The Effect of Different Surface Modification Agents on the Dispersion of Nano-Hydroxyapatite (n-HA) Crystallites

Abstract:

Article Preview

The surface of synthetic calcium hydroxyapatite (HA, Ca10(PO4)6(OH)2) was modified through combining freeze-drying, solvent replacement and surface modification methods in an effort to obtain the deaggregative n-HA crystallites. Three surface modification agents: Polyethylene glycol (PEG, Mw: 6000), poly(propyl oxide)-poly (ethyl oxide)-co-poly(propyl oxide)(Pluronic F-127, Mw: 12,000) and poly(d, l-lactide)-co-poly (ethylene glycol) (PELA, Mw: 20,000)were selected. The dispersion of the modified n-HA was characterized by sedimentation time in distilled water, acetone and dimethyl formamide (DMF). The results indicate that the three surface modification agents influence the dispersion of n-HA crystallites in various solvent based on different mechanisms. Transmission electron microscopy (TEM) observation shows that the dried and acetone-replacement powders are composed of needle-like HA crystallites isolated individually. The chosen solvents have a profound effect on the sedimentation time. In distilled water, the dispersion of as-synthesized n-HA crystallites is increased greater by F127 than by PEG. After freeze-drying, the two n-HA particles show homogeneous dispersion in acetone. The colloid stability of freeze-dried HA/PEG, solution-replaced HA/F127 and solution-replaced HA/PELA in DMF were improved significantly. The suspensions remained stable after 30 days with only a blue transparent sol being observed.

Info:

Periodical:

Key Engineering Materials (Volumes 284-286)

Main Theme:

Edited by:

Panjian Li, Kai Zhang and Clifford W. Colwell, Jr.

Pages:

55-58

DOI:

10.4028/www.scientific.net/KEM.284-286.55

Citation:

Y.M. Jiang et al., "The Effect of Different Surface Modification Agents on the Dispersion of Nano-Hydroxyapatite (n-HA) Crystallites ", Key Engineering Materials, Vols. 284-286, pp. 55-58, 2005

Online since:

April 2005

Export:

Price:

$35.00

[1] R. Labella, M. Braden, S. Deb (1994) Biomaterials 15: 1197-1200.

[2] S. Weiner, H.D. Wagner (1998) Annu Rev Mater Sci 28: 271.

[3] X Deng, J.Y. Hao, C.S. Wang (2001) Biomaterials 22: 2867-73.

[4] L. Borum-Nicholas, O.C. Wilson Jr (2003) Biomaterials 21: 3671-79.

[5] C. M. Vaz, R.L. Reis, A.M. Cunha (2002) Biomaterials 23: 629-35.

[6] Q. Liu, J.R. de Wijn, C.A. van Blitterswijk (1997) Biomaterials 18: 1263-70.

[7] M. Jarcho, C.H. Bilen, M.B. Thomas, J. Bobick, J.F. Kay, R.H. Doremus (1976) J Mater Sci 11: 2027-(2035).

In order to see related information, you need to Login.