properties, such as pore size, for modulating biological responses in vivo.

Main Methods:

• Utilized a cryogenic 3D printing technique with carboxymethylcellulose-based cryogel inks.
• Optimized printing parameters, including substrate temperature, to control pore size and ink properties.
• Assessed scaffold injectability, biocompatibility, and inflammatory response in murine subcutaneous models.
• Evaluated in vitro cell viability and in vivo vascularization density.

Main Results:

• Fabricated highly porous, elastic, and compressible cryogel scaffolds capable of withstanding extreme compression ratios for injection.
• Demonstrated excellent cell viability protection during injection.
• Showcased long-term biocompatibility with minimal inflammation and encapsulation after three months post-implantation.
• Established a correlation between local pore size and controlled vascularization density in vivo.

Conclusions:

• The developed 3D printing technology enables the fabrication of large, injectable, and biocompatible scaffolds.
• Control over local pore size during printing allows for modulation of the in vivo biological response, specifically vascularization.
• This approach offers a promising platform for advanced tissue engineering and regenerative medicine applications requiring minimally invasive delivery.