Development of controlled porosity polymer-ceramic composite scaffolds via fused deposition modeling

This research is focused on development and fabrication of controlled porosity polymer-ceramic composite scaffolds, with 3-D interconnectivity designed to promote richer supply of blood, oxygen and nutrients for healthy in-growth of bone cells. Particulate-reinforced polymer-ceramic composites were developed by high shear mixing of polypropylene (PP) polymer and tricalcium phosphate (TCP) ceramic. Processing aids were used to improve plasticity and processibility to the composites. Controlled porosity scaffolds were fabricated via the fused deposition process, one of the commercially available rapid prototyping (RP) techniques. These porous scaffolds were characterized for their use as bone grafts in terms of physical, mechanical and biological properties. Hg-porosimetry was performed to determine pore size and their distribution. Scaffolds with different complex internal architectures were also fabricated using this composite material. Tensile properties of neat PP (as received), PP with processing aids (without TCP) and PP-TCP composite (with processing aids) were evaluated and compared using standard dog bone samples. Uniaxial compression tests were performed on cylindrical porous samples with an average pore size of 160 mum and varying vol.% porosity (36%, 48% and 52%). Samples with 36 vol.% porosity showed the best compressive strength of 12.7 MPa. Cytotoxicity and cell proliferation studies were conducted with a modified human osteoblast cell-line (HOB). Results showed that these samples were non-toxic with excellent cell growth during the first two weeks of in vitro testing. (C) 2003 Elsevier B.V. All rights reserved.