Porous Hydroxyapatite-Polyhydroxybutyrate Composites Fabricated by a Novel Method Via Centrifugation
Porous hydroxyapatite-polyhydroxybutyrate (HA-PHB) composites were fabricated by infiltrating PHB micro-/nano-particles into rigid HA scaffolds via centrifugation, followed by subsequent heating at 175°C to melt the PHB into the scaffolds. HA scaffolds were obtained by heating trabecular bovine femur bone at 1,350°C to remove the organic and sinter the HA. PHB particles were recovered and purified from microbial cells by two different chemical methods, which either filled the apparent porosity of the scaffolds or coated the trabecular network of the scaffolds after heating. The mechanical properties, porosity, HA/PHB volume fractions and surface adhesion of the resulting HA-PHB composites were investigated and compared to the original HA scaffolds. The final porosities of the filled and coated composites were ~54% and ~67%, respectively. All of the HA-PHB composites showed a slight increase in strength with the addition of PHB. The filled composites showed no change in stiffness from the addition of PHB, while the coated composites showed an increase in stiffness over the original HA scaffolds from ~35 to ~105 MPa. The enhanced stiffness in the coated composites was due to strong interactions between its HA and PHB constituent phases. Very little inter-constituent adhesion was observed in the filled composites.
KeywordsHydroxyapatite scaffold Polyhydroxybutyrate particle Bone implant Biomimetic Centrifugation
This work was supported by the National Science Foundation, Ceramics Program Grant 1006931. We would like to thank Tina Carvalho (BEMF, UHM) for help with transmission electron microscopy and Ryan Anderson (CalIT2, UCSD) for help with scanning electron microscopy.
- 3.Launey ME, Buehler MJ, Ritchie RO (2010) On the mechanistic origins of toughness in bone. Annu Rev Mater Res 40:25–53, Annual Reviews: Palo AltoGoogle Scholar
- 6.Low KL et al (2010) Calcium phosphate-based composites as injectable bone substitute materials. J Biomed Mater Res B Appl Biomater 94B(1):273–286Google Scholar
- 7.Pielichowska K, Blazewicz S (2010) Bioactive polymer/hydroxyapatite (nano) composites for bone tissue regeneration. In: Biopolymers: lignin, proteins, bioactive nanocomposites. Springer, Berlin, pp 97–207Google Scholar
- 33.Hahn SK, Chang YK, Lee SY (1995) Recovery and characterization of poly(3-hydroxybutyric acid) synthesized in alcaligenes-eutrophus and recombinant escherichia-coli. Appl Environ Microbiol 61(1):34–39Google Scholar
- 39.Gibson LJ, Ashby MF (1999) Cellular solids: structure and properties, 2nd edn. Cambridge University Press, CambridgeGoogle Scholar