Additive manufacturing has received attention for the fabrication of medical implants that have customized and complicated structures.Biodegradable Zn metals are revolutionary materials for orthopedic implants.In this...Additive manufacturing has received attention for the fabrication of medical implants that have customized and complicated structures.Biodegradable Zn metals are revolutionary materials for orthopedic implants.In this study,pure Zn porous scaffolds with diamond structures were fabricated using customized laser powder bed fusion(L-PBF)technology.First,the mechanical properties,corrosion behavior,and biocompatibility of the pure Zn porous scaffolds were characterized in vitro.The scaffolds were then implanted into the rabbit femur critical-size bone defect model for 24 weeks.The results showed that the pure Zn porous scaffolds had compressive strength and rigidity comparable to those of cancellous bone,as well as relatively suitable degradation rates for bone regeneration.A benign host response was observed using hematoxylin and eosin(HE)staining of the heart,liver,spleen,lungs,and kidneys.Moreover,the pure Zn porous scaffold showed good biocompatibility and osteogenic promotion ability in vivo.This study showed that pure Zn porous scaffolds with customized structures fabricated using L-PBF represent a promising biodegradable solution for treating large bone defects.展开更多
Zn based metals have exhibited promising prospects as a structural material for biodegradable applications. Pure Zn porous scaffolds were produced by laser powder bed fusion(LPBF) based on data files of designing and ...Zn based metals have exhibited promising prospects as a structural material for biodegradable applications. Pure Zn porous scaffolds were produced by laser powder bed fusion(LPBF) based on data files of designing and CT scanning. Massive Zn evaporation during laser melting largely influenced the formation quality during LPBF of Zn metal. The metal vapor in processing chamber was blown off and suctioned out efficiently by an optimized gas circulation system. Numerical analysis was used to design and testify the performance of gas flow. The surface of scaffolds was covered with numerous particles in different sizes. Processing pores occurred near the outline contour of struts. The average grain size in width was8.5m, and the hardness was 43.8 HV. Chemical plus electrochemical polishing obtained uniform and smooth surface without processing pores, but the diameter of struts reduced to 250 αm from the design value 300 m. The poor surface quality and processing pores were resulted by the splashing particles included spatters and powders due to the recoil force of evaporation, and the horizontal movement of liquid metal due to overheating and wetting. The insufficient melting at the outline contour combined with good wetting of Zn liquid metal further increased the surface roughness and processing pores.展开更多
基金supported by the National Key R&D Program of China[grant number 2018YFE0104200]the National Natural Science Foundation of China[grant numbers 51901003,51931001,52171233,51875310]+1 种基金the Beijing Natural Science Foundation[grant number L212014]the Open Project of NMPA Key Laboratory for Dental Materials[grant number PKUSS20200401].
文摘Additive manufacturing has received attention for the fabrication of medical implants that have customized and complicated structures.Biodegradable Zn metals are revolutionary materials for orthopedic implants.In this study,pure Zn porous scaffolds with diamond structures were fabricated using customized laser powder bed fusion(L-PBF)technology.First,the mechanical properties,corrosion behavior,and biocompatibility of the pure Zn porous scaffolds were characterized in vitro.The scaffolds were then implanted into the rabbit femur critical-size bone defect model for 24 weeks.The results showed that the pure Zn porous scaffolds had compressive strength and rigidity comparable to those of cancellous bone,as well as relatively suitable degradation rates for bone regeneration.A benign host response was observed using hematoxylin and eosin(HE)staining of the heart,liver,spleen,lungs,and kidneys.Moreover,the pure Zn porous scaffold showed good biocompatibility and osteogenic promotion ability in vivo.This study showed that pure Zn porous scaffolds with customized structures fabricated using L-PBF represent a promising biodegradable solution for treating large bone defects.
基金supported by National Natural Science Foundation of China (51875310)National Key R&D Program of China (2017YFB1103300)
文摘Zn based metals have exhibited promising prospects as a structural material for biodegradable applications. Pure Zn porous scaffolds were produced by laser powder bed fusion(LPBF) based on data files of designing and CT scanning. Massive Zn evaporation during laser melting largely influenced the formation quality during LPBF of Zn metal. The metal vapor in processing chamber was blown off and suctioned out efficiently by an optimized gas circulation system. Numerical analysis was used to design and testify the performance of gas flow. The surface of scaffolds was covered with numerous particles in different sizes. Processing pores occurred near the outline contour of struts. The average grain size in width was8.5m, and the hardness was 43.8 HV. Chemical plus electrochemical polishing obtained uniform and smooth surface without processing pores, but the diameter of struts reduced to 250 αm from the design value 300 m. The poor surface quality and processing pores were resulted by the splashing particles included spatters and powders due to the recoil force of evaporation, and the horizontal movement of liquid metal due to overheating and wetting. The insufficient melting at the outline contour combined with good wetting of Zn liquid metal further increased the surface roughness and processing pores.
