Poster BB16 - Fabricating Biomimetic Vascular Networks in Engineered Tissue through 3D Freeform Ice Printing

Introduction: Tissue engineering aims to narrow the considerable gap between organ availability and the urgent demand for transplants. Despite considerable advancements, a significant challenge remains: the integration of functional, biomimetic vascular networks within engineered solid organs and dense tissues, spanning from capillaries to arteries. In response to these challenges, we introduce a novel approach—using 3D freeform ice printing as sacrificial vasculature templates.

Materials and

Methods: Our technique involves depositing water droplets on a chilled substrate, enabling the creation of ice geometries with smoothly varying cross-sections and complex structures. These ice templates mimic natural vasculature, boasting complex shapes, circular cross-sections, a wide range of diameters, and seamless branching. By embedding these ice templates in an uncrosslinked GFP-expressing Fibroblast Cell-laden gelatin methacrylate (GelMA) prepolymer solution, and upon UV exposure, the solution crosslinks, and the ice subsequently melts, leaving behind desired well-defined vascular conduits within cell embedded GelMA scaffolds. The GelMA proves advantageous in this context due to its capability for rapid crosslinking at low temperatures. A dense suspension of RFP-expressing human umbilical vein endothelial cells (HUVECs) was seeded into these conduits engineered in GelMA scaffolds, and subsequently cultured for 14 days.

Results, Conclusions, and Discussions: Our results demonstrate the formation of vascular conduits within GelMA hydrogels using our approach. The proliferation of Fibroblast cells in GelMA scaffolds indicates the potential ability to create engineered tissue. The HUVECs seeded in the engineered tissue GelMA scaffolds exhibited lumen formation after 14 days of culture, showcasing the potential of cellularizing vascularized tissue engineering constructs fabricated using the freeform ice printing process.

In this study, we demonstrated the potential of our novel freeform 3D ice printing technique for fabricating sacrificial 3D vasculature templates. These templates facilitated the creation of biomimetic vascular conduits within GelMA hydrogel scaffolds at physiologically relevant size scales. Cell seeding tests underscored the feasibility of seeding endothelial cells within the channels. Leveraging the unique properties of water, this innovative technique shows significant promise, particularly in terms of biocompatibility, for advancing the development of complex, biomimetic vascular networks in tissue engineering.

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