Synthesis of Nano - Hydroxyapatite and Nano - Fluoroapatite Particles by Sol-Gel Method (original) (raw)
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Synthesis of nano-fluorohydroxyapatite thin films by sol-gel method
Malaysian Journal of Science. Series B, Physical & Earth Sciences, 2010
It is realized that the surface of biomedical metallic implants covered by fluorohydroxyapatite,-alo(PO4)6(01-1, F)] (FHA) can create bioactivity of the implant and shorten healing time. In this work FHA, in the of powders and of thin films on titanium substrates, were synthesized by sol-gel spin coating method, using calcium nitrate tetrahydrate (Ca(NO3)2).4H20, phosphorous pentoxide (P205) and ammonium fluoride (NH4F) to vide Ca-precursor, P-precursor and fluorine reagent, respectively. The FHA powders were calcined and thin were fired at temperatures ranging from 500-800°C. The constituent of both powders and thin films were firmed as FHA using X-ray diffraction (XRD) and Fourier transform Infrared spectroscopy (FTIR). The thermal bility of FHA powders was studied by differential thermal analysis (DTA). The optimized calcination and firing temperature was 600 °C. Transmission electron microscopy (TEM) results with Debye-Scherrer equation gave the tie of the FHA particles in nano-scale range. The films were found to be quite uniform and dense by SEM.
2012
Hydroxyapatite (HA), fluor-hydroxyapatite (FHA) with varying levels of fluoride ion substitution and fluorapatite (FA) were synthesised by the sol-gel method as possible implant coating or bone-grafting materials. Calcium nitrate and triethyl phosphite were used as precursors under an ethanol-water based solution. Different amounts of ammonium fluoride were incorporated for the preparation of the FHA and FA sol-gels. After heating and powdering the sol-gels, dissolution behaviour was assessed using ion chromatography to measure Ca 2? and PO 4 3ion release. Biological behaviour was assessed using cellular proliferation with human osteosarcoma cells and alamarBlue TM assay. Statistical analysis was performed with a two way analysis of variance and post hoc testing with a Bonferroni correction. Increasing fluoride substitution into an apatite structure decreased the dissolution rate. Increasing the firing temperature of the HA, FHA and FA sol-gels up to 1,000°C decreased the dissolution rate. There was significantly higher cellular proliferation on highly substituted FHA and FA than on HA or Titanium. The properties of an implant coating or bone grafting material can be tailored to meet specific requirements by altering the amount of fluoride that is incorporated into the original apatite structure. The dissolution behaviour can further be altered by the temperature at which the sol-gel is fired.
Synthesis of hydroxyapatite/fluoroapatite solid solution by a sol–gel method
Materials Letters, 2001
Ž . A sol-gel method is developed to synthesize hydroxyapatite HA rfluoroapatite FA solid solution for providing a basis of preparation of the solid solution film or coating. Calcium nitrate-4 hydrate, phosphoric pentoxide and trifluoroacetic acid Ž . Ž . TFA were used as the precursors. Triethanolamine TEA was used as a promoter for incorporating fluorine into Ca phosphates. Mixed ethanol solutions of the Ca and P precursors in CarP ratio of 1.67 with different amounts of TFA and TEA were prepared; the mixed solutions were dried on a hot plate to convert them to the as-prepared powders. After the powders were calcined at temperatures up to 9008C, HArFA solid solutions were obtained. It was found that the fluorine contents in the apatite were dependent on the amounts of TFA and TEA in the mixed solutions. q
Synthesis and characterisation of hydroxy/fluoroapatite solid solution
Journal of Materials Science, 2001
Hydroxyapatite (HA) and fluoroapatite (FHA) have been widely investigated as bone substitute and replacement materials. We report here the preparation of hydroxy/fluoroapatite solid solution using wet chemical precipitation method via brushite hydrolysis. Various amounts of sodium fluoride (1–5 mol%) were added during the preparation of hydroxyapatite to form hydroxy/fluoroapatite solid solution. The various experimental techniques like XRD, DTA, TGA, FT-IR and Vicker's hardness measurements were used to characterize the synthesized powders. Thermal analysis of the samples shows only the decomposition reaction of residues formed and the corresponding weight loss due to these reactions. The XRD data of all the samples calcined at 900°C shows well defined peaks of hydroxyapatite and fluoroapatite. The merging of (211) and (112) peak of apatite lattice in the FHA pattern indicates the formation of hydroxy/fluoroapatite solid solution. The decrease in the a-axis of HA lattice parameter indicates the substitution of F−ion in the OH−site of HA lattice. The FT-IR spectroscopic studies of the samples confirms the substitution of the F−ion in the OH−site of the HA lattice. The Vicker's hardness measurement shows that the hardness value of hydroxy/fluoroapatite solid solution is greater than the hydroxyapatite.
Preparation and Characterization of Fluorohydroxyapatite Nanopowders Nonalkoxide Sol-gel Method
Digest Journal of Nanomaterials and Biostructures, 2010
In this work, Fluorohydroxyapatite (FHA) nanopowders were synthesized using nonalkoxide sol-gel method. Here calcium nitrate tetrahydrate Ca(NO3)2.4H2O, phosphorous pentoxide (P2O5) and ammonium fluoride (NH4F) were used to provide Caprecursor, P- precursor and fluorine reagent, respectively. The FHA powders were calcined at temperatures ranging from 500 to 800oC. The resultant products have been confirmed to be FHA (apatite phase) using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The thermal stability of FHA powders was studied through diffraction thermal analysis (DTA) and the optimized calcination temperature was found to be 600oC. The results of transmission electron microscopy (TEM) and Debye-Scherrer equation have shown that the sizes of the FHA particles were in the range of nano-scale.
Advances in Applied Ceramics, 2010
In this study, the effect of fluorine ion addition on the structural, thermal, mechanical and solubility characteristics of hydroxyapatite nanopowders was investigated. The fluorine substituted hydroxyapatite powders with compositions of Ca 5 (PO 4) 3 (OH) 12x F x [x50 (hydroxyapatite), x50?68 (fluorhydroxyapatite) and x50?97 (fluorapatite)] were prepared. The powders were uniaxially pressed and were formed as disc shape. Subsequently, sinterability and thermal stability of disc samples were compared together. Also the effects simultaneously of fluoride content and temperature on the lattice parameters, crystallites size, microstrain and microstructure of the samples were examined. The sintering density and flexural strength of these samples were evaluated with the sintering temperature. Finally, the in vitro dissolution studies of the apatite samples were performed at osteoclastic resorption conditions. The above mentioned experimental results showed that the fluorine content had significant impact on the sintering behaviour, densification and mechanical properties of the hydroxyapatite nanopowders.
Journal of Materials Science: Materials in Medicine, 2013
Hydroxyapatite (HA), fluor-hydroxyapatite (FHA) with varying levels of fluoride ion substitution and fluorapatite (FA) were synthesised by the sol-gel method as possible implant coating or bone-grafting materials. Calcium nitrate and triethyl phosphite were used as precursors under an ethanol-water based solution. Different amounts of ammonium fluoride were incorporated for the preparation of the FHA and FA sol-gels. After heating and powdering the sol-gels, dissolution behaviour was assessed using ion chromatography to measure Ca 2? and PO 4 3ion release. Biological behaviour was assessed using cellular proliferation with human osteosarcoma cells and alamarBlue TM assay. Statistical analysis was performed with a two way analysis of variance and post hoc testing with a Bonferroni correction. Increasing fluoride substitution into an apatite structure decreased the dissolution rate. Increasing the firing temperature of the HA, FHA and FA sol-gels up to 1,000°C decreased the dissolution rate. There was significantly higher cellular proliferation on highly substituted FHA and FA than on HA or Titanium. The properties of an implant coating or bone grafting material can be tailored to meet specific requirements by altering the amount of fluoride that is incorporated into the original apatite structure. The dissolution behaviour can further be altered by the temperature at which the sol-gel is fired.
J Ceram Process Res, 2008
Nanocrystalline hydroxyapatite (HA) powder was synthesized by a simple heating process involving simple chemical reaction. The characterization of the produced powder showed that the powder is nanosize with particle in the range of 30-70 mm in diameter and almost evenly spherical in shape. The powder also has a high surface area of 43.16 m 2 /g. Field Emission Scanning Electron Microscopy (FESEM) observation showed the crystallite and particle size become bigger with an increment of calcination temperature, indicating increasing of crystallinity. FESEM observation showed the particle size become bigger with an increment of calcinations temperature. It is in agreement with the crystallite size analysis, obtained by Scherer's formula and particle size analysis, measured by Nano-Sizer. X-ray Diffraction (XRD) and Fourier Transform Infra Red Spectroscopy (FTIR) analyses exhibited the same result, where HA phase was clearly observed at at various temperatures up to 600˚C. However, at temperature more than 600˚C, Tri calcium phosphate (TCP) phase appeared suppressing the HA phase, producing biphasic calcium phosphate.
IOSR Journal of Applied Chemistry, 2014
Hydroxyapatite Ca 10 (PO4) 6 (OH) 2 (HA) is an important biomaterial and is the principal inorganic constituent of bones and teeth. It is also used as implant in the human body. By this investigation, hydroxyapatite nanostructured (18-56 nm) powders were prepared using novel wet precipitation method with calcium hydroxide and orthophosphoric acid solution as calcium and phosphorus precursors respectively. The Ca/P molar ratios of initial reagents are equal to 2.5. The HA filtered was dried at 90°C and calcined to different temperatures (300-1000°C). X-ray diffraction and Fourier transform infra-red spectroscopy used to characterize the calcined powder. The calcination reveals HA nano-powders. The particle size and crystallinity increase with the temperature. We note the formation of CaO at 1000°C. The refinement of cells parameters was performed by Fullprof-suite program. Thermal analysis (TG-DTA) was carried out to investigate the thermal stability of the powder.
Synthesis of fluorapatite–hydroxyapatite nanoparticles and toxicity investigations
International Journal of Nanomedicine, 2011
In this study, calcium phosphate nanoparticles with two phases, fluorapatite (FA; Ca 10 (PO 4) 6 F 2) and hydroxyapatite (HA; Ca 10 (PO 4) 6 (OH) 2), were prepared using the solgel method. Ethyl phosphate, hydrated calcium nitrate, and ammonium fluoride were used, r espectively, as P, Ca, and F precursors with a Ca:P ratio of 1:72. Powders obtained from the sol-gel process were studied after they were dried at 80°C and heat treated at 550°C. The degree of crystallinity, particle and crystallite size, powder morphology, chemical structure, and phase analysis were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Zetasizer experiments. The results of XRD analysis and FTIR showed the presence of hydroxyapatite and fluorapatite phases. The sizes of the crystallites estimated from XRD patterns using the Scherrer equation and the crystallinity of the hydroxyapatite phase were about 20 nm and 70%, respectively. T ransmission electron microscope and SEM images and Zetasizer experiments showed an average size of 100 nm. The in vitro behavior of powder was investigated with mouse fibroblast cells. The results of these experiments indicated that the powders were biocompatibile and would not cause toxic reactions. These compounds could be applied for hard-tissue engineering.