(I-339) Screening of Complex Architectures within 3D Bioprinted Hydrogels to Increase Rapid Vascularization

Introduction:: Introduction: Transplantation of engineered tissues and cells requires functional vascular networks to be present in close proximity to the transplanted tissue. Vascularization is a critical feature for transplanted cells to receive oxygen and nutrients and have metabolic wastes removed [1]. In the body vascular networks formed by blood vessels are organized into different patterns and blood vessel diameters depending on the area of the body. 3D bioprinting and stereolithography (SLA) are techniques that allow for 3D printing of biocompatible materials by creating photomasks of previously computer-aided design (CAD) files, by using digital light. Gelatin Methacrylate (GelMA) hydrogels with open architectures have previously been synthesized and 3D printed using a stereolithography approach to study vascularization in C57BL/6 mice models. Open architectures can be designed and modified by using Blender software. Different parameters such as channel length, diameter, volume, or complexity can help guide vascularization when implanting in vivo. In addition, pro-angiogenic agents could be perfused and combined with these complex architectures to promote rapid vascularization. Our goal is to screen the potential of complex architectures with GelMA 3D bioprinted hydrogels to guide blood vessel infiltration and angiogenesis for future fabrication of cell carrier platforms that can be used for cell and tissue transplantation.


Materials and Methods:: Materials and Methods: Blender software was used to design hydrogels containing hollow channels with different diameters, lengths, or architectures. GelMA pre-hydrogel solution was prepared with 10wt% GelMA, 3.25wt% 3.4 kDa polyethylene glycol diacrylate (PEGDA), 17 mM lithium phenyl-2,4,6-trimethyl benzoylphosphinate (LAP), 2.225 mM tartrazine, and 10wt% glycerol. Printing was performed on a Lumen stereolithography printer with a 6-second exposure time with 405 nm light. 3D printed hydrogels were implanted into the fat pads of 6–10-week-old immunocompetent C57BL/6 mice. Mice were intravenously injected with fluorescent dextran and explanted after 2, 4, and 8 weeks. Samples were evaluated with confocal microscopy and quantified using MATLAB software.


Results, Conclusions, and Discussions:: Results and Discussion: A cell carrier platform that could improve rapid vascularization is a critical need for cell transplantation. Here, we were able to develop and implant 3D bioprinted GelMA/PEGDA hydrogels containing channels with a variety of diameters, lengths, or architectures in C57BL/6 mice to help guide rapid vascularization. Hydrogels containing complex architectures were successfully implanted in between the fat pads in the intraperitoneal space of C57BL/6 mice for 8 weeks (Fig 1a). After retrieval, Capillary 3 architecture showed a higher presence of angiogenic factors within the open channels based on mean fluorescence intensity (Fig 1b,1c). Conclusion: Promising results on rapid vascularization of a 3D bioprinted hydrogel cell carrier platform for cell or tissue transplantation were gathered. Combination of leading architectures within 3D printed hydrogels with pro-angiogenic agents at different volumes and concentrations will be explored to further improve rapid vascularization.


Acknowledgements (Optional): : Martha Fowler, Shalini Pandey, Patrick Bednarz, Joe Swain, Dr. Jeffrey Hartgerink and Dr. Omid Veiseh. Rice University. JDRF.

References (Optional): : 1. Parkhideh, S., Calderon, G. A., Janson, K. D., Mukherjee, S., Mai, A. K., Doerfert, M. D., Yao, Z., Sazer, D. W., & Veiseh, O. (2023). Perfusable cell-laden matrices to guide patterning of Vascularization in vivo. Biomaterials Science, 11(2), 461–471. https://doi.org/10.1039/d2bm01200f