Three-Dimensional Rapid Prototyping of Vascular Substitutes for Medical Applications
Connor Dodge, Alex Bischoff, Jason Griggs, Kyle Larsen, Sarah Livingston, Sterling Rosqvist, Tomonori Baba, Tyler Hendricks, Alonzo D. Cook PhD.
Brigham Young University, Provo, Utah, USA
Autologous transplant of a patient’s living veins is the most common clinical practice for atherosclerotic disease of the peripheral arteries. Often, it is non-ideal to transect a sick patient’s veins to substitute for an artery. The search for an ideal arterial substitute has taken exciting new turns. The newest research focuses on recreating and then implanting arteries from a patient’s own cells in vitro, with no immunological effects and having every functional property of a living artery. Our blood vessel research team has entered the tissue engineering field in its most exciting effort: the scalable rendering of cell-seeded vascular constructs with rapid prototyping machines or 3D printers. Gabor Forgacs Ph.D. and other researchers have pioneered the organ printing field. To date, these scientists have managed to build 3-dimensional scaffolds of organs and vasculature while simultaneously seeding living cells using the same machines.
We have built and are modifying a 3D printer that will allow us to test several different avenues of 3D organ genesis. We are currently testing the viability of lyophilized alginate gel, fibronectin coated alginate gel, and methacrylated alginate gel as bio-compatible organ scaffolds. Using these three materials as scaffolds, we hope to learn more about the ideal conditions for cell growth and replication on a polymer scaffold.
We plan to construct blood vessels by 3D printing a cylindrical shape, then preparing it in the correct manner; by either lyophilization, coating with fibronectin, or methacrylation, and attaching the structure to a pump and circulating live endothelial cells through the lumen of the polymer scaffold. We currently perform tests with MS1 endothelial cells, and plan to include smooth muscle cells in our upcoming tests to observe the interaction between endothelial and smooth muscle cells on a polymer scaffold. We expect that with the right pump speed and environment, endothelial cells will attach to the lumen of the polymer scaffold and align themselves as they replicate to cover the inside surface, creating a non-thrombogenic section of blood vessel.
To test functionality we will compare tensile strength with Young’s modulus models, test for blood contacting with thrombogenicity measurements in partnership with Thrombodyne Inc., ensure synchronization of smooth muscle contractions, and eventually perform autologous animal tests to identify signs of immunogenic rejection.
Funding was provided by Brigham Young University and the Office of Research and Creative Activities (ORCA).
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