Indirect Tissue Scaffold Fabrication via Additive Manufacturing and Biomimetic Mineralization

Unlike traditional stochastic scaffold fabrication techniques, additive manufacturing (AM) can be used to create tissue-specific three-dimensional scaffolds with controlled porosity and pore geometry (meso-structure). However, due to the relatively few biocompatible materials available for processing in AM machines, direct fabrication of tissue scaffolds is limited. To alleviate material limitations and improve feature resolution, a new indirect scaffold fabrication method is developed. A four step fabrication process is explored: Fused Deposition Modeling (FDM) is used to fabricate scaffold patterns of varied pore size and geometry. Next, scaffold patterns are surface treated, and then mineralized via simulated body fluid (SBF); forming a bone-like ceramic throughout the scaffold pattern. Finally, mineralized patterns are heat treated to pyrolyze the pattern and sinter the minerals. Two scaffold meso-structures are tested: "tube" and "backfill." Two pattern materials are tested [acrylonitrile butadiene styrene (ABS) and investment cast wax (ICW)] to determine which material is the most appropriate for mineralization and sintering. Mineralization is improved through plasma surface treatment and dynamic flow conditions. Appropriate burnout and sintering temperatures to remove pattern material are determined experimentally. While the "tube scaffolds" were found to fail structurally, "backfill scaffolds" were successfully created using the new fabrication process. The "backfill scaffold" meso-structure had wall thicknesses of 470 – 530 µm and internal channel diameters of 280 – 340 µm, which is in the range of appropriate pore size for bone tissue engineering. "Backfill scaffolds" alleviated material limitations, and had improved feature resolution compared to current indirect scaffold fabrication processes.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2010

Author dc:creator

• Bernardo, Jesse Raymond

Chair dc:contributor.committeechair

• Williams, Christopher B.

Committee members dc:contributor.committeemember

• Goldstein, Aaron S.
• Bohn, Jan Helge
• Morgan, Abby W.

• Fused Deposition Modeling
• Mineralization
• Additive manufacturing
• Tissue Scaffold

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-12192010-114500

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/36312