Preparation of porous Ti Al-based intermetallics with aligned and elongated pores by freeze-casting was investigated. Engineering Ti-43 Al-9V-1Y powder(D50=50 μm), carboxymethyl cellulose, and guar gum were used to p...Preparation of porous Ti Al-based intermetallics with aligned and elongated pores by freeze-casting was investigated. Engineering Ti-43 Al-9V-1Y powder(D50=50 μm), carboxymethyl cellulose, and guar gum were used to prepare the aqueous-based slurries for freeze-casting. Results showed that the porous Ti Al was obtained by using a freezing temperature of -5 ℃ and the pore structure was tailored by varying the particle content of slurry. The total porosity reduced from 81% to 62% and the aligned pore width dropped from approximately 500 to around 270 μm, with increasing the particle content from 10 to 30 vol.%. Furthermore, the compressive strength along the aligned pores increased from 16 to 120 MPa with the reduction of porosity. The effective thermal conductivities of porous Ti Al were lower than 1.81 W/(m·K) and showed anisotropic property with respect to the pore orientation.展开更多
A novel antibacterial biomimetic porous titanium implant with good osseointegration was prepared by freeze-casting and thermal oxidation.Bone integration properties of the porous titanium implant were evaluated by cel...A novel antibacterial biomimetic porous titanium implant with good osseointegration was prepared by freeze-casting and thermal oxidation.Bone integration properties of the porous titanium implant were evaluated by cell proliferation assay,alkaline phosphatase activity assay,X-ray examination and hard bone tissue biopsy.The in vitro cell proliferation and the level of differentiation of the group with a modified nano-porous implant surface were significantly higher than those in the group without surface modification and the dense titanium control group(P<0.05).In vivo,bone growth and osteogenesis were found in the experimental groups with modified and unmodified porous titanium implants;osteoblasts in the modified group had more mature differentiation in the pores compared to the unmodified group.Such implants can form solid,biologically compatible bone grafts with bone tissues,exhibiting good osseointegration.展开更多
This work aimed to prepare the nanospike surface-modified bionic porous titanium implants that feature favorableosteointegration performance and anti-bacterial functions.The implant was prepared using freeze casting,a...This work aimed to prepare the nanospike surface-modified bionic porous titanium implants that feature favorableosteointegration performance and anti-bacterial functions.The implant was prepared using freeze casting,and nanospikesurface-modification of the implant was performed using thermal oxidation.The pore morphology and size,mechanical properties,and osteogenic performance of the implants were analyzed and discussed.The results showed that when the volume ratio of titaniumpowder in slurry was set to be10%,the porosity,pore diameter,compressive strength,and elastic modulus of the porous sampleswere(58.32±1.08)%,(126.17±18.64)μm,(58.51±20.38)MPa and(1.70±0.52)GPa,respectively.When the porous sample wassintered at a temperature of1200°C for1h,these values were(58.24±1.50)%,(124.16±13.64)μm,(54.77±27.55)MPa and(1.63±0.30)GPa,respectively.The nanospike surface-modified bionic porous titanium implants had favorable pore morphology andsize,mechanical properties and osteointegration performance through technology optimization,and showed significant clinicalapplication prospect.展开更多
With the combination of surfactant and freeze-drying, we have developed two kinds of graphene spongy structures. On the one hand, using foams of soap bubbles as templates, three-dimensional porous graphene sponges wit...With the combination of surfactant and freeze-drying, we have developed two kinds of graphene spongy structures. On the one hand, using foams of soap bubbles as templates, three-dimensional porous graphene sponges with rich hierarchical pores have been synthesized. Pores of the material contain three levels of length scales, including millimeter, micrometer and nanometer. The structure can be tuned by changing the freezing media, adjusting the stirring rate or adding functional additives. On the other hand, by direct freeze-drying of a graphene oxide/surfactant suspension, a porous framework with directionally aligned pores is prepared. The surfactant gives a better dispersion of graphene oxide sheets, resulting in a high specific surface area. Both of the obtained materials exhibit excellent absorption capacity and good compression performance, providing a broad range of possible applications, such as absorbents, storage media, and carriers.展开更多
基金Projects(51775418,51375372)supported by the National Natural Science Foundation of China
文摘Preparation of porous Ti Al-based intermetallics with aligned and elongated pores by freeze-casting was investigated. Engineering Ti-43 Al-9V-1Y powder(D50=50 μm), carboxymethyl cellulose, and guar gum were used to prepare the aqueous-based slurries for freeze-casting. Results showed that the porous Ti Al was obtained by using a freezing temperature of -5 ℃ and the pore structure was tailored by varying the particle content of slurry. The total porosity reduced from 81% to 62% and the aligned pore width dropped from approximately 500 to around 270 μm, with increasing the particle content from 10 to 30 vol.%. Furthermore, the compressive strength along the aligned pores increased from 16 to 120 MPa with the reduction of porosity. The effective thermal conductivities of porous Ti Al were lower than 1.81 W/(m·K) and showed anisotropic property with respect to the pore orientation.
基金Projects (51290295,51305464) supported by the National Natural Science Foundation of ChinaProject (2016JJ6156) supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project (2016JC2064) supported by Key Research and Development Project of Hunan Province,ChinaProject (20130162120094) supported by Specialized Research Fund for the Doctoral Program of Higher Education,China
文摘A novel antibacterial biomimetic porous titanium implant with good osseointegration was prepared by freeze-casting and thermal oxidation.Bone integration properties of the porous titanium implant were evaluated by cell proliferation assay,alkaline phosphatase activity assay,X-ray examination and hard bone tissue biopsy.The in vitro cell proliferation and the level of differentiation of the group with a modified nano-porous implant surface were significantly higher than those in the group without surface modification and the dense titanium control group(P<0.05).In vivo,bone growth and osteogenesis were found in the experimental groups with modified and unmodified porous titanium implants;osteoblasts in the modified group had more mature differentiation in the pores compared to the unmodified group.Such implants can form solid,biologically compatible bone grafts with bone tissues,exhibiting good osseointegration.
基金Projects(51290295,51305464) supported by the National Natural Science Foundation of ChinaProject(2016JJ6156) supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(2016JC2064) supported by the Key Research and Development Program of Hunan Province,ChinaProject(20130162120094) supported by the Specialized Research Fund for the Doctoral Program of Higher Education,China
文摘This work aimed to prepare the nanospike surface-modified bionic porous titanium implants that feature favorableosteointegration performance and anti-bacterial functions.The implant was prepared using freeze casting,and nanospikesurface-modification of the implant was performed using thermal oxidation.The pore morphology and size,mechanical properties,and osteogenic performance of the implants were analyzed and discussed.The results showed that when the volume ratio of titaniumpowder in slurry was set to be10%,the porosity,pore diameter,compressive strength,and elastic modulus of the porous sampleswere(58.32±1.08)%,(126.17±18.64)μm,(58.51±20.38)MPa and(1.70±0.52)GPa,respectively.When the porous sample wassintered at a temperature of1200°C for1h,these values were(58.24±1.50)%,(124.16±13.64)μm,(54.77±27.55)MPa and(1.63±0.30)GPa,respectively.The nanospike surface-modified bionic porous titanium implants had favorable pore morphology andsize,mechanical properties and osteointegration performance through technology optimization,and showed significant clinicalapplication prospect.
基金This work is supported by Beijing Natural Science Foundation （No. 2122027）, the National Basic Research Program of China （No. 2011CB013000）, the National Natural Science Foundation of China （No. 51372133）, and the Tsinghua University Initiative Scientific Research Program （No. 2012Z02102）.
文摘With the combination of surfactant and freeze-drying, we have developed two kinds of graphene spongy structures. On the one hand, using foams of soap bubbles as templates, three-dimensional porous graphene sponges with rich hierarchical pores have been synthesized. Pores of the material contain three levels of length scales, including millimeter, micrometer and nanometer. The structure can be tuned by changing the freezing media, adjusting the stirring rate or adding functional additives. On the other hand, by direct freeze-drying of a graphene oxide/surfactant suspension, a porous framework with directionally aligned pores is prepared. The surfactant gives a better dispersion of graphene oxide sheets, resulting in a high specific surface area. Both of the obtained materials exhibit excellent absorption capacity and good compression performance, providing a broad range of possible applications, such as absorbents, storage media, and carriers.
