Expanding Embedded 3D Bioprinting Capability for Engineering Complex Organs with Freeform Vascular Networks

Area of Science:

• Biofabrication
• Tissue Engineering
• Regenerative Medicine

Background:

• Replicating complex organ geometry and internal structures, like blood vessels, remains a significant challenge in biofabrication.
• Existing 3D printing strategies struggle to simultaneously address external organ shape and internal vascularization.

Purpose of the Study:

• To develop a generalizable bioprinting strategy to overcome limitations in fabricating complex organ constructs.
• To demonstrate a novel bioink and printing technique for creating functional tissues with integrated vascular networks.

Main Methods:

• Development of a microgel-based biphasic (MB) bioink with shear-thinning and self-healing properties.
• Implementation of the Sequential Printing In Reversible Ink Template (SPIRIT) strategy using the MB bioink.
• 3D printing of cardiac tissues, organoids, and a ventricle model with a perfusable vascular network using encapsulated human-induced pluripotent stem cells.

Main Results:

• The MB bioink functions effectively as both a bioink and a suspension medium for embedded 3D printing.
• SPIRIT strategy successfully enabled the fabrication of a ventricle model with a perfusable vascular network, a feat not achievable with current methods.
• 3D printing with MB bioink promoted extensive stem cell proliferation and cardiac differentiation, leading to functional cardiac tissues and organoids.

Conclusions:

• The SPIRIT technique offers a significant advancement in bioprinting complex organ geometries and internal structures.
• This approach accelerates the biofabrication of tissue and organ constructs, paving the way for enhanced therapeutic applications.