Micro-arc oxidation （MAO） is an enhanced chemical technology in an electrolyte medium to obtain coating structures on valve-metal surfaces. Titanium oxide films obtained by MAO in the sodium phosphate electrolyte we...Micro-arc oxidation （MAO） is an enhanced chemical technology in an electrolyte medium to obtain coating structures on valve-metal surfaces. Titanium oxide films obtained by MAO in the sodium phosphate electrolyte were investigated. The films were composed mainly of TiO2 phases in the form of anatase and mille and enriched with Na and P elements at the surface. Their apafite-inducing ability was evaluated in a simulated body fluid （SBF）. When immersing in SBF for over 30 d, a preferential carbonated-hydroxyapatite was formed on the surfaces of the films, which suggests that the MAO-treated titanium has a promising positive biological response.展开更多
A novel, Ti-6 Al-4 V(Ti64)/Hydroxyapatite(HA at 5% by weight concentration) metal/ceramic composite has been fabricated using electron beam powder bed fusion(EPBF) additive manufacturing(AM): specifically, the commerc...A novel, Ti-6 Al-4 V(Ti64)/Hydroxyapatite(HA at 5% by weight concentration) metal/ceramic composite has been fabricated using electron beam powder bed fusion(EPBF) additive manufacturing(AM): specifically, the commercial electron beam melting(EBM?) process. In addition to solid Ti64 and Ti64/5% HA samples, four different unit cell(model) open-cellular mesh structures for the Ti64/5% HA composite were fabricated having densities ranging from 0.68 to 1.12 g/cm^3, and corresponding Young's moduli ranging from 2.9 to 8.0 GPa, and compressive strengths ranging from ~3 to 11 MPa. The solid Ti64/5%HA composite exhibited an optimal tensile strength of 123 MPa, and elongation of 5.5% in contrast to a maximum compressive strength of 875 MPa. Both the solid composite and mesh samples deformed primarily by brittle deformation, with the mesh samples exhibiting erratic, brittle crushing. Solid, EPBF-fabricated Ti64 samples had a Vickers microindentation hardness of 4.1 GPa while the Ti64/5%HA solid composite exhibited a Vickers microindentation hardness of 6.8 GPa. The lowest density Ti64/5%HA composite mesh strut sections had a Vickers microindentation hardness of 7.1 GPa. Optical metallography(OM) and scanning electron microscopy(SEM) analysis showed the HA dispersoids to be highly segregated along domain or grain boundaries, but homogeneously distributed along alpha(hcp) platelet boundaries within these domains in the Ti64 matrix for both the solid and mesh composites. The alpha platelet width varied from ~5 μm in the EPBF-fabricated Ti64 to ~1.1 m for the Ti64/5%HA mesh strut. The precursor HA powder diameter averaged 5 μm, in contrast to the dispersed HA particle diameters in the Ti64/5%HA composite which averaged 0.5 m. This work highlights the use of EPBF AM as a novel process for fabrication of a true composite structure, consisting of a Ti64 matrix and interspersed and exposed HA domains, which to the authors' knowledge has not been reported before. The results also illustrate the prospects not only for fabricating 展开更多
Dengue virus type 2 ThNH7/93 retained infectious activity after purification by ceramic hydroxyapatite chromatogra-phy. Dengue virus type 2 culture fluid was loaded onto the ceramic hydroxyapatite column and eluted wi...Dengue virus type 2 ThNH7/93 retained infectious activity after purification by ceramic hydroxyapatite chromatogra-phy. Dengue virus type 2 culture fluid was loaded onto the ceramic hydroxyapatite column and eluted with a linear gradient of sodium phosphate buffer. Culture fluid and protein contaminants derived from host cells were eluted initially, followed by elutions of dsDNA, and then dengue virus type 2. The recoveries of dengue virus type 2 were 64 ± 14% (n = 11) in the hemagglutination (HA) test and 60% (n = 2) determined by focus assay for viral infectivity. This protocol was highly reproducible, simple, rapid, and appears applicable to other virus species such as influenza virus, Japanese encephalitis virus and adenovirus.展开更多
目的研究陶瓷羟基磷灰石(ceramic hydroxyapatite,CHT)I型和II型对2种单克隆抗体(monoclonal Ab,m Ab)1和2聚集体的去除工艺。方法层析仪为AKTA AVANT 150,层析柱为Tricon 10/50,先进行CHT I、CHT II 2种填料的动态载样量研究,然后选取...目的研究陶瓷羟基磷灰石(ceramic hydroxyapatite,CHT)I型和II型对2种单克隆抗体(monoclonal Ab,m Ab)1和2聚集体的去除工艺。方法层析仪为AKTA AVANT 150,层析柱为Tricon 10/50,先进行CHT I、CHT II 2种填料的动态载样量研究,然后选取合适的载量进行分离纯化研究。上样条件为5 mmol/L磷酸二氢钠(Na H2PO4),p H 6.5,上样,然后用10 mmol/L Na H2PO4,p H6.5和10 mmol/L Na H2PO4,2 mol/L Na Cl,p H 6.5梯度洗脱来分离单体和聚集体。用分子尺寸排阻高效液相色谱(SEC-HPLC)测定上样蛋白溶液和洗脱峰单体及聚集体的含量。使用20 cm高的XK 16/40的层析柱进行工艺放大研究。结果 m Ab 1在CHT I型的载量为40 mg/m L,去除后单体含量为98.6%,工艺收率为92.5%;m Ab 2在CHT I型的载量为45 mg/m L,去除后单体含量为98.8%,工艺收率为91.5%;m Ab 1在CHT II型载量为16 mg/m L,去除后单体含量为99.8%,工艺收率为91.8%;m Ab 2在CHT II型载量为20 mg/m L,去除后单体含量为99.9%,工艺回收率为92.2%。结论 2种类型的陶瓷羟基磷灰石填料在聚集体含量高于10%的情况下,都有很好的去除能力,去除结果符合法规要求。该方法操作简单,能够很顺利的进行工艺放大,满足中试和生产需求。展开更多
Dense hydroxyapatite （HA） ceramic is a promising material for hard tissue repair due to its unique physical properties and biologic properties. However, the brittleness and low compressive strength of traditional HA...Dense hydroxyapatite （HA） ceramic is a promising material for hard tissue repair due to its unique physical properties and biologic properties. However, the brittleness and low compressive strength of traditional HA ceramics limited their applications, because previous sintering methods produced HA ceramics with crystal sizes greater than nanometer range. In this study, nano-sized HA powder was employed to fabricate dense nanocrystal HA ceramic by high pressure molding, and followed by a three-step sintering process. The phase composition, microstructure, crystal dimension and crystal shape of the sintered ceramic were examined by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. Mechanical properties of the HA ceramic were tested, and cytocompatibility was evaluated. The phase of the sintered ceramic was pure HA, and the crystal size was about 200 nm. The compressive strength and elastic modulus of the HA ceramic were comparable to human cortical bone, especially the good fatigue strength overcame brittleness of traditional sintered HA ceramics. Cell attachment experiment also demonstrated that the ceramics had a good cytocompatibility.展开更多
基金This work is financially supported by the National Natural Science Foundation of China (Nos. 50572029 and 50272021)the Natural Science Foundation of Guangdong Province, China (No. 0425786).
文摘Micro-arc oxidation （MAO） is an enhanced chemical technology in an electrolyte medium to obtain coating structures on valve-metal surfaces. Titanium oxide films obtained by MAO in the sodium phosphate electrolyte were investigated. The films were composed mainly of TiO2 phases in the form of anatase and mille and enriched with Na and P elements at the surface. Their apafite-inducing ability was evaluated in a simulated body fluid （SBF）. When immersing in SBF for over 30 d, a preferential carbonated-hydroxyapatite was formed on the surfaces of the films, which suggests that the MAO-treated titanium has a promising positive biological response.
文摘A novel, Ti-6 Al-4 V(Ti64)/Hydroxyapatite(HA at 5% by weight concentration) metal/ceramic composite has been fabricated using electron beam powder bed fusion(EPBF) additive manufacturing(AM): specifically, the commercial electron beam melting(EBM?) process. In addition to solid Ti64 and Ti64/5% HA samples, four different unit cell(model) open-cellular mesh structures for the Ti64/5% HA composite were fabricated having densities ranging from 0.68 to 1.12 g/cm^3, and corresponding Young's moduli ranging from 2.9 to 8.0 GPa, and compressive strengths ranging from ~3 to 11 MPa. The solid Ti64/5%HA composite exhibited an optimal tensile strength of 123 MPa, and elongation of 5.5% in contrast to a maximum compressive strength of 875 MPa. Both the solid composite and mesh samples deformed primarily by brittle deformation, with the mesh samples exhibiting erratic, brittle crushing. Solid, EPBF-fabricated Ti64 samples had a Vickers microindentation hardness of 4.1 GPa while the Ti64/5%HA solid composite exhibited a Vickers microindentation hardness of 6.8 GPa. The lowest density Ti64/5%HA composite mesh strut sections had a Vickers microindentation hardness of 7.1 GPa. Optical metallography(OM) and scanning electron microscopy(SEM) analysis showed the HA dispersoids to be highly segregated along domain or grain boundaries, but homogeneously distributed along alpha(hcp) platelet boundaries within these domains in the Ti64 matrix for both the solid and mesh composites. The alpha platelet width varied from ~5 μm in the EPBF-fabricated Ti64 to ~1.1 m for the Ti64/5%HA mesh strut. The precursor HA powder diameter averaged 5 μm, in contrast to the dispersed HA particle diameters in the Ti64/5%HA composite which averaged 0.5 m. This work highlights the use of EPBF AM as a novel process for fabrication of a true composite structure, consisting of a Ti64 matrix and interspersed and exposed HA domains, which to the authors' knowledge has not been reported before. The results also illustrate the prospects not only for fabricating
文摘目的用填料为羟基磷灰石的层析柱纯化抗TNF-α单克隆抗体。方法经protein A为填料的层析柱纯化抗TNF-α单克隆抗体后,通过Do E实验设计,对填料为羟基磷灰石的层析柱的洗脱流速、p H值及盐浓度进行优化,确定最佳洗脱条件后,进行抗TNF-α单克隆抗体的纯化,纯化产物经HPLC及毛细管电泳法检测其浓度、多聚体含量及纯度。结果抗TNF-α单克隆抗体经protein A层析纯化后,回收率达96.1%,纯度为96.0%,多聚体含量下降至1.9%。通过Do E优化,筛选出最佳条件范围为：流速1-3 ml/min,0.25-0.30 mol/L Na Cl,p H 7.0-7.3,选定1 ml/min流速、0.25 mol/L Na Cl、p H 7.0、作为洗脱条件进行纯化,回收率为93.1%,纯度为97.3%,多聚体含量为0,优于参比制剂。结论将羟基磷灰石用于抗TNF-α单克隆抗体的中度纯化,获得符合参比制剂质量的产品。
文摘Dengue virus type 2 ThNH7/93 retained infectious activity after purification by ceramic hydroxyapatite chromatogra-phy. Dengue virus type 2 culture fluid was loaded onto the ceramic hydroxyapatite column and eluted with a linear gradient of sodium phosphate buffer. Culture fluid and protein contaminants derived from host cells were eluted initially, followed by elutions of dsDNA, and then dengue virus type 2. The recoveries of dengue virus type 2 were 64 ± 14% (n = 11) in the hemagglutination (HA) test and 60% (n = 2) determined by focus assay for viral infectivity. This protocol was highly reproducible, simple, rapid, and appears applicable to other virus species such as influenza virus, Japanese encephalitis virus and adenovirus.
文摘目的研究陶瓷羟基磷灰石(ceramic hydroxyapatite,CHT)I型和II型对2种单克隆抗体(monoclonal Ab,m Ab)1和2聚集体的去除工艺。方法层析仪为AKTA AVANT 150,层析柱为Tricon 10/50,先进行CHT I、CHT II 2种填料的动态载样量研究,然后选取合适的载量进行分离纯化研究。上样条件为5 mmol/L磷酸二氢钠(Na H2PO4),p H 6.5,上样,然后用10 mmol/L Na H2PO4,p H6.5和10 mmol/L Na H2PO4,2 mol/L Na Cl,p H 6.5梯度洗脱来分离单体和聚集体。用分子尺寸排阻高效液相色谱(SEC-HPLC)测定上样蛋白溶液和洗脱峰单体及聚集体的含量。使用20 cm高的XK 16/40的层析柱进行工艺放大研究。结果 m Ab 1在CHT I型的载量为40 mg/m L,去除后单体含量为98.6%,工艺收率为92.5%;m Ab 2在CHT I型的载量为45 mg/m L,去除后单体含量为98.8%,工艺收率为91.5%;m Ab 1在CHT II型载量为16 mg/m L,去除后单体含量为99.8%,工艺收率为91.8%;m Ab 2在CHT II型载量为20 mg/m L,去除后单体含量为99.9%,工艺回收率为92.2%。结论 2种类型的陶瓷羟基磷灰石填料在聚集体含量高于10%的情况下,都有很好的去除能力,去除结果符合法规要求。该方法操作简单,能够很顺利的进行工艺放大,满足中试和生产需求。
文摘Dense hydroxyapatite （HA） ceramic is a promising material for hard tissue repair due to its unique physical properties and biologic properties. However, the brittleness and low compressive strength of traditional HA ceramics limited their applications, because previous sintering methods produced HA ceramics with crystal sizes greater than nanometer range. In this study, nano-sized HA powder was employed to fabricate dense nanocrystal HA ceramic by high pressure molding, and followed by a three-step sintering process. The phase composition, microstructure, crystal dimension and crystal shape of the sintered ceramic were examined by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. Mechanical properties of the HA ceramic were tested, and cytocompatibility was evaluated. The phase of the sintered ceramic was pure HA, and the crystal size was about 200 nm. The compressive strength and elastic modulus of the HA ceramic were comparable to human cortical bone, especially the good fatigue strength overcame brittleness of traditional sintered HA ceramics. Cell attachment experiment also demonstrated that the ceramics had a good cytocompatibility.
