iPSC-Derived Vascular Cell Spheroids as Building Blocks for Scaffold-Free Biofabrication

Area of Science:

• Stem Cell Biology
• Tissue Engineering
• Regenerative Medicine
• Vascular Biology

Background:

• Established protocols yield human induced pluripotent stem cells (iPSC)-derived endothelial colony forming cells (ECFC) and smooth-muscle forming cells (SMFC).
• The potential of these cells for constructing 3D vascular tissues is largely unexplored.

Purpose of the Study:

• To evaluate the suitability of iPSC-derived ECFC and SMFC for spheroid formation and assembly into larger 3D cell constructs.
• To investigate the dynamic properties and fusion capabilities of these spheroids for scaffold-free biofabrication.

Main Methods:

• iPSC-derived ECFC and SMFC were labeled with fluorescent markers (tdTomato and eGFP, respectively).
• Spheroids were formed in ultra-low adhesive wells and analyzed using time-lapse and confocal microscopy.
• Spheroid fusion and assembly into 3D structures were assessed using in-well methods and the Regenova 3D bioprinter (Kenzan method).

Main Results:

• Both ECFC and SMFC formed stable spheroids within 24 hours, exhibiting distinct compaction dynamics.
• Mixed spheroids showed dynamic cell redistribution, with ECFC forming a pre-vascular core.
• SMFC-containing spheroids demonstrated robustness for assembling into tubular structures with layered cell distribution and extracellular matrix deposition.

Conclusions:

• iPSC-derived vascular cell spheroids are a viable cellular material for scaffold-free biofabrication.
• These spheroids demonstrate potential for creating functional 3D vascular constructs.
• The Kenzan method combined with SMFC-containing spheroids facilitates the assembly of robust tubular structures.