Multi-casting approach for vascular networks in cellularized hydrogels.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Vascularization is critical for engineered tissues but remains a significant hurdle.
• Lack of perfusable channels leads to cell death and limits construct size.
• Fabricating functional tissues and organs requires overcoming vascularization challenges.

Purpose of the Study:

• To develop a novel method for creating hierarchical, 3D perfusable vasculature in large, cellularized hydrogels.
• To enable the fabrication of complex, customizable vascular architectures for tissue engineering.
• To improve cell viability and distribution within engineered tissue constructs.

Main Methods:

• Utilized a 3D printing technique to create thermoplastic templates for channel formation.
• Converted thermoplastic templates into gelatin network scaffolds via an alginate hydrogel intermediate.
• Fabricated cellularized fibrin hydrogels around the removable templates, creating perfusable channels.

Main Results:

• Successfully created hierarchical, bifurcating channels ranging from 1 mm to 200-250 µm.
• Achieved uniform, high cell density in the bulk hydrogel (collagen and fibrin).
• Demonstrated good cell seeding, tight endothelial cell junctions, and high cell viability and spreading.

Conclusions:

• The novel method enables the creation of complex, customizable, and perfusable vascular networks in large tissue constructs.
• This approach addresses a key limitation in tissue engineering, paving the way for larger and more functional engineered tissues.
• The technique supports high cell viability and distribution, crucial for developing viable engineered tissues and organs.