"Hollow HA microspheres were prepared by converting Li₂O-CaO-B₂O₃ glass microspheres in a K₂HPO₄ solution. Process parameters, such as reaction temperature (25°C-60°C) and concentration of the phosphate solution (0.02-0.25 M) significantly influenced the microstructure of the hollow HA microspheres. Microspheres with the largest hollow core size were obtained at lower temperature or with low K₂HPO₄ concentration. In comparison, microspheres with high surface area (~140 m²/g) were obtained at higher K₂HPO₄ concentration (0.25 M). Upon heat treatment (up to 900°C), the surface area of the hollow HA microspheres decreased (from ~100 m²/g to ~2 m²/g), and the rupture strength increased (from ~11 MPa to ~30 MPa). The release kinetics of a model protein, bovine serum albumin (BSA) from the hollow HA microspheres were evaluated in two different media, phosphate-buffered saline (PBS) and poly(ethylene glycol) (PEG) hydrogel, used to mimic different environments in vivo. Implants composed of individual hollow HA microspheres or three-dimensional (3D) scaffolds composed of hollow HA microspheres were evaluated for their ability to regenerate bone in non-healing rat calvarial defects. The individual microspheres showed better ability to regenerate bone than the 3D scaffolds. Larger microspheres (150-250 µm in diameter) showed better ability to regenerate bone than smaller microspheres (106-150 µm). Loading the hollow HA microspheres with transforming growth factor-ß1 (TGF-ß1) (5 µg/defect) enhanced bone regeneration in the implants after 6 weeks. The results indicate that implants composed of hollow HA microspheres could potentially be used as an osteoconductive matrix for local growth factor delivery in bone regeneration"--Abstract, page iv.
Rahaman, M. N., 1950-
Day, D. E.
Brow, Richard K.
Brown, Roger F.
Bonewald, Lynda F.
Materials Science and Engineering
Ph. D. in Materials Science and Engineering
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Effect of Process Variables on the Microstructure of Hollow Hydroxyapatite Microspheres Prepared by A Glass Conversion Method
- Effect of Pyrophosphate Ions on the Conversion of Calcium-Lithium-Borate Glass to Hydroxyapatite in Aqueous Phosphate Solution
- Hollow Hydroxyapatite Microspheres as a Device for Local Delivery of Proteins
- Evaluation of Protein Release Behavior from Hollow Hydroxyapatite Microspheres into PEG Hydrogel
- Evaluation of Bone Regeneration in Implants Composed of Hollow HA Microspheres Loaded with TGF–ß1 in a Rat Calvarial Defect Model
- Long-term Conversion of 45S5 Bioactive Glass–Ceramic Microspheres in Aqueous Phosphate Solution
xviii, 203 pages
© 2012 Hailuo Fu, All rights reserved.
Dissertation - Open Access
Print OCLC #
Electronic OCLC #
Link to Catalog Record
Fu, Hailuo, "Hollow hydroxyapatite microspheres as devices for controlled delivery of proteins and as scaffolds for tissue engineering" (2012). Doctoral Dissertations. 2363.