Fabricating Hydroxyapatite Spherulites with Characteristic Microporous Structure by Chitin Sol Emulsified in Oil and Gelatinized In Situ
Hydroxyapatite (HA) spherulites had been fabricated successfully through a novel approach including chitin emulsion and geletion processes. The freeze-dried nano-HA powder was firstly dispersed in the chitin solvent before chitin dissolves in its solvent completely. The chitin sol containing nano-HA particles was dropped into oil and emulsified making use of liquids immiscibility effect between oil and chitin sol by stirring. The n-HA/Chitin sol spherulites gelled in situ with the existence of water molecules. Subsequently, the spherular gel granules were rinsed in distilled water to leach the solvent and dried in room circumstance. Finally, special sintering routines were carried to harvest spherular HA granules. The size and porosity of HA spherulites were controlled by the rate of nano-HA to chitin, the chitin concentration in the starting slurry, the stirring rate and the temperature of oil etc. In addition porosifier such as sugar was used in order to adjust the macro- and micro-porous structures in the HA spherulites. The morphological observation showed that the HA spherulites had good sphericity and characteristic microporous structure which were favorable for medical application.
Panjian Li, Kai Zhang and Clifford W. Colwell, Jr.
Q. Peng et al., "Fabricating Hydroxyapatite Spherulites with Characteristic Microporous Structure by Chitin Sol Emulsified in Oil and Gelatinized In Situ ", Key Engineering Materials, Vols. 284-286, pp. 419-422, 2005