3D Printing of Biodegradable Scaffolds for Tissue Engineering Applications

With the recent improvements in three dimensional (3D) printing technologies, the potential for tissue engineering and regenerative medicine have significantly improved. One key idea in tissue engineering is to specifically design scaffolds to aid in the healing process by being incorporated into the body’s own tissue. The overall goal of this project is to investigate 3D printable scaffold design to access suitability for tissue replacement. This was accomplished by analyzing the effect of the material used to create the scaffolds, pore size, and pore shape on mechanical stiffness and cell culturability. Based on published literature, it was determined that, depending upon the desired tissue type, the best pore shapes are circles, squares, and hexagons. This study focused on designing numerous scaffolds by varying the parameters listed above, and then printing 3D biodegradable (PLA & TPU) scaffolds to be cultured, mechanically tested and evaluated. The scaffolds were cultured with endothelial cell lines to ensure cell survivability on the 3D printed material. After cell culturing protocol, cell attachment and viability were assessed and cell density recorded. The mechanical tests were performed using a standard tension test machine in order to gather stiffness and strength data. By analyzing our results, we will be able to make recommendations regarding which pore shape, size, and porosity will yield the most anatomically compliant results for the desired tissue

3D Printed PLA Scaffolds to Promote Healing of Large Bone Defects

One challenge modern medicine faces is the ability to repair large bone defects and stimulate healing. Small defects typically heal naturally, but large bone defects do not and current solutions are to replace the missing tissue with biologically inert materials such as titanium. This limits the amount of bone healing as the defect is not repaired but rather replaced. The focus of our research is to develop a method of using 3D printing to create biodegradable scaffolds which promote bone in-growth and replacement. To accomplish this we used poly lactic acid (PLA) filament and a desktop 3D printer. To promote bone healing and provide mechanical support our team investigated different design methodologies to provide a scaffold of customizable stiffness while allowing cell attachment and in-growth. Our team used CAD modeling to create unique architecture design systems which we analyzed for stiffness using Finite Element Analysis (FEA). We developed a unit cell method of scaffold construction that allowed for customized stiffness of irregular shapes. We 3D printed our designs using a desktop 3D printer and verified our stiffness through mechanical tension and compression testing. We investigated cell viability of the scaffolds by immersing test specimens in culturing media and fibroblast cells. Fibroblast cells are from the same lineage as osteoblast cells but are much faster growing, allowing for more efficient testing. Specimens were left in the media for one week then a total cell count was performed. Scaffold designs were then evaluated based on stiffness and cell viability. We have produced several different viable models with appropriate stiffness for human trabecular bone and good cellular adhesion