Magnesium-based alloys are frequently reported as potential biodegradable orthopedic implant materials. Controlling the degradation rate and mechanical integrity of magnesium alloys in the physiological environment is...Magnesium-based alloys are frequently reported as potential biodegradable orthopedic implant materials. Controlling the degradation rate and mechanical integrity of magnesium alloys in the physiological environment is the key to their applications. In this study, calcium phosphate （Ca-P） coating was prepared on AZ60 magnesium alloy using phosphating technology. AZ60 samples were immersed in a phosphating solution at 37 ± 2 ℃ for 30 min, and the solution pH was adjusted to 2.6 to 2.8 by adding NaOH solution. Then, the samples were dried in an attemperator at 60 ℃. The degradation behavior was studied in vivo using Ca-P coated and uncoated magnesium alloys. Samples of these two different materials were implanted into rabbit femora, and the corrosion resistances were evaluated after 1, 2, and 3 months. The Ca-P coated samples corroded slower than the uncoated samples with prolonged time. Significant differences （p 〈 0.05） in mass losses and corrosion rates between uncoated samples and Ca-P coated samples were observed by micro-computed tomography. The results indicate that the Ca-P coating could slow down the degradation of magnesium alloy in vivo.展开更多
Calcium-phosphate compounds（Ca-P） coating was prepared on an Mg-A1 alloy（AZ60）. Biodegradation of Ca-P coated magnesium alloy was evaluated in simulated body fluid（SBF） by examining the changes in magnesium ion ...Calcium-phosphate compounds（Ca-P） coating was prepared on an Mg-A1 alloy（AZ60）. Biodegradation of Ca-P coated magnesium alloy was evaluated in simulated body fluid（SBF） by examining the changes in magnesium ion concentration and pH value, which indicated that the Ca-P coating on magnesium alloy strongly affected the cor- rosion of magnesium alloy. Osteoblast MC3T3-E1 cells were utilized to investigate the cellular eytocompatibility. The cytocompatibility was measured by carrying out a series of tests, such as cholecystokinin-octapeptide（CCK-8） test, alkaline phosphatase activity（ALP） test, cellular morphology of hematoxylin-eosin（HE） staining and the induc- tion of apoptosis. It was found that the cell function showed better in the Ca-P coated Mg-alloy extract than in the uncoated magnesium alloy extract. In summary, the results indicate that the Ca-P coating can improve the corrosion resistance of magnesium alloy and elevate cellular proliferation and differentiation of osteoblast MC3T3-E1 cells.展开更多
Magnesium alloys are potentially attractive biodegradable materials.However,their rapid corrosion rate limits their biomedical application.To slow down the rate of biodegradation,a protective calcium-phosphate coating...Magnesium alloys are potentially attractive biodegradable materials.However,their rapid corrosion rate limits their biomedical application.To slow down the rate of biodegradation,a protective calcium-phosphate coating was formed on a magnesium alloy substrate by a hydrothermal method.Scanning electron microscope results showed that the coating consisted of two layers with different crystalline characteristics.The loose outer layer showed a prism-like crystal structure,while the compact inner layer is a dense ultra-fine regular di-pyramid-like structure with an average grain dimension of ～200 nm.The compositions of the inner layer and outer layer were calcium-deficient hydroxyapatite (Ca-def HA) and dicalcium phosphate (DCPa),respectively.The coating adhered well to the substrate with a thickness of about 15 m.Immersion in Hank's solution indicated that the coating could significantly improve the degradation properties of magnesium alloy.The pH of the solution containing the coated samples increased much more slowly than the untreated control.After 8 d immersion,the uncoated sample had corroded seriously while the coated sample was much less corroded.The Ca/P atom ratio in both the layers of the coating increased and the coating was still protecting the substrate.The two layers of the coating corroded differently because of differences in solubility.The outer layer was more severely attacked and many holes were formed on the surface,the inner layer suffered less attack.In addition,a growth of precipitate on the inner layer was observed,indicating that surface bioactivity was improved by the coating.Thus,magnesium alloys coated with a Ca-P coating prepared by a hydrothermal method are promising candidate biodegradable biomaterials,and further investigation of in vivo degradation behavior is suggested.展开更多
To improve the anti-corrosion behaviors of magnesium alloy in the inner environment of human body,a bioactive Ca-P coating was deposited on the AZ60 magnesium alloy by a novel simple method.The morphologies of the Ca-...To improve the anti-corrosion behaviors of magnesium alloy in the inner environment of human body,a bioactive Ca-P coating was deposited on the AZ60 magnesium alloy by a novel simple method.The morphologies of the Ca-P coatings formed under different treatment time were studied by scanning electron microscopy（SEM）.The corrosion behaviors of Ca-P coating were investigated by electrochemical polarization test and electrochemical impedance spectroscopy in both 3％（mass fraction） NaCl solution and simulated body fluid（SBF）.Immersion test in SBF was performed to evaluate the corrosion rate of Ca-P coated magnesium alloy.X-Ray diffraction（XRD） analysis result shows that the coating mentioned above mainly consists of dicalcium phosphate dehydrate（CaHPO4·2H2O,DCPD） and β-tricalcium phosphate dehydrate[β-TCP,Ca3（PO4）2],which exhibits good corrosion resistance.After magnesium alloy was immersed in 1 mol/L NaOH solution at 80 ℃ for 2 h,hydroxyapatite [Ca10（PO4）6（OH）2,HA]appeared on the magnesium alloy substrate,which can further decrease the corrosion rate of AZ60 magnesium alloy in SBF.展开更多
A hydrothermal deposition method was utilized to fabricate Ca-P composite coating induced by the layer-by-layer(LbL)assembled polyvinylpyrrolidone/deoxyribonucleic acid(PVP/DNA)_(20) multilayer on AZ31 alloy.The surfa...A hydrothermal deposition method was utilized to fabricate Ca-P composite coating induced by the layer-by-layer(LbL)assembled polyvinylpyrrolidone/deoxyribonucleic acid(PVP/DNA)_(20) multilayer on AZ31 alloy.The surface morphology and compositions were characterized by SEM,EDS,FTIR and XRD.Besides,the corrosion resistance and degradation behavior of the coating were tested via electrochemical polarization,impedance spectroscopy and immersion measurements.Results show that the main components of Ca-P coatings are hydroxyapatite,Ca_(3)(PO_(4))_(2) and Mg_(3)(PO_(4))_(2)·nH_(2)O.The LbL-assembled DNA and PVP promote the adsorption of Ca-P deposits on the sample surface,and structures and functional groups of the polyelectrolyte in the outermost layer are the primary influencing factor for the induction of the Ca-P coating.Carboxyl groups have the best biomineralization effect among all related functional groups.The enhanced corrosion resistance and adhesion highlight a promising use of(PVP/DNA)_(20)-induced Ca-P coatings in the field of biomedical magnesium alloys.展开更多
The burst release of Zn 2+from the naked pure Zn and Zn-based alloys could induce local and sys-temic toxicity,which limits their clinical applications as biodegradable implants.In order to inhibit the explosive relea...The burst release of Zn 2+from the naked pure Zn and Zn-based alloys could induce local and sys-temic toxicity,which limits their clinical applications as biodegradable implants.In order to inhibit the explosive release of zinc ions,a protective Ca-P coating was synthesized on biodegradable Zn al-loy.The microstructure,corrosion resistance,antibacterial activity,and biosafety of the Ca-P coating are systematically investigated.Electrochemical tests revealed that Ca-P protective layer has enhanced the anti-corrosion behavior of Zn alloy.Furthermore,Ca-P protective layer showed good biocompatibility,as demonstrated by significantly increased cell viability,good attachment,and spreading at a higher cell density.Besides,the Ca-P coating could also retain the antibacterial ability and inhibit the bacterial ad-hesion.The Ca-P protective layer synthesized on biodegradable Zn alloy can be considered and applied in future biomedical applications.展开更多
基金Acknowledgment This work is supported by the National Natural Science Foundation of China （No.31070841）.
文摘Magnesium-based alloys are frequently reported as potential biodegradable orthopedic implant materials. Controlling the degradation rate and mechanical integrity of magnesium alloys in the physiological environment is the key to their applications. In this study, calcium phosphate （Ca-P） coating was prepared on AZ60 magnesium alloy using phosphating technology. AZ60 samples were immersed in a phosphating solution at 37 ± 2 ℃ for 30 min, and the solution pH was adjusted to 2.6 to 2.8 by adding NaOH solution. Then, the samples were dried in an attemperator at 60 ℃. The degradation behavior was studied in vivo using Ca-P coated and uncoated magnesium alloys. Samples of these two different materials were implanted into rabbit femora, and the corrosion resistances were evaluated after 1, 2, and 3 months. The Ca-P coated samples corroded slower than the uncoated samples with prolonged time. Significant differences （p 〈 0.05） in mass losses and corrosion rates between uncoated samples and Ca-P coated samples were observed by micro-computed tomography. The results indicate that the Ca-P coating could slow down the degradation of magnesium alloy in vivo.
基金Supported by the National Natural Science Foundation of China（No.31070841）.
文摘Calcium-phosphate compounds（Ca-P） coating was prepared on an Mg-A1 alloy（AZ60）. Biodegradation of Ca-P coated magnesium alloy was evaluated in simulated body fluid（SBF） by examining the changes in magnesium ion concentration and pH value, which indicated that the Ca-P coating on magnesium alloy strongly affected the cor- rosion of magnesium alloy. Osteoblast MC3T3-E1 cells were utilized to investigate the cellular eytocompatibility. The cytocompatibility was measured by carrying out a series of tests, such as cholecystokinin-octapeptide（CCK-8） test, alkaline phosphatase activity（ALP） test, cellular morphology of hematoxylin-eosin（HE） staining and the induc- tion of apoptosis. It was found that the cell function showed better in the Ca-P coated Mg-alloy extract than in the uncoated magnesium alloy extract. In summary, the results indicate that the Ca-P coating can improve the corrosion resistance of magnesium alloy and elevate cellular proliferation and differentiation of osteoblast MC3T3-E1 cells.
基金supported by the Program for Young Excellent Talents in Tongji University(2009KJ003)"Chen Guang"Project(10CG21)from the Shanghai Municipal Education CommissionShanghai Education Development Foundation
文摘Magnesium alloys are potentially attractive biodegradable materials.However,their rapid corrosion rate limits their biomedical application.To slow down the rate of biodegradation,a protective calcium-phosphate coating was formed on a magnesium alloy substrate by a hydrothermal method.Scanning electron microscope results showed that the coating consisted of two layers with different crystalline characteristics.The loose outer layer showed a prism-like crystal structure,while the compact inner layer is a dense ultra-fine regular di-pyramid-like structure with an average grain dimension of ～200 nm.The compositions of the inner layer and outer layer were calcium-deficient hydroxyapatite (Ca-def HA) and dicalcium phosphate (DCPa),respectively.The coating adhered well to the substrate with a thickness of about 15 m.Immersion in Hank's solution indicated that the coating could significantly improve the degradation properties of magnesium alloy.The pH of the solution containing the coated samples increased much more slowly than the untreated control.After 8 d immersion,the uncoated sample had corroded seriously while the coated sample was much less corroded.The Ca/P atom ratio in both the layers of the coating increased and the coating was still protecting the substrate.The two layers of the coating corroded differently because of differences in solubility.The outer layer was more severely attacked and many holes were formed on the surface,the inner layer suffered less attack.In addition,a growth of precipitate on the inner layer was observed,indicating that surface bioactivity was improved by the coating.Thus,magnesium alloys coated with a Ca-P coating prepared by a hydrothermal method are promising candidate biodegradable biomaterials,and further investigation of in vivo degradation behavior is suggested.
基金Supported by the National Natural Science Foundation of China（No.31070841）, the National Key Basic Research and Development Program of China（No.2010CB631001） and the Science ＆ Technology Pillar Program of Changchun City, China （No. 11KZ30）.
文摘To improve the anti-corrosion behaviors of magnesium alloy in the inner environment of human body,a bioactive Ca-P coating was deposited on the AZ60 magnesium alloy by a novel simple method.The morphologies of the Ca-P coatings formed under different treatment time were studied by scanning electron microscopy（SEM）.The corrosion behaviors of Ca-P coating were investigated by electrochemical polarization test and electrochemical impedance spectroscopy in both 3％（mass fraction） NaCl solution and simulated body fluid（SBF）.Immersion test in SBF was performed to evaluate the corrosion rate of Ca-P coated magnesium alloy.X-Ray diffraction（XRD） analysis result shows that the coating mentioned above mainly consists of dicalcium phosphate dehydrate（CaHPO4·2H2O,DCPD） and β-tricalcium phosphate dehydrate[β-TCP,Ca3（PO4）2],which exhibits good corrosion resistance.After magnesium alloy was immersed in 1 mol/L NaOH solution at 80 ℃ for 2 h,hydroxyapatite [Ca10（PO4）6（OH）2,HA]appeared on the magnesium alloy substrate,which can further decrease the corrosion rate of AZ60 magnesium alloy in SBF.
基金This work was supported by the National Natural Science Foundation of China(Grant No.52071191)the Natural Science Foundation of Shandong Province(ZR2020QE009)+1 种基金the Research Start-up Fund of Shandong University of Science and Technology(01040125219)the“Elite Plan”Foundation of Shandong University of Science and Technology(0104060541112).
文摘A hydrothermal deposition method was utilized to fabricate Ca-P composite coating induced by the layer-by-layer(LbL)assembled polyvinylpyrrolidone/deoxyribonucleic acid(PVP/DNA)_(20) multilayer on AZ31 alloy.The surface morphology and compositions were characterized by SEM,EDS,FTIR and XRD.Besides,the corrosion resistance and degradation behavior of the coating were tested via electrochemical polarization,impedance spectroscopy and immersion measurements.Results show that the main components of Ca-P coatings are hydroxyapatite,Ca_(3)(PO_(4))_(2) and Mg_(3)(PO_(4))_(2)·nH_(2)O.The LbL-assembled DNA and PVP promote the adsorption of Ca-P deposits on the sample surface,and structures and functional groups of the polyelectrolyte in the outermost layer are the primary influencing factor for the induction of the Ca-P coating.Carboxyl groups have the best biomineralization effect among all related functional groups.The enhanced corrosion resistance and adhesion highlight a promising use of(PVP/DNA)_(20)-induced Ca-P coatings in the field of biomedical magnesium alloys.
基金supported by the National Natural Science Foundation of China(No.31700819)the Young Elite Scientists Sponsorship Program by CAST(YESS,No.2018QNRC001).
文摘The burst release of Zn 2+from the naked pure Zn and Zn-based alloys could induce local and sys-temic toxicity,which limits their clinical applications as biodegradable implants.In order to inhibit the explosive release of zinc ions,a protective Ca-P coating was synthesized on biodegradable Zn al-loy.The microstructure,corrosion resistance,antibacterial activity,and biosafety of the Ca-P coating are systematically investigated.Electrochemical tests revealed that Ca-P protective layer has enhanced the anti-corrosion behavior of Zn alloy.Furthermore,Ca-P protective layer showed good biocompatibility,as demonstrated by significantly increased cell viability,good attachment,and spreading at a higher cell density.Besides,the Ca-P coating could also retain the antibacterial ability and inhibit the bacterial ad-hesion.The Ca-P protective layer synthesized on biodegradable Zn alloy can be considered and applied in future biomedical applications.
