Discipline: Chemistry and Chemical Sciences
Subcategory: Materials Science
Myischionna Hunter - Alabama State University
Co-Author(s): Elijah Nyairo and Derrick Dean, Alabama State University, Montgomery, AL
The fields of 3-D Printing and tissue engineering have seen explosive growth over the last decade. This growth is driven in part by the need to replace or repair damaged tissues and organs. A significant amount of effort has been aimed at developing scaffolds that can mimic the characteristics of the extracellular matrix, ECM. Some of the key requirements of an effective scaffold include: (1) biocompatibility with host tissue; (2) high degree of interconnected porosity for ingrowth and movement of cells, and flow of nutrients and waste; (3) 3-dimensionality; (4) surface chemistry that promotes cell adhesion, proliferation and differentiation; (5) mechanical properties that match those of the host tissue. A number of approaches for generating porous, 3-dimensional biodegradable polymeric scaffolds have been reported, including solvent and particulate leaching, phase-separation, freeze drying, and self-assembly. While all of these approaches have advantages and disadvantages, some of the key shortcomings include the lack of precise control of pore geometry, size, distribution and interconnectivity. These shortcomings can be addressed by fabricating scaffolds of varying biocompatible polymers using by 3-D printing. In this project, we are interested in designing digital models for the fabrication of polymeric tissue scaffolds by 3-D printing. We have developed a number of models that allow us to systematically control scaffold parameters such as pore size, geometry and overall porosity. Using a dynamic mechanical analyzer, we characterized the scaffolds by their stress, strain, modulus, and other pertinent properties. As we hypothesized, the unidirectional sample had a very low modulus whereas the multidirectional design had the highest modulus and porosity. The multidirectional results showed that the scaffold was comparable to cancellous bone and some tissues. Further studies would allow for optimization of these designs, exploration of other polymers independently and within hybrid scaffolds, and investigation into cell-scaffold interaction studies.
References: M. Li, X. Chen, A brief review of dispensing-based rapid prototyping techniques in tissue scaffold fabrication: role of modeling on scaffold properties prediction, Biofabrication 1 (2009).
J.M. Sobral, S.G. Caridade, R.A. Sousa, J.F. Mano, R.L. Reis, Three-dimensional plotted scaffolds with controlled pore size gradients: effect of scaffold geometry on mechanical performance and cell seeding efficiency, Acta Biomater. 7 (2011) 1009-1018.
Sheshadri, Priyanka, and Rohan A. Shirwaiker. ‘Characterization of Material- Process- Structure Interactions in the 3D Bioplotting of Polycaprolactone.’ 3D Printing and Additive Manufacturing 2.1 (2015): 20-31.
Funder Acknowledgement(s): This work was supported by NSF/RUI award 1510479 to Derrick Dean. This work was supported by NSF-REU (DBI-1358923) to Komal Vig (PI). This work was supported by NSFCREST (HRD-1241701) to Shree S. Singh (PI).
Faculty Advisor: Derrick Dean, email@example.com
Role: I designed the scaffolds using various CAD softwares, I 3-D printed the scaffolds, I aided in the mechanical testing trials, and I analyzed the results to draw conclusions.