Fluorapatite/hydroxyapatite solid solution has better biological properties than other apatites, especially used as films or coatings. In this work, sol-gel preparation and in vitro behavior of fluorapatite/hydroxyapa...Fluorapatite/hydroxyapatite solid solution has better biological properties than other apatites, especially used as films or coatings. In this work, sol-gel preparation and in vitro behavior of fluorapatite/hydroxyapatite solid solution films on titanium alloy were investigated. Ca(NO3)2·4H2O and PO(OH)K(OEt)3-x. were selected as precursors, and hexafluorophosphoric acid (HPF6) was used as a fluorine containing reagent. The Ca and P precursors were mixed with HPF6 to keep the Ca/P molar ratio 1.67. The mixtures refluxed for 12 h were used as dipping sols for the preparation of the films. The phase of the films obtained at 600℃ was apatite. The F contents in the films increased with the concentrations of HPF6 in the dipping sols. The solid solution films were shown to have better stability than hydroxyapatite films, and a reasonably good bioactivity in the in vitro evaluation.展开更多
Hydroxyapatite is a type of calcium phosphate-based material with great interest for biomedical applications, due to the chemical similarity between this material and the mineral part of human bone. However, synthetic...Hydroxyapatite is a type of calcium phosphate-based material with great interest for biomedical applications, due to the chemical similarity between this material and the mineral part of human bone. However, synthetic hydroxyapatite is essentially brittle;the practice indicates that the use of hydroxyapatite without additives for implant production is not efficient, due to its low strength parameters. In the present work, biocomposites of hydroxyapatite-wollastonite were synthesized by an alternative sol-gel route, using calcium nitrate and ammonium phosphate as precursors of hydroxyapatite, and high purity natural wollastonite was added in ratios of 20, 50 and 80 percent by weight immersed in aqueous medium. Formation of hydroxyapatite occurs at a relatively low temperature of about 350?C, while the wollastonite remains unreacted. After that, these biocomposites were sintered at 1200?C for 5 h to produce dense materials. The characterization techniques demonstrated the presence of hydroxyapatite and wollastonite as unique phases in all products.展开更多
Hydrothermal and sol-gel synthesis methods have been used to prepare nano-particulate hydroxyapatite (HA) powders for detailed characterisation. Bulk elemental analysis data are compared from X-ray diffraction, X-ray ...Hydrothermal and sol-gel synthesis methods have been used to prepare nano-particulate hydroxyapatite (HA) powders for detailed characterisation. Bulk elemental analysis data are compared from X-ray diffraction, X-ray fluorescence and Fourier transform infrared spectroscopy. These show the presence of secondary phases in the sol-gel powders which can be attributed to evaporative loss of precursor phosphite phases during specimen preparation and breakdown of the primary HA phase during calcination. Only the primary HA phase is detected in the hydrothermally prepared powder. In addition, Ca/P ratios of each powder are determined at the particle level using transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM-EDX), having first established a threshold electron fluence below which significant electron-beam-induced alteration of the composition of HA does not occur. The TEM-EDX results show a greater compositional variability of particles from the sol-gel preparation route compared to the hydrothermal route. Overall it is the combination of the analysis techniques that shows the hydrothermal synthesis route produces near- stoichiometric, single phase, hydroxyapatite.展开更多
The concept of biocompatible, osteoconductive and noninflammatory material mimicking the structure of natural bone has generated a considerable interest in recent decades. Hydroxyapatite （HA） is an important bionic ...The concept of biocompatible, osteoconductive and noninflammatory material mimicking the structure of natural bone has generated a considerable interest in recent decades. Hydroxyapatite （HA） is an important bionic material that is used for bone grafting in osseous defects and drug carriers. HA with various morphologies and surface properties have been widely investi- gated. In this paper, HA nanofibers are produced through a combination of electrospinning and sol-gel technique. The mor- phologies, composition and structure are investigated by Scanning Electron Microscopy （SEM）, Thermogravimetic Analysis （TGA）, Fourier Transform Infrared （FTIR）, X-ray Diffraction （XRD） patterns, Transmission Electron Microscopy （TEM）. The results show that HA nanofibers are even and well-crystallized, and pH is crucial for producing HA nanofibers. With the change of pH from 4 to 9, nanofibers grow densely along （210） plane and become compact while surface area, pore volume and pore size decrease correspondingly. The synthesized HA nanofibers are nontoxic and safe. Zn can be also incorporated into HA nanofibers, which will endow them with more perfect function.展开更多
Hydroxyapatite (HA) is effectively used as a bioimplant material because it closely resembles bone apatite and exhibits good biocompatibility. This paper describe synthesis technique of HA powder by sol-gel method. Th...Hydroxyapatite (HA) is effectively used as a bioimplant material because it closely resembles bone apatite and exhibits good biocompatibility. This paper describe synthesis technique of HA powder by sol-gel method. The product was sintered twice at two different temperatures 400°C to 750°C to improve its crystallinity. The final powder sintered at two temperatures was characterized by X-ray analysis, Scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR) to reveal its phase content, morphology and types of bond present within it. Thermal analysis (TG–DTA) was carried out to investigate the thermal stability of the powder.展开更多
Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after whic...Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after which X-ray diffraction (XRD) analysis showed presence of combeite (Na2Ca2Si3O9) as the crystalline phase. In vitro bioactivity test conducted on the material using simulated body fluid (SBF) showed the formation of carbonated hydroxyapatite on its surface. The material during the SBF test was observed to transform from a mechanically strong crystalline phase Na2Ca2Si3O9 to an amorphous phase after incubation for 14 days indicating that the material was biodegradable. Scanning electron microscopy (SEM) was used to investigate the surface morphology, while Fourier transform infrared (FTIR) spectroscopy facilitated the confirmation of hydroxyapatite (HA) formation. The monolith material obtained may be a good candidate for application in tissue engineering scaffolds.展开更多
A rapid sol-gel method for preparing hydroxyapatite nanoparticles(nHAP) has been developed. Three different sets of experimental conditions, in terms of solvents(water and ethanol), synthesis temperatures(25, 40 and 6...A rapid sol-gel method for preparing hydroxyapatite nanoparticles(nHAP) has been developed. Three different sets of experimental conditions, in terms of solvents(water and ethanol), synthesis temperatures(25, 40 and 60℃), and microwave irradiation(on and off) were explored. Crystal phase composition, functional groups and morphology of the products were characterized by thermogravimetric analysis(TGA), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FT-IR), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The solvent and temperature were optimized based on product properties. Most importantly, the microwave-assisted method(with little to no ageing necessary) was much faster than the conventional methods(with slow ageing processes needing from hours to days), while affording pure nHAP with virtually identical morphological and structural properties. This study represents a practical application of the powerful microwave technique in synthesis of nHAP, offering guidance on the selection of optimum experiment conditions.展开更多
Hydroxyapatite powder was prepared by sol-gel method using the calcium nitrate tetrahydrate and pentoxide us reactant. The effects of main processing parameters such us reagent, concentration, temperature etc on the ...Hydroxyapatite powder was prepared by sol-gel method using the calcium nitrate tetrahydrate and pentoxide us reactant. The effects of main processing parameters such us reagent, concentration, temperature etc on the synthesis of hydroxyapatite were investigated. The synthetic mechanism was also studied. The results showed that main optimized parameters were us follows ： 2 M ethanol solution of P2 05 and 4 M ethanol solution Ca（ NO3 ）2 ·4H2O, 12- 24 h of aging time, 500℃ sintered temperature. X-ray diffraction and Fourier transform infrared spectra results showed that the mixtures were composed of amorphous hydroxyapatite, Ca （ NO3）2, PO（ OH）3-x（ OR）x, bellow 400℃. The pure hydroxyapatite powder were prepared at 500℃ for 30 nun. The aging of the sol influenced the purity greatly. The CaO phase was observed from the powder without aging. This process with cheap reactants was simple and the advantages offered by this process made it possible to produce the uniform fine powder in large quantity.展开更多
The main objective of the present work was to investigate the effect of surfactant type and synthesis temperature on the structure, porosity and the bioactivity of 92S6 (92% SiO2, 6% CaO, and 2% P2O5 mol %) mesoporous...The main objective of the present work was to investigate the effect of surfactant type and synthesis temperature on the structure, porosity and the bioactivity of 92S6 (92% SiO2, 6% CaO, and 2% P2O5 mol %) mesoporous sol-gel glasses. The aim was to provide a basis for controlling the bioactive behavior of the different 92S6 samples used for tissue regeneration and for biomedical engineering in order to obtain sufficient performances by controlling the porosity of the glass. In this paper, a series of mesoporous bioactive glasses were synthesized using three different surfactants (C10H20BrN, C19H42BrN, C22H48BrN) at different aging temperatures (20°C, 40°C and 60°C). The surfactant was removed by calcination, which was carried out by increasing the temperature to 650°C for 6 h. A comparison among these synthesized glasses was conducted and the research emphasis was placed on the synthesis temperature and the surfactant type dependence on the textural properties and particularly porosity that were ultimately responsible for glass bioactivity.展开更多
基金Zhejiang Provincial Natural Science Foundation of China(598061)the research fund of the Doctoral Program of Higher Education(98033536)China-Portugal Cooperation Project for supporting the work.
文摘Fluorapatite/hydroxyapatite solid solution has better biological properties than other apatites, especially used as films or coatings. In this work, sol-gel preparation and in vitro behavior of fluorapatite/hydroxyapatite solid solution films on titanium alloy were investigated. Ca(NO3)2·4H2O and PO(OH)K(OEt)3-x. were selected as precursors, and hexafluorophosphoric acid (HPF6) was used as a fluorine containing reagent. The Ca and P precursors were mixed with HPF6 to keep the Ca/P molar ratio 1.67. The mixtures refluxed for 12 h were used as dipping sols for the preparation of the films. The phase of the films obtained at 600℃ was apatite. The F contents in the films increased with the concentrations of HPF6 in the dipping sols. The solid solution films were shown to have better stability than hydroxyapatite films, and a reasonably good bioactivity in the in vitro evaluation.
文摘Hydroxyapatite is a type of calcium phosphate-based material with great interest for biomedical applications, due to the chemical similarity between this material and the mineral part of human bone. However, synthetic hydroxyapatite is essentially brittle;the practice indicates that the use of hydroxyapatite without additives for implant production is not efficient, due to its low strength parameters. In the present work, biocomposites of hydroxyapatite-wollastonite were synthesized by an alternative sol-gel route, using calcium nitrate and ammonium phosphate as precursors of hydroxyapatite, and high purity natural wollastonite was added in ratios of 20, 50 and 80 percent by weight immersed in aqueous medium. Formation of hydroxyapatite occurs at a relatively low temperature of about 350?C, while the wollastonite remains unreacted. After that, these biocomposites were sintered at 1200?C for 5 h to produce dense materials. The characterization techniques demonstrated the presence of hydroxyapatite and wollastonite as unique phases in all products.
文摘Hydrothermal and sol-gel synthesis methods have been used to prepare nano-particulate hydroxyapatite (HA) powders for detailed characterisation. Bulk elemental analysis data are compared from X-ray diffraction, X-ray fluorescence and Fourier transform infrared spectroscopy. These show the presence of secondary phases in the sol-gel powders which can be attributed to evaporative loss of precursor phosphite phases during specimen preparation and breakdown of the primary HA phase during calcination. Only the primary HA phase is detected in the hydrothermally prepared powder. In addition, Ca/P ratios of each powder are determined at the particle level using transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM-EDX), having first established a threshold electron fluence below which significant electron-beam-induced alteration of the composition of HA does not occur. The TEM-EDX results show a greater compositional variability of particles from the sol-gel preparation route compared to the hydrothermal route. Overall it is the combination of the analysis techniques that shows the hydrothermal synthesis route produces near- stoichiometric, single phase, hydroxyapatite.
基金The National Natural Science Foundation of China，The Natural Science Foundation of Jilin province，Education Department of Jilin
文摘The concept of biocompatible, osteoconductive and noninflammatory material mimicking the structure of natural bone has generated a considerable interest in recent decades. Hydroxyapatite （HA） is an important bionic material that is used for bone grafting in osseous defects and drug carriers. HA with various morphologies and surface properties have been widely investi- gated. In this paper, HA nanofibers are produced through a combination of electrospinning and sol-gel technique. The mor- phologies, composition and structure are investigated by Scanning Electron Microscopy （SEM）, Thermogravimetic Analysis （TGA）, Fourier Transform Infrared （FTIR）, X-ray Diffraction （XRD） patterns, Transmission Electron Microscopy （TEM）. The results show that HA nanofibers are even and well-crystallized, and pH is crucial for producing HA nanofibers. With the change of pH from 4 to 9, nanofibers grow densely along （210） plane and become compact while surface area, pore volume and pore size decrease correspondingly. The synthesized HA nanofibers are nontoxic and safe. Zn can be also incorporated into HA nanofibers, which will endow them with more perfect function.
文摘Hydroxyapatite (HA) is effectively used as a bioimplant material because it closely resembles bone apatite and exhibits good biocompatibility. This paper describe synthesis technique of HA powder by sol-gel method. The product was sintered twice at two different temperatures 400°C to 750°C to improve its crystallinity. The final powder sintered at two temperatures was characterized by X-ray analysis, Scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR) to reveal its phase content, morphology and types of bond present within it. Thermal analysis (TG–DTA) was carried out to investigate the thermal stability of the powder.
文摘Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after which X-ray diffraction (XRD) analysis showed presence of combeite (Na2Ca2Si3O9) as the crystalline phase. In vitro bioactivity test conducted on the material using simulated body fluid (SBF) showed the formation of carbonated hydroxyapatite on its surface. The material during the SBF test was observed to transform from a mechanically strong crystalline phase Na2Ca2Si3O9 to an amorphous phase after incubation for 14 days indicating that the material was biodegradable. Scanning electron microscopy (SEM) was used to investigate the surface morphology, while Fourier transform infrared (FTIR) spectroscopy facilitated the confirmation of hydroxyapatite (HA) formation. The monolith material obtained may be a good candidate for application in tissue engineering scaffolds.
基金National Key Research Program of China(2016YFA0201700/2016YFA02017001)National Natural Science Foundation of China(31400813)
文摘A rapid sol-gel method for preparing hydroxyapatite nanoparticles(nHAP) has been developed. Three different sets of experimental conditions, in terms of solvents(water and ethanol), synthesis temperatures(25, 40 and 60℃), and microwave irradiation(on and off) were explored. Crystal phase composition, functional groups and morphology of the products were characterized by thermogravimetric analysis(TGA), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FT-IR), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The solvent and temperature were optimized based on product properties. Most importantly, the microwave-assisted method(with little to no ageing necessary) was much faster than the conventional methods(with slow ageing processes needing from hours to days), while affording pure nHAP with virtually identical morphological and structural properties. This study represents a practical application of the powerful microwave technique in synthesis of nHAP, offering guidance on the selection of optimum experiment conditions.
文摘Hydroxyapatite powder was prepared by sol-gel method using the calcium nitrate tetrahydrate and pentoxide us reactant. The effects of main processing parameters such us reagent, concentration, temperature etc on the synthesis of hydroxyapatite were investigated. The synthetic mechanism was also studied. The results showed that main optimized parameters were us follows ： 2 M ethanol solution of P2 05 and 4 M ethanol solution Ca（ NO3 ）2 ·4H2O, 12- 24 h of aging time, 500℃ sintered temperature. X-ray diffraction and Fourier transform infrared spectra results showed that the mixtures were composed of amorphous hydroxyapatite, Ca （ NO3）2, PO（ OH）3-x（ OR）x, bellow 400℃. The pure hydroxyapatite powder were prepared at 500℃ for 30 nun. The aging of the sol influenced the purity greatly. The CaO phase was observed from the powder without aging. This process with cheap reactants was simple and the advantages offered by this process made it possible to produce the uniform fine powder in large quantity.
文摘The main objective of the present work was to investigate the effect of surfactant type and synthesis temperature on the structure, porosity and the bioactivity of 92S6 (92% SiO2, 6% CaO, and 2% P2O5 mol %) mesoporous sol-gel glasses. The aim was to provide a basis for controlling the bioactive behavior of the different 92S6 samples used for tissue regeneration and for biomedical engineering in order to obtain sufficient performances by controlling the porosity of the glass. In this paper, a series of mesoporous bioactive glasses were synthesized using three different surfactants (C10H20BrN, C19H42BrN, C22H48BrN) at different aging temperatures (20°C, 40°C and 60°C). The surfactant was removed by calcination, which was carried out by increasing the temperature to 650°C for 6 h. A comparison among these synthesized glasses was conducted and the research emphasis was placed on the synthesis temperature and the surfactant type dependence on the textural properties and particularly porosity that were ultimately responsible for glass bioactivity.
