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Synthesis of macroporous hydroxyapatite scaffolds for bone tissue engineering
Shi Hong Li1, Joost R De Wijn, Pierre Layrolle
1IsoTis NV, Prof. Bronkhorstlaan 10-D, Bilthoven, 3723 MB, The Netherlands. Shihong.li@isotis.com
Journal of Biomedical Materials Research
|May 10, 2002
Summary
Researchers developed a novel method for creating macroporous hydroxyapatite (HA) scaffolds. Using ammonium bicarbonate as a foaming agent successfully produced highly porous and interconnected HA structures suitable for implants.
Area of Science:
- Biomaterials Science
- Ceramic Engineering
- Tissue Engineering
Background:
- Hydroxyapatite (HA) is a key biomaterial for bone regeneration due to its osteoconductive properties.
- Fabricating macroporous HA with controlled interconnected porosity remains a challenge for implant applications.
- Existing methods often struggle with achieving high porosity without compromising structural integrity.
Purpose of the Study:
- To develop a novel, scalable method for preparing macroporous hydroxyapatite (HA) with enhanced porosity and pore interconnectivity.
- To investigate the efficacy of different foaming agent systems in achieving desired HA scaffold properties.
- To identify a suitable HA fabrication process for potential use in bone scaffolds and implants.
Main Methods:
- Dual-phase mixing of HA slurry and Polymethylmethacrylate (PMMA) resin, followed by pyrolytic removal of PMMA.
- Introduction of a foaming step using citric acid and bicarbonate salts (sodium, calcium, ammonium) prior to PMMA polymerization.
- Characterization of the resulting porous HA using Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Environmental Scanning Electron Microscopy with Energy Dispersive X-ray analysis (ESEM-EDX), and optical microscopy.
Main Results:
- Dual-phase mixing yielded HA with 50% porosity, limited by sample collapse upon increasing PMMA content.
- Foaming step increased porosity up to 70% with interconnected pores for all tested bicarbonate systems.
- Only the ammonium bicarbonate system produced HA free from alkalic residues, making it suitable for biomedical applications.
- FTIR, XRD, ESEM-EDX, and microscopy confirmed the porous structure and chemical composition of the HA scaffolds.
Conclusions:
- A modified dual-phase mixing method incorporating ammonium bicarbonate foaming is effective for producing macroporous HA with high, interconnected porosity.
- The developed HA scaffolds possess suitable characteristics for potential use as bone implants.
- This method offers a promising route for fabricating advanced HA-based biomaterials for regenerative medicine.