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Novel Porous Hydroxyapatite Prepared by Combining H2O2 Foaming with PU Sponge and Modified with PLGA and Bioactive GlassSchool of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore
School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore,x.miao{at}qut.edu.au, School of Engineering Systems, Queensland University of Technology Brisbane, QLD 4001, Australia Porous hydroxyapatite (HA) scaffolds have been intensively studied and developed for bone tissue engineering, but their mechanical properties remain to be improved. The aim of this study is to prepare HA-based composite scaffolds that have a unique macroporous structure and special struts of a polymer/ceramic interpenetrating composite and a bioactive coating. A novel combination of a polyurethane (PU) foam method and a hydrogen peroxide (H2O 2) foaming method is used to fabricate the macroporous HA scaffolds. Micropores are present in the resulting porous HA ceramics after the unusual sintering of a common calcium phosphate cement and are infiltrated with the poly(D,L-lactic-co-glycolic acid) (PLGA) polymer. The internal surfaces of the macropores are further coated with a PLGA-bioactive glass composite coating. The porous composite scaffolds are characterized in terms of microstructure, mechanical properties, and bioactivity. It is found that the HA scaffolds fabricated by the combined method show high porosities of 6165% and proper macropore sizes of 200600 µm. The PLGA infiltration improved the compressive strengths of the scaffolds from 1.51.8 to 4.05.8 MPa. Furthermore, the bioactive glass-PLGA coating rendered a good bioactivity to the composites, evidenced by the formation of an apatite layer on the sample surfaces immersed in the simulated body fluid (SBF) for 5 days. The porous HA-based composites obtained from this study have suitable porous structures, proper mechanical properties, and a high bioactivity, and thus finds potential application as scaffolds for bone tissue engineering.
Key Words: hydroxyapatite porosity compressive strength bioactive glass poly(lactic-co-glycolic acid).
This version was published on April
1, 2007 Journal of Biomaterials Applications, Vol. 21, No. 4,
351-374 (2007) |
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