Synthesis And Characterization Of Sol-Gel Derived Hydroxyapatite, Fluor-Hydroxyapatite And Fluor Apatite Nano Powders

Farsadzadeh, Babak; Behnamghader, Ali Asghar; Joughedust, Sedighe

doi:10.22041/ijbme.2009.13395

Synthesis And Characterization Of Sol-Gel Derived Hydroxyapatite, Fluor-Hydroxyapatite And Fluor Apatite Nano Powders

Document Type : Full Research Paper

Authors

Babak Farsadzadeh ¹

Ali Asghar Behnamghader ²

Sedighe Joughedust ¹

¹ Instructor, Engineering School, Shahrood Branch, Islamic Azad University

² Assistant Professor, Biomaterial Group, Materials and Energy Research Center

https://doi.org/10.22041/ijbme.2009.13395

Abstract

In this study hydroxyapatite (HA), flour-hydroxyapatite (FHA) and fluorapatite (FA) nanopowders synthesized by sol-gel route. Theses powders are used as biocompatible materials for bone replacement and teeth restoration. Ammonium fluoride (NH4F MERK), calcium nitrate [Ca(NO3)2,4H2O MERK] and triethyl phosphite [TEP, (C2H5O) 3P MERK)] were used as F, Ca and P precursors respectively. Triethyl phosphite was first hydrolyzed in ethanol with a small amount of distilled water. To prepare FHA and FA, an appropriate amount of the NH4F powder was added directly to TEP solution. The appropriate amounts of TEP solution was added dropwise to the calcium nitrate solution to yield a stoichiometric ratio of Ca/P=1.67. The resulted solution stirred for 1 h and aged at 25°C for 24 h and 40°C for 72h afterward. After oven drying at 80°C, the powder samples were heat-treated at 550°C for 1 h in air. Microstructural characteristics, powder morphology, chemical structure and phase analysis and in vitro study were performed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), Zetasizer instrument and cell culture method. Fluoride-substituted hydroxyapatite powders (FHA) and Fluor apatite (FA) were successfully fabricated via a sol–gel technique with the incorporation of different levels of fluoride ions. Nearly complete substitution of the OH¯ by F¯ occurred with heat treatment, which was confirmed by FTIR analysis. The particle size distribution of powders evaluated by a zeta-sizer instrument was 100-160nm. The XRD results showed that the crystal size of powders is 20-50nm. The phase stability and crystallinity were different depending on the level of fluoride substitution. Moreover, the crystallinity and crystallite size of the powders increased with fluoride substitution. These improvements in the crystallization and phase stability of the apatite structure, resulting from the fluoride substitution via the sol– gel process, suggest enhanced performance of the FHA powders. The cellular response to the HA, FHA and FA powder was assessed by an in vitro culture method using fibroblastic L929 cells. After culturing for 3 days, the results showed that the number of cells increased with increasing fluoride substitution.

Keywords

Hydroxyapatite

Fluor-Hydroxyapatite

Fluor Apatite

Nano powder

Sol-gel

Subjects

Nano-Biomaterials

[1] Hench L.L. and Ethridge E. C., Biomaterials: An Interfacial Approach. Academic Press, New York, 1982.

[2] Legeros R. Z., Apatites in Biological Systems, Prog. Cryst. Growth Charact., 1981; 4: 1–45 .

[3] Denissen H. W., Kalk W., Nieuport H. M., Mangano C., and Maltha J. C., Preparation-Induced Stability of Bioactive Apatite Coatings, Int. J. Prosthodont., 1991; 4: 432–39.

[4] Legeros RZ., Silverstone LM., Daculsi G., Kerebel LM., In vitro caries-like lesion formation in Fcontaining tooth enamel, J Dent Res, 1985; 62: 138– 44.

[5] Aoba T., The effect of fluoride on apatite structure and growth, Crit Rev Oral Biol, 1997; 8 (2):136–53.

[6] Moreno E. C., Kresak M., and Zahradnik R. T., Fluoridated Hydroxyapatite Solubility and Caries Formation, Nature (London), 1974; 247: 64–65.

[7] Hae-Won Kim, Long-Hao Li, Young-Hag Koh, Jonathan C. Knowles, and Hyoun-Ee Kim, Sol–Gel Preparation and Properties of Fluoride-Substituted Hydroxyapatite Powders, J. Am. Ceram. Soc., 2004; 87: 1939–1944.

[8] Kim H.-W., Koh Y.-H., Yoon B.-H., and Kim H.-E., Reaction Sintering and Mechanical Properties of Hydroxyapatite Zirconia Composite with CaF2 Additions, J. Am. Ceram. Soc., 2002; 85 (6): 1634–36.

[9] H.-W. Kim, Y.-M. Kong, Y.-H. Koh, H. E. Kim, H.- M. Kim, and J. S. Ko, Pressureless Sintering, Mechanical and Biological Properties of Fluorhydroxyapatite Composites with Zirconia, J. Am. Ceram. Soc., 2003; 86 (12): 2019–26.

[10] Okazaki M., Miake Y., Tohda H., Yanagisawa T., and Takahashi J., Differences in Solubility of Two Types of Heterogeneous Fluoridated Hydroxyapatites, Biomaterials, 1998;19: 611–16.

[11] Joa L. J., Best S. M., Knowles J. C., Rehman I., Santos J. D., and Bonfield N., Preparation and Characterization of Fluoride Substituted Apatites, J. Mater. Sci. Mater. Med., 1997; 8: 185–91.

[12] Schwarz James A., Contescu Cristian I., Putyera K., Dekker Encyclopedia of nanoscience and Nanotechnology, 2004; 13: 1797-2676.

[13] Overgaard S., Lind M., Grundvig H., Biinger C., and Soballe K., Hydroxyapatite and Fluorapatite Coatings for Fixation of Weight Loaded Implants, Clin. Orthop. Rel. Res., 1997; 336: 286–96.

[14] Slosarczyk A., Stobierska E., Paszkiewicz Z., and Gawlick M., Calcium Phosphate Materials Prepared from Precipitates with Various Calcium: Phosphorus Molar Ratios, J. Am. Ceram. Soc., 1996; 79 (10): 2539–44.

[15] Yoshimura M., Suda H., Okamoto K., and Ioku K., Hydrothermal Synthesis of Biocmpatible Whiskers, J. Mater. Sci., 1994; 29: 3399–402.

[16] Weng W. and Baptista J. L., Sol-Gel Derived Porous Hydroxyapatite Coatings, J. Mater. Sci. Mater. Med., 1998; 9: 159–63.

[17] Liu D.-M., Troczynski T., and Tseng W. J., Water- Based Sol-Gel Synthesis of Hydroxyapatite: Process Development, Biomaterials, 2001; 22: 1721–30.

[18] Joughehdoust S., Behnamghader A., and Manafi S., Effect of Aging Temperature on Formation of Sol–Gel Derived Fluor Hydroxyapatite Nanoparticles, J. Nanosci and Nanotech, 2010; 10: 2892-96.

[19] Landi E., Tampieri A., Celotti G., and Sprio S., Densification Behaviour and Mechanisms of Synthetic Hydroxyapatites, J. Eur. Ceram. Soc., 2000; 20: 2377– 87.

[20] Jenkins R. and Snyder R. L., Introduction to X-ray Powder Diffractomerty. John Wiley & Sons, New York, 1996.

[21] Z. LeGeros R., and P. Legeros J., New York University College of Dentistry, An introduction to bioceramics, chapter 9, 2004; 139-14.

[22] Smith D. K., Calcium Phosphate Apatites in Nature, in Hydroxyapatite and Related Materials. Edited by Brown P. W. and Constantz B., CRC Press, London, U.K., 1994: 29–44.

[23] Elliott J. C., Structure and Chemistry of the Apatites and Other Calcium Orthophospahtes, Elsevier, Amsterdam, Netherlands, 1994: 2-8.

[24] Landi E., Tampieri A., Celotti G., and Sprio S., Densification Behaviour and Mechanisms of Synthetic Hydroxyapatites, J. Eur. Ceram. Soc., 2000; 20: 2377– 87.

[25] Luis M., Rodriguez L, Judy N. H., and Gross K. A., J. Phys. Chem., B107 8316, 2003.

[26] Chirantha P. R., synthesis and characterization of strontium fluorapatite, Master of Science Degree in Chemistry, Department of Chemistry College of Sciences, Graduate College University of Nevada, Las Vegas, August 2005.

[27] Cheng K., Weng W., Qu H., Piyi Du., Shen G., Han G., Yang J., F. Ferreira J. M., Sol-gel preparation and in vitro test of fluorapatite/hydroxyapatite films, Department of Material Science and Engineering, Zhejiang University Hangzhou, 310027, China, August 2003.