Chitosan-hydroxyapatite （CS-HA） composite powders were synthesized via in situ co-precipitation method, through the reaction of Ca（NO3）2 and H3PO4 in the simulated body fluid （SBF） containing appropri- ate amoun...Chitosan-hydroxyapatite （CS-HA） composite powders were synthesized via in situ co-precipitation method, through the reaction of Ca（NO3）2 and H3PO4 in the simulated body fluid （SBF） containing appropri- ate amount of chitosan. The thermal evolution, microstructure and morphology were studied by TG-DTA （thermogravimetry-differential thermal analysis）, XRD （X-ray diffraction）, FTIR （Fourier transform infrared spectroscopy） and TEM （transmission electron microscopy）. The in vitro bioactivity test showed that the obtained CS-HA composites had higher capability of inducing calcium ions deposition. Effects of CS-HA com- posites on the bioactivity and compressive strength of bioglass bone cement were investigated. The results indicated that the bioactivity of bioglass bone cement could be improved further when CS-HA composite pow- ders were added into the cement, and appropriate amount of CS-HA additive was favorable for compressive strength improvement of bioglass bone cement.展开更多
To discuss the feasibility of bydroxyapatite bone cement （HAC） used as a drug delivery carrier and observe the bacteriostatic activity of HAC/ Norvancomycin（ HAC/ NVCM ） composite in vitro and its release charac...To discuss the feasibility of bydroxyapatite bone cement （HAC） used as a drug delivery carrier and observe the bacteriostatic activity of HAC/ Norvancomycin（ HAC/ NVCM ） composite in vitro and its release characteristics in vivo. Bacteriostatic zone and cycle of composite containing 1.5wt% of NVCM were measured in vitro studies. In vivo stndies , the composite was implanted into the top of rabbit＇ s tibia as the local medication group, HAC without NVCM being composed was also implanted and NVCM was injected into auricular vein as the systemic medication group. Cnncentrations of NVCM in blood and local bone were measured in both groups at different time points. The experimental results showed that HAC did not influence the bacteriostatic activity of NVCM otviously, and NVCM exist in the porosities of HAC in the pattern of amorphism. The blood coueemrations of NVCM in local medication group were always lower than those in systemic medication group at any time point, while the bone concentrations of NVCM in local medication group were much higher than those of systemic medication group,which remained to be 3.96μg/mg/mL after 2 weeks. And HAC has good release characteristics as a drug delivery earricr.展开更多
Objective: To prepare hydroxyapatite cement (or calcium phosphate cement, CPC) and analyze its capability. Methods: Tetracalcium phosphate (TTCP) was prepared by the method of high heat. TTCP reacted with in simulated...Objective: To prepare hydroxyapatite cement (or calcium phosphate cement, CPC) and analyze its capability. Methods: Tetracalcium phosphate (TTCP) was prepared by the method of high heat. TTCP reacted with in simulated body situation and produced CPC, Its capability was analyzed by scanning electron microscopy (SEM) , X-ray diffraction(XRD). Its density, absorbing water coefficient, macroporosity and campressive strength were measured also. Results: The main element of CPC is hydroxyapatite (HA) , its microstructure comprised of needlelike or petal crystals. The diameter of micropore was 4-10 nm, density was 1.922 g/cm3, macroporosity was 29. 777% , absorbing coefficient was 15. 503%, compressive strength was 42. 70 Mpa. Conclusion: This CPC has three-dimensional spatial structure, its strength meets the need of cancellous bone grafting.展开更多
Glass based bone cement (GBC) was synthesized by mixing CaO-SiO2-P2O5 based glass powder with ammonium phosphate liquid medium. Bone-like hydroxyapatite (HAP, Ca10(PO4)6(OH)2) was found to form after GBC was immersed ...Glass based bone cement (GBC) was synthesized by mixing CaO-SiO2-P2O5 based glass powder with ammonium phosphate liquid medium. Bone-like hydroxyapatite (HAP, Ca10(PO4)6(OH)2) was found to form after GBC was immersed in simulated body fluid (SBF). HAP crystal grew with an increasing time along c axle and reached about 200 nm in length after 30 days, however, the end plane granularity remained 30-50 nm. The chemical composition, crystal structure and morphology of HAP formed from GBC were proved to have great resemblance with living HAP. It is believed that GBC was a desirabie biomedicai material with high bioactivity. Furthermore, the high compressive strength guaranteed the possibility of GBC in clinical application.展开更多
Calcium phosphate cements have received much attention in recent decades owing to their biocompatibility, in situ handling, and shaping abilities. However, their low initial mechanical strength is still a major limita...Calcium phosphate cements have received much attention in recent decades owing to their biocompatibility, in situ handling, and shaping abilities. However, their low initial mechanical strength is still a major limitation. On the other hand, calcium aluminate cements (CACs) set fast and have a high initial strength and good corrosion resistance in contact with body fluids, making them excellent dental restorative materials. Therefore, the chemical, mechanical and biological properties of new-TCP/CA cement after aging in simulated body fluid (SBF) were investigated. The results indicated that the composites have setting times not appropriated for immediate applications and have degradation rates higher than those of the traditional CPCs. Moreover, the compressive strength of composite was lower than 5MPa and did not increase with SBF immersion. However, the α-TCP/CA composites showed a higher bioactivity at early stages and were not only more biocompatible but also more noncytotoxic.展开更多
Mining, ore processing, and smelting activities have contaminated soil and water resources with cyanide and heavy metals throughout the world. In-situ chemical immobilization is a remediation technology that decreases...Mining, ore processing, and smelting activities have contaminated soil and water resources with cyanide and heavy metals throughout the world. In-situ chemical immobilization is a remediation technology that decreases the concentrations of dissolved ions of copper cyanide and lead hydroxides by adsorption or precipitation. This study deals, with a process to recover lead hydroxides with natural hydroxyapatite powder and copper cyanide ions with sulphide precipitation from solutions of the cyanidation process. This technology is based on inducing nucleated precipitation of copper and silver in a serpentine reactor, using sodium sulfide as the precipitator, and sulfuric acid for pH control. Results show that pH value has a significant effect on copper cyanide removal efficiency, and it was determined the optimal pH range to be 2.5 - 3. At this pH value, the copper cyanide removal efficiency achieved was up to 99% with 60 percent of copper purity and the cyanide ions associated with this complex the recovery was 90%. For the elimination of lead hydroxides ions from the aqueous cyanidation process with natural hydroxiapatite powder the recovery was 99%. The abundance of cow bones, its low price and non-aggressive nature towards the environment are advantages for its utilization in point of view of wastewater cleanup and Dore with higher quality.展开更多
In this research,bone cement was prepared by mixing 2 g of magnesium hydroxyapatite(laboratory synthesized),12 g of polymethyl methacrylate,4 g of methyl methacrylate,and collagen(1,3,and 6 g).The samples were molded ...In this research,bone cement was prepared by mixing 2 g of magnesium hydroxyapatite(laboratory synthesized),12 g of polymethyl methacrylate,4 g of methyl methacrylate,and collagen(1,3,and 6 g).The samples were molded in a circular shape.They were inspected by visual microscopy,FTIR,XRD,and FESEM.They were engrossed in synthesized simulated body fluid for 1 month and then inspected by visual microscopy,FTIR,XRD,and FESEM.The samples prepared from 6 g of collagen showed the highest hydroxyapatite formation(high osseointegration)than the other samples.展开更多
基金supported by the Liaoning Province Doctoral Startup Foundation,China (No.20021054)the Liaoning Province Ministry Project of Education,China (No.202073425)
文摘Chitosan-hydroxyapatite （CS-HA） composite powders were synthesized via in situ co-precipitation method, through the reaction of Ca（NO3）2 and H3PO4 in the simulated body fluid （SBF） containing appropri- ate amount of chitosan. The thermal evolution, microstructure and morphology were studied by TG-DTA （thermogravimetry-differential thermal analysis）, XRD （X-ray diffraction）, FTIR （Fourier transform infrared spectroscopy） and TEM （transmission electron microscopy）. The in vitro bioactivity test showed that the obtained CS-HA composites had higher capability of inducing calcium ions deposition. Effects of CS-HA com- posites on the bioactivity and compressive strength of bioglass bone cement were investigated. The results indicated that the bioactivity of bioglass bone cement could be improved further when CS-HA composite pow- ders were added into the cement, and appropriate amount of CS-HA additive was favorable for compressive strength improvement of bioglass bone cement.
文摘To discuss the feasibility of bydroxyapatite bone cement （HAC） used as a drug delivery carrier and observe the bacteriostatic activity of HAC/ Norvancomycin（ HAC/ NVCM ） composite in vitro and its release characteristics in vivo. Bacteriostatic zone and cycle of composite containing 1.5wt% of NVCM were measured in vitro studies. In vivo stndies , the composite was implanted into the top of rabbit＇ s tibia as the local medication group, HAC without NVCM being composed was also implanted and NVCM was injected into auricular vein as the systemic medication group. Cnncentrations of NVCM in blood and local bone were measured in both groups at different time points. The experimental results showed that HAC did not influence the bacteriostatic activity of NVCM otviously, and NVCM exist in the porosities of HAC in the pattern of amorphism. The blood coueemrations of NVCM in local medication group were always lower than those in systemic medication group at any time point, while the bone concentrations of NVCM in local medication group were much higher than those of systemic medication group,which remained to be 3.96μg/mg/mL after 2 weeks. And HAC has good release characteristics as a drug delivery earricr.
基金Supported by Grant from the shaanxi Provincial Science and Technology Foundation(2000K_(14)-G_(16))
文摘Objective: To prepare hydroxyapatite cement (or calcium phosphate cement, CPC) and analyze its capability. Methods: Tetracalcium phosphate (TTCP) was prepared by the method of high heat. TTCP reacted with in simulated body situation and produced CPC, Its capability was analyzed by scanning electron microscopy (SEM) , X-ray diffraction(XRD). Its density, absorbing water coefficient, macroporosity and campressive strength were measured also. Results: The main element of CPC is hydroxyapatite (HA) , its microstructure comprised of needlelike or petal crystals. The diameter of micropore was 4-10 nm, density was 1.922 g/cm3, macroporosity was 29. 777% , absorbing coefficient was 15. 503%, compressive strength was 42. 70 Mpa. Conclusion: This CPC has three-dimensional spatial structure, its strength meets the need of cancellous bone grafting.
基金This work was partially supported by the National Natural Science Foundation of China(grant number 50272041)the Nanotechnology Special Foundation of Shanghai Science and Technology Committee(grant number 0144NM064).
文摘Glass based bone cement (GBC) was synthesized by mixing CaO-SiO2-P2O5 based glass powder with ammonium phosphate liquid medium. Bone-like hydroxyapatite (HAP, Ca10(PO4)6(OH)2) was found to form after GBC was immersed in simulated body fluid (SBF). HAP crystal grew with an increasing time along c axle and reached about 200 nm in length after 30 days, however, the end plane granularity remained 30-50 nm. The chemical composition, crystal structure and morphology of HAP formed from GBC were proved to have great resemblance with living HAP. It is believed that GBC was a desirabie biomedicai material with high bioactivity. Furthermore, the high compressive strength guaranteed the possibility of GBC in clinical application.
文摘Calcium phosphate cements have received much attention in recent decades owing to their biocompatibility, in situ handling, and shaping abilities. However, their low initial mechanical strength is still a major limitation. On the other hand, calcium aluminate cements (CACs) set fast and have a high initial strength and good corrosion resistance in contact with body fluids, making them excellent dental restorative materials. Therefore, the chemical, mechanical and biological properties of new-TCP/CA cement after aging in simulated body fluid (SBF) were investigated. The results indicated that the composites have setting times not appropriated for immediate applications and have degradation rates higher than those of the traditional CPCs. Moreover, the compressive strength of composite was lower than 5MPa and did not increase with SBF immersion. However, the α-TCP/CA composites showed a higher bioactivity at early stages and were not only more biocompatible but also more noncytotoxic.
文摘Mining, ore processing, and smelting activities have contaminated soil and water resources with cyanide and heavy metals throughout the world. In-situ chemical immobilization is a remediation technology that decreases the concentrations of dissolved ions of copper cyanide and lead hydroxides by adsorption or precipitation. This study deals, with a process to recover lead hydroxides with natural hydroxyapatite powder and copper cyanide ions with sulphide precipitation from solutions of the cyanidation process. This technology is based on inducing nucleated precipitation of copper and silver in a serpentine reactor, using sodium sulfide as the precipitator, and sulfuric acid for pH control. Results show that pH value has a significant effect on copper cyanide removal efficiency, and it was determined the optimal pH range to be 2.5 - 3. At this pH value, the copper cyanide removal efficiency achieved was up to 99% with 60 percent of copper purity and the cyanide ions associated with this complex the recovery was 90%. For the elimination of lead hydroxides ions from the aqueous cyanidation process with natural hydroxiapatite powder the recovery was 99%. The abundance of cow bones, its low price and non-aggressive nature towards the environment are advantages for its utilization in point of view of wastewater cleanup and Dore with higher quality.
文摘In this research,bone cement was prepared by mixing 2 g of magnesium hydroxyapatite(laboratory synthesized),12 g of polymethyl methacrylate,4 g of methyl methacrylate,and collagen(1,3,and 6 g).The samples were molded in a circular shape.They were inspected by visual microscopy,FTIR,XRD,and FESEM.They were engrossed in synthesized simulated body fluid for 1 month and then inspected by visual microscopy,FTIR,XRD,and FESEM.The samples prepared from 6 g of collagen showed the highest hydroxyapatite formation(high osseointegration)than the other samples.
