The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hyd...The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hydroxyapatite of high crystallinity powder including trace Ca 10 (PO 4) 6CO 3(OH) and Ca 9HPO 4(PO 4) 6OH can be synthesized by mechanical activation without further thermal treatment at a high temperature. The synthesis reaction during the grinding process was almost completed within 1h. The as-ground powder exhibits a particle distribution of 20-100nm in size with a spherical or rodlike morphology. The composition and degree of crystallinity of the mechanochemical synthesized hydroxyapatite powders were coincident with the cement-type hydroxyapatite.展开更多
To study the effect of electrolytic concentration,bioactive ceramic films containing Ca and P on the surface of the Ti6Al4V alloy were prepared by micro-arc oxidation(MAO) in aqueous solutions of different concentrati...To study the effect of electrolytic concentration,bioactive ceramic films containing Ca and P on the surface of the Ti6Al4V alloy were prepared by micro-arc oxidation(MAO) in aqueous solutions of different concentrations.Composition,micro-morphology,wettability of the films and their corrosion behavior in a Hank's SBF were studied.Our experimental results show that the film is mainly composed of anatase,rutile and amorphous phases.With an increase in electrolytic concentration,the ratio of rutile in films enlarge and small amounts of calcium phosphate(Ca3(PO4)2) and hydroxyapatite(HA) appear.The number of micropores in films increases but their dimensions decrease and their porosities increase slightly.As the surface roughness of MAO film increases with concentration,the wettablility of the oxide film improves continually,while micro-hardness increases at first and then decreases.MAO treatment clearly improves the corrosion resistance of substrates in a Hank's SBF.展开更多
Fluorine-doped hydroxyapatite(FHA) and calcium deficient hydroxyapatite(CDHA) were coated on the surface biodegradable magnesium alloy using electrochemical deposition(ED) technique. Coating characterization was inves...Fluorine-doped hydroxyapatite(FHA) and calcium deficient hydroxyapatite(CDHA) were coated on the surface biodegradable magnesium alloy using electrochemical deposition(ED) technique. Coating characterization was investigated X-ray diffraction(XRD), Fourier-transformed infrared spectroscopy(FTIR), transmission electron microscopy(TEM), scanni electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS). The result shows that nano-FHA coated samp presents nano needle-like structure, which is oriented perpendicular to the surface of the substrate with denser and more unifo layers compared to the nano-CDHA coated sample. The nano-FHA coating shows smaller crystallite size(65 nm) compared to t nano-CDHA coating(95 nm); however, CDHA presents thicker layer(19 μm in thickness) compared to the nano-FHA(15 μm thickness). The corrosion behaviour determined by polarization, immersion and hydrogen evolution tests indicates that the nano-FH and nano-CDHA coatings significantly decrease corrosion rate and induce passivation. The nano-FHA and nano-CDHA coatings c accelerate the formation of bone-like apatite layer and significantly decrease the dissolution rate as compared to the uncoated M alloy. The nano-FHA coating provides effective protection to Mg alloy and presents the highest corrosion resistance. Therefore, t nano-FHA coating on Mg alloy is suggested as a great candidate for orthopaedic applications.展开更多
To explore the preparative method an d study the degradation characteristics of bone repair composite of DL polylac tic acid (PDLLA)/hydroxyapatite(HA)/decalcifying bone matrix (DBM) in vitro. Methods: An emulsion ble...To explore the preparative method an d study the degradation characteristics of bone repair composite of DL polylac tic acid (PDLLA)/hydroxyapatite(HA)/decalcifying bone matrix (DBM) in vitro. Methods: An emulsion blend method was developed to prepare the composite of PDLLA/HA/DBM in weight ratio of PDLLA:HA:DBM= 1.5 2 : 1 1.5 : 1. The dynamic changes of weight, biomechanical property and pH value of PDLLA/ HA/DBM and PDLLA in phosphate buffered saline (PBS, pH 7.4 ) were studied re spectively through degradation tests in vitro. Results: Without being heated, PDLLA, HA and DBM could be synt hesized with the emulsion blend method as bone composite of PDLLA/HA/DBM, which had both osteoconductive and osteoinductive effects. The diameter of the apertu re was 100 400 μm and the gap rate was 71.3 %. During degradation, the pH v alue of PDLLA solution decreased lightly within 2 weeks, but decreased obviously at the end of 4 weeks and the value was 4.0 . While the pH value of PDLLA/H A/DBM kept quite steady and was 6.4 at the end of 12 weeks. The weight of PDLLA changed little within 4 weeks, then changed obviously and was 50% of its initia l weight at the end of 12 weeks. While the weight of PDLLA/HA/DBM changed little within 5 weeks, then changed obviously and was 60% of the initial weight at the end of 12 weeks. The initial biomechanical strength of PDLLA was 1.33 MPa, decreased little within 3 weeks, then changed obviously and kept at 0.11 MP a at the end of 12 weeks. The initial biomechanical strength of PDLLA/HA/DBM was 1.7 MPa, decreased little within 4 weeks, then changed obviously and kept at 0.21 MPa at the end of 12 weeks. Conclusions: The emulsion blend method is a new method to prepa re bone repair materials. As a new bone repair material, PDLLA/HA/DBM is more su itable for regeneration and cell implantation, and the environment during its de gradation is advantageous to the growth of bone cells.展开更多
Seeding cells and scaffolds play pivotal roles in bone tissue engineering and regenerative medicine.Wharton’s jelly-derived mesenchymal stem cells(WJCs)from human umbilical cord represent attractive and promising see...Seeding cells and scaffolds play pivotal roles in bone tissue engineering and regenerative medicine.Wharton’s jelly-derived mesenchymal stem cells(WJCs)from human umbilical cord represent attractive and promising seeding cells in tissue regeneration and engineering for treatment applications.This study was carried out to explore the biocompatibility of scaffolds to seeding cells in vitro.Rod-like nano-hydroxyapatite(RN-HA)and flake-like micro-hydroxyapatite(FM-HA)coatings were prepared on Mg-Zn-Ca alloy substrates using micro-arc oxidation and electrochemical deposition.WJCs were utilized to investigate the cellular biocompatibility of Mg-Zn-Ca alloys after different surface modifications by observing the cell adhesion,morphology,proliferation,and osteoblastic differentiation.The in vitro results indicated that the RN-HA coating group was more suitable for cell proliferation and cell osteoblastic differentiation than the FM-HA group,demonstrating better biocompatibility.Our results suggested that the RN-HA coating on Mg-Zn-Ca alloy substrates might be of great potential in bone tissue engineering.展开更多
文摘The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hydroxyapatite of high crystallinity powder including trace Ca 10 (PO 4) 6CO 3(OH) and Ca 9HPO 4(PO 4) 6OH can be synthesized by mechanical activation without further thermal treatment at a high temperature. The synthesis reaction during the grinding process was almost completed within 1h. The as-ground powder exhibits a particle distribution of 20-100nm in size with a spherical or rodlike morphology. The composition and degree of crystallinity of the mechanochemical synthesized hydroxyapatite powders were coincident with the cement-type hydroxyapatite.
基金Projects 50535050 supported by the National Natural Science Foundation of ChinaNCET-06-0479 by the Program for New Century Excellent Talents in University of China
文摘To study the effect of electrolytic concentration,bioactive ceramic films containing Ca and P on the surface of the Ti6Al4V alloy were prepared by micro-arc oxidation(MAO) in aqueous solutions of different concentrations.Composition,micro-morphology,wettability of the films and their corrosion behavior in a Hank's SBF were studied.Our experimental results show that the film is mainly composed of anatase,rutile and amorphous phases.With an increase in electrolytic concentration,the ratio of rutile in films enlarge and small amounts of calcium phosphate(Ca3(PO4)2) and hydroxyapatite(HA) appear.The number of micropores in films increases but their dimensions decrease and their porosities increase slightly.As the surface roughness of MAO film increases with concentration,the wettablility of the oxide film improves continually,while micro-hardness increases at first and then decreases.MAO treatment clearly improves the corrosion resistance of substrates in a Hank's SBF.
文摘Fluorine-doped hydroxyapatite(FHA) and calcium deficient hydroxyapatite(CDHA) were coated on the surface biodegradable magnesium alloy using electrochemical deposition(ED) technique. Coating characterization was investigated X-ray diffraction(XRD), Fourier-transformed infrared spectroscopy(FTIR), transmission electron microscopy(TEM), scanni electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS). The result shows that nano-FHA coated samp presents nano needle-like structure, which is oriented perpendicular to the surface of the substrate with denser and more unifo layers compared to the nano-CDHA coated sample. The nano-FHA coating shows smaller crystallite size(65 nm) compared to t nano-CDHA coating(95 nm); however, CDHA presents thicker layer(19 μm in thickness) compared to the nano-FHA(15 μm thickness). The corrosion behaviour determined by polarization, immersion and hydrogen evolution tests indicates that the nano-FH and nano-CDHA coatings significantly decrease corrosion rate and induce passivation. The nano-FHA and nano-CDHA coatings c accelerate the formation of bone-like apatite layer and significantly decrease the dissolution rate as compared to the uncoated M alloy. The nano-FHA coating provides effective protection to Mg alloy and presents the highest corrosion resistance. Therefore, t nano-FHA coating on Mg alloy is suggested as a great candidate for orthopaedic applications.
文摘To explore the preparative method an d study the degradation characteristics of bone repair composite of DL polylac tic acid (PDLLA)/hydroxyapatite(HA)/decalcifying bone matrix (DBM) in vitro. Methods: An emulsion blend method was developed to prepare the composite of PDLLA/HA/DBM in weight ratio of PDLLA:HA:DBM= 1.5 2 : 1 1.5 : 1. The dynamic changes of weight, biomechanical property and pH value of PDLLA/ HA/DBM and PDLLA in phosphate buffered saline (PBS, pH 7.4 ) were studied re spectively through degradation tests in vitro. Results: Without being heated, PDLLA, HA and DBM could be synt hesized with the emulsion blend method as bone composite of PDLLA/HA/DBM, which had both osteoconductive and osteoinductive effects. The diameter of the apertu re was 100 400 μm and the gap rate was 71.3 %. During degradation, the pH v alue of PDLLA solution decreased lightly within 2 weeks, but decreased obviously at the end of 4 weeks and the value was 4.0 . While the pH value of PDLLA/H A/DBM kept quite steady and was 6.4 at the end of 12 weeks. The weight of PDLLA changed little within 4 weeks, then changed obviously and was 50% of its initia l weight at the end of 12 weeks. While the weight of PDLLA/HA/DBM changed little within 5 weeks, then changed obviously and was 60% of the initial weight at the end of 12 weeks. The initial biomechanical strength of PDLLA was 1.33 MPa, decreased little within 3 weeks, then changed obviously and kept at 0.11 MP a at the end of 12 weeks. The initial biomechanical strength of PDLLA/HA/DBM was 1.7 MPa, decreased little within 4 weeks, then changed obviously and kept at 0.21 MPa at the end of 12 weeks. Conclusions: The emulsion blend method is a new method to prepa re bone repair materials. As a new bone repair material, PDLLA/HA/DBM is more su itable for regeneration and cell implantation, and the environment during its de gradation is advantageous to the growth of bone cells.
基金supported by the National Natural Science Foundation of China(81071008,81171177,and 30870634)the Strategic Priority Re-search Program of the Chinese Academy of Sciences(XDA01030300)+3 种基金the Program for New Century Excellent Talents in University(NCET-06-0611)the Excellent Youth Foundation of Henan Scientific Committee(114100510005)the Young Excellent Teachers in University Funded Projects of Henan ProvinceBureau of Science and Technology Development Project from Henan Province(122102310203)
文摘Seeding cells and scaffolds play pivotal roles in bone tissue engineering and regenerative medicine.Wharton’s jelly-derived mesenchymal stem cells(WJCs)from human umbilical cord represent attractive and promising seeding cells in tissue regeneration and engineering for treatment applications.This study was carried out to explore the biocompatibility of scaffolds to seeding cells in vitro.Rod-like nano-hydroxyapatite(RN-HA)and flake-like micro-hydroxyapatite(FM-HA)coatings were prepared on Mg-Zn-Ca alloy substrates using micro-arc oxidation and electrochemical deposition.WJCs were utilized to investigate the cellular biocompatibility of Mg-Zn-Ca alloys after different surface modifications by observing the cell adhesion,morphology,proliferation,and osteoblastic differentiation.The in vitro results indicated that the RN-HA coating group was more suitable for cell proliferation and cell osteoblastic differentiation than the FM-HA group,demonstrating better biocompatibility.Our results suggested that the RN-HA coating on Mg-Zn-Ca alloy substrates might be of great potential in bone tissue engineering.
