Biomedical implants and devices for tissue engineering in clinics,mainly made of polymers and stiff metallic materials,require possibly secondary surgery or life-long medicine.Biodegradable metals for biomedical impla...Biomedical implants and devices for tissue engineering in clinics,mainly made of polymers and stiff metallic materials,require possibly secondary surgery or life-long medicine.Biodegradable metals for biomedical implants and devices exhibit huge potential to improve the prognosis of patients.In this work,we developed a new type of biodegradable binary zinc(Zn)alloys with 16 rare earth elements(REEs)including Sc,Y,La to Nd,and Sm to Lu,respectively.The effects of REEs on the alloy microstructure,mechanical properties,corrosion behavior and in vitro and in vivo biocompatibility of Zn were systematically investigated using pure Zn as control.All Zn-RE alloys generally exhibited improved mechanical properties,and biocompatibilities compared to pure Zn,especially the tensile strength and ductility of Zn-RE alloys were dramatically enhanced.Among the Zn-RE alloys,different REEs presented enhancement effects at varied extent.Y,Ho and Lu were the three elements displaying greatest improvements in majority of alloys properties,while Eu,Gd and Dy exhibited least improvement.Furthermore,the Zn-RE alloys were comparable with other Zn alloys and also exhibited superior properties to Mg-RE alloys.The in vivo experiment using Zn-La,Zn-Ce,and Zn-Nd alloys as tibia bone implants in rabbit demonstrated the excellent tissue biocompatibility and much more obvious osseointegration than the pure Zn control group.This work presented the significant potential of the developed Zn-RE binary alloys as novel degradable metal for biomedical implants and devices.展开更多
The microstructure of the as-cast Mg 44 Zn 44 Gd 12 alloy was investigated by using X-ray diffraction（XRD）,differentical scanning（DSC）,scanning electron microscopy（SEM） and a detailed transmission electron micro...The microstructure of the as-cast Mg 44 Zn 44 Gd 12 alloy was investigated by using X-ray diffraction（XRD）,differentical scanning（DSC）,scanning electron microscopy（SEM） and a detailed transmission electron microscope.The XRD,DSC and SEM results indicated that the as-cast Mg 44 Zn 44 Gd 12 alloy were mainly composed of three types of phases：the primary solidification phase,the dendritic phase and the eutectic phase.The primary solidification phase had an icosahedral structure.The dendritic phase was the W-phase,and eutectic structure phase was the Mg 7 Zn 3 phase.Microstructures of icosahedral phase（I-phase）,W-phase and Mg 7 Zn 3 phase in Mg 44 Zn 44 Gd 12 alloy were investigated.The results indicated that the I-phase in Mg 44 Zn 44 Gd 12 alloy was a face-centered icosahedral quasicrystal with stoichiometric composition of Mg 42 Zn 50 Gd 8 which had an excellent thermal stability up to 420 °C.The solid solution of the Gd gradually decreased during solidification,which played an important role in activating the formation of Mg 7 Zn 3 phase and W-phase from icosahedral phases.展开更多
基金supported by the National Key R&D Program of China[2018YFE0104200]the National Natural Science Foundation of China[51931001,52171233,52271243,U22A20121]+2 种基金the INTERNATIONAL COOPERATION and Exchange project of NSFC-RFBR[52111530042]the Beijing Natural Science Foundation[L212014]the Beijing Nova Program.
文摘Biomedical implants and devices for tissue engineering in clinics,mainly made of polymers and stiff metallic materials,require possibly secondary surgery or life-long medicine.Biodegradable metals for biomedical implants and devices exhibit huge potential to improve the prognosis of patients.In this work,we developed a new type of biodegradable binary zinc(Zn)alloys with 16 rare earth elements(REEs)including Sc,Y,La to Nd,and Sm to Lu,respectively.The effects of REEs on the alloy microstructure,mechanical properties,corrosion behavior and in vitro and in vivo biocompatibility of Zn were systematically investigated using pure Zn as control.All Zn-RE alloys generally exhibited improved mechanical properties,and biocompatibilities compared to pure Zn,especially the tensile strength and ductility of Zn-RE alloys were dramatically enhanced.Among the Zn-RE alloys,different REEs presented enhancement effects at varied extent.Y,Ho and Lu were the three elements displaying greatest improvements in majority of alloys properties,while Eu,Gd and Dy exhibited least improvement.Furthermore,the Zn-RE alloys were comparable with other Zn alloys and also exhibited superior properties to Mg-RE alloys.The in vivo experiment using Zn-La,Zn-Ce,and Zn-Nd alloys as tibia bone implants in rabbit demonstrated the excellent tissue biocompatibility and much more obvious osseointegration than the pure Zn control group.This work presented the significant potential of the developed Zn-RE binary alloys as novel degradable metal for biomedical implants and devices.
基金supported by National Key Basic Research Program (2007CB613706)the National Science and Technology Supporting Plan of the Twelfth Five-year (2011BAE22B04-2)the project of Innovation Project for Talents (PHR200906101)
文摘The microstructure of the as-cast Mg 44 Zn 44 Gd 12 alloy was investigated by using X-ray diffraction（XRD）,differentical scanning（DSC）,scanning electron microscopy（SEM） and a detailed transmission electron microscope.The XRD,DSC and SEM results indicated that the as-cast Mg 44 Zn 44 Gd 12 alloy were mainly composed of three types of phases：the primary solidification phase,the dendritic phase and the eutectic phase.The primary solidification phase had an icosahedral structure.The dendritic phase was the W-phase,and eutectic structure phase was the Mg 7 Zn 3 phase.Microstructures of icosahedral phase（I-phase）,W-phase and Mg 7 Zn 3 phase in Mg 44 Zn 44 Gd 12 alloy were investigated.The results indicated that the I-phase in Mg 44 Zn 44 Gd 12 alloy was a face-centered icosahedral quasicrystal with stoichiometric composition of Mg 42 Zn 50 Gd 8 which had an excellent thermal stability up to 420 °C.The solid solution of the Gd gradually decreased during solidification,which played an important role in activating the formation of Mg 7 Zn 3 phase and W-phase from icosahedral phases.
