2024 AIChE Annual Meeting

The Art of Guided 3D Vascular Channels Via Bioprinting

The formation of blood vessels are crucial for efficient wound healing as they supply the necessary nutrients and oxygen to the damaged area. At the heart of this process are two critical phenomena: vasculogenesis and angiogenesis. Vasculogenesis is the formation of new blood vessels from progenitor or stem cells, while angiogenesis is the growth of new blood vessels from pre-existing ones. In our previous study, a co-culture of fibroblasts and dental pulp stem cells (DPSCs) with collagen-fibrin ECM was verified as a pro-angiogenesis combination without additive growth factor. Through an integrated co-culture system into our engineered skin tissue, we produced pre-vascularized skin constructs that integrate and form anastomoses with host blood vessels in vivo.

This study aims to optimize the process of creating customized blood vessel patterns using 3D bioprinting. A key challenge in this process is ensuring the formation of a hollow structure with endothelial cells adhering to the walls of the channels. To address this, the thermal properties of gelatin and collagen were utilized to form a small hollow structure mimicking blood vessels. Gelatin was mixed with endothelial cell slurry to serve as a sacrificial material, after 3d printed, gelatin will be dispersed as collagen gelled at higher temperatures, allowing endothelial cells to bind to nearby collagen sites, facilitating vasculogenesis. Enhanced green fluorescent protein-labeled human umbilical vein endothelial cells (EGFP-HUVECs) were used to track the development of these vessels. By carefully controlling the temperature and combining collagen - fibrin as the ECM, the EGFP-HUVECs successfully adhered to the walls of the hollow channels, replicating the endothelial lining found in natural blood vessels. The angiogenesis was observed as early as day 3. By day 11, there is obvious interconnection among channels, suggesting anastomosis in the culture. The current data and results support the feasibility of regulating blood vessel patterns in vitro, which is crucial for accelerating the repair process at injury sites. These findings offer promising potential for future manufacturing efforts to integrate vasculature into bioengineered skin grafts.