3D Printing of Porous Scaffolds for Medical Applications

Custom engineered scaffolds that mimic the physiology of native tissue is an emerging need for successful regenerative medicine. One of the key challenges in current manufacturing methods is the lack of controlled porosity throughout the scaffold structure. In this research, our group explores the fabrication of tissue engineering scaffolds using 3D printing technology. The fused deposition modeling method was utilized to fabricate scaffolds with different unit-cell designs and in-fill densities. Specimens were fabricated in Acrylonitrile-Butadiene-Styrene (ABS) material for different pattern designs which include linear, hexagonal, diamond and Moroccan star. The experimental phase of this research revealed the influence unit-cell design, in-fill density and pattern orientation on the porosity of the specimens. Computational modeling using finite element analysis was conducted to study the relationship between structure, porosity and mechanical strength of the scaffolds. A comparative analysis was performed for ASTM standard specimens for tensile and compression tests for von Mises stress and displacement values. The results indicated that diamond unit-cell pattern had the highest stress and displacement. In contrast, the hexagonal honey-comb pattern had the best mechanical strength, especially for higher porosities. Specimens loaded in the compressive mode had 50% lower stress values as compared to tensile tests. Thus, by manipulating the unit-cell type, in-fill density and pattern orientation one can fabricate a scaffold structure that balances cellular function with the load-bearing requirement for a specific application. This research lays a foundation for evaluating additive manufacturing technologies for biomedical implants by manipulating both process parameters and material properties.