泡沫复制法制备多孔钛及表面水热碱处理改性

采用聚氨酯泡沫复制法成功的制备出孔径可控、孔隙率高且三维贯通的多孔钛.采用水热碱处理法对多孔钛进行表面改性,以提高其生物活性.改性后多孔钛的表面形貌发生了改变,呈均匀分布的三维网状微纳米结构.将改性后的多孔钛浸泡在SCPS中检测其矿化能力.研究结果表明,改性后的多孔钛能加速磷灰石的矿化,其中三维网状微纳米结构是加速矿化的主要因素.同时考察了改性后的多孔钛表面大鼠颅盖骨成骨细胞(MC3T3-E1)的黏附铺展情况.细胞培养表明细胞在改性后的多孔钛表面能较好的黏附铺展.上述研究结果表明水热碱处理改性后的多孔钛具有较好的生物活性及生物相容性.     

Synthesis of N-doped titanium oxide by hydrothermal treatment

N-doped TiO₂ nanoparticles have been prepared by continuous or batch treatment of the colloidal TiO₂ nanoparticles under hydrothermal conditions with formamide, nitric acid, ammonia or triethylamine. The optical absorption tail of the obtained photocatalysts near the band gap extended to the visible region around λ = 500 nm. The efficiency of nitrogen doping was strongly dependent on the kind of nitrogen compounds, treatment method as well as treatment temperature. The most effective N-doping could be accomplished by the batch treatment with a small amount of triethylamine, which showed the efficient photocatalytic activity for both the reduction of Ag⁺ ions and the degradation of methylene blue under visible light irradiation.     

Surface modification of titanium thin film with chitosan via electrostatic self-assembly technique and its influence on osteoblast growth behavior

Chitosan (Chi) and poly (styrene sulfonate) (PSS) were employed to surface modify titanium thin film via electrostatic self-assembly (ESA) technique in order to improve its biocompatibility. The surface chemistry, wettability and surface topography of the coated films with different number of deposited layers were investigated by using X-ray photoelectron spectroscopy (XPS), water contact angle measurement and atomic force microscopy (AFM), respectively. The results indicated that a full surface coverage for the outmost layer was achieved at least after deposition of five layers, i.e., PEI/(PSS/Chi)₂ on the titanium films. The formed multi-layered structure of PEI(PSS/Chi) _x (x ≥ 2) on the titanium film was stable in air at room temperature and in phosphate buffered solution (PBS) for at least 3 weeks. Cell proliferation, cell viability, DNA synthesis as well as differentiation function (alkaline phosphatase) of osteoblasts on chitosan-modified titanium film (PEI/(PSS/Chi)₆) and control sample were investigated, respectively. Osteoblasts cultured on chitosan-modified titanium film displayed a higher proliferation tendency than that of control (p < 0.01). Cell viability, alkaline phosphatase as well as DNA synthesis measurements indicated that osteoblasts on chitosan-modified titanium films were greater (p < 0.01) than those for the control, respectively. These results suggest that surface modification of titanium film was successfully achieved via deposition of PEI/(PSS/Chi) _x layers, which is useful to enhance the biocompatibility of the titanium film.     

水热法聚乙烯基吡咯烷酮表面修饰碳纳米管的研究

采用水热法利用两亲性聚乙烯基吡咯烷酮(PVP)对CNTs进行了表面修饰,通过TGA、FT-IR、SEM、接触角分析研究了改性CNTs的表面性质和分散特性.实验结果表明:水热法较常用的常压法相比,可以提高CNTs的PVP包覆率,且使PVP同CNTs之间具有更强的作用力,同时使处理效率有较大提高;PVP用量、保温时间和PV...     

Surface modification of titanium for load-bearing applications

Titanium and its alloys are extensively used in load-bearing metallic devices. They are bioinert material and, therefore, get encapsulated after implantation into the living body by a fibrous tissue that isolates them from the surrounding tissues. Here we report modification of titanium surface using bioactive tricalcium phosphates (TCP) and nanoscale TiO2 to enhance cell-materials interaction. We have introduced bioactivity in Ti using laser-assisted coating of TCP and by anodization to grow surface TiO2 at room temperature using a mixed aqueous solution of sodium fluoride, citric acid and sulfuric acid as electrolyte. TCP coating showed a columnar Ti grains at the substrate side of the coating and transitioned to an equiaxed grains at the outside. Coating hardness increased from 882 +/- 67 to 1029 +/- 112 Hv as the volume fraction of TCP increased in the coating. For TiO2 nanotubes, microscopic analysis showed tubes of 50 nm in diameter with wall thickness of 15 nm and typical length between 200 nm and 1 micron based on anodization times. Effects of TCP and nanoscale TiO2 coating on bone cell-material interaction were examined by culturing osteoprecursor cells (OPC1) on coated surfaces. Antibacterial activity analysis using metallic Ag via electrodeposition showed over 99% antibacterial activity against the growth of colonies of Pseudomonas aeruginosa.     

Surface modification of titanium carbide with carbyne-containing nanocoatings

The aim of this research is to investigate a novel approach to surface engineering of biomaterials that are based on transition metals of the groups IVA-VIA. The approach taken relies on the fact that, during the electropolishing of TiC surfaces, the removal of Ti atoms from the TiC surface surpasses that of C atoms. This leads to enrichment of the TiC surface with carbon. Transmission electron microscopic investigation showed that carbon-based films contain carbynes in the form of nanorod-like clusters with lengths in the range of 5-100 nm. This carbyne-containing layer is 50-100 nm thick. It was generalized that carbyne-containing nanofilms are formed on the carbide surface of transition metals of groups IVA-VIA during electropolishing. Since carbynes, being one-dimensional chain-like structures [(-C identical to C-)n/(=C=C=)n] with sp1 carbon-carbon hybridization, have the highest degree of biocompatibility because of their biological activity, the development of such surface bioengineering with carbynes extends applications of biomaterials based on transition metals of the groups IVA-VIA.     

Surface energy-mediated fibronectin adsorption and osteoblast responses on nanostructured diamond

Nanostructured diamond have potential applications in many biomedical related fields and demonstrated extraordinary capacity to influence cellular responses. Studying the surface property of nanodiamond and its influence to protein adsorption and subsequent cellular responses along with the mechanism behind such capacity becomes more important. Here the role of surface energy associated with nanostructured diamond in modulating fibronectin and osteoblast(OB, bone forming cells) responses was investigated. Nanocrystalline diamond(NCD) and submicron crystalline diamond(SMCD) films with controllable surface energy were prepared by microwave-enhanced plasma chemical vapor deposition(MPCVD) techniques. Fibronectin adsorption on the diamond films with varied surface energy values was measured via the enzyme-linked immunosorbent assay(ELISA) and the relationship between the surface energy and fibronectin adsorption was studied. The result indicated that fibronectin adsorption on nanostructured surfaces was closely related to both surface energy and material microstructures. The spreading and migration of OB aggregates(each containing 30–50 cells) on the NCD with varied surface energy values were also studied. The result indicates a correlation between the cell spreading and migration on nanodiamond and the surface energy of nanostructured surface.     

Compositional modification of titanium carbide powders by induction plasma treatment

Non-stoichiometric titanium carbide powders were treated in an r.f. induction plasma. The composition of plasma gas, reactor pressure and powder feed rate were changed as experimental parameters, but plate power was kept constant. As the titanium carbide powders passed through the plasma, they melted, partially evaporated, and finally solidified. During the in-flight process, compositional modification was noted involving lattice modification and a change of the non-stoichiometry of titanium carbide depending on the plasma and powder feeding conditions. These were mostly due to the removal of carbon and oxygen impurity in titanium carbide while melting. The -AES analysis indicated that the removal of carbon occurred in the plasma treatment. The deposits formed from the vapour phase consisted mainly of very fine cubic crystals, some tens of nanometres in size, with an appreciable number of vacancies at carbon sites.     

Surface modification of titanium oxide in pulse-modulated induction thermal plasma

Recently, it was reported that RF induction plasma of a pulse-modulated operating mode had been successfully generated, for the first time, at a sufficiently high electric power level for materials processing. The unique conditions in the plasma, such as a non-equilibrium situation at the instance of pulse-on and -off and the increase of chemically reactive radical species, as well as the time-dependent change of plasma temperature, is expected to offer the unique physico–chemical conditions necessary for materials processing. As the first step of the work directed to materials processing, the thermal and chemical interactions between plasma and solid materials were examined for both cases of pulse-modulated and continuous modes. Green compacts of titanium dioxide (TiO₂), whose characteristics strongly depend on the formation of lattice defects and the incorporation of hydrogen, were treated in Ar---H₂ plasma of continuous and pulse-modulated generation modes. The oxide disks were placed at the downstream of plasma flow. The sample position and the plasma generation pressure were changed as processing parameters. The plasma-treated specimens were characterized by X-ray diffractometry and the hydrogen content was measured. The plasma treatment gave a thermal effect, rather than a chemical one, on the surface of oxide specimens. The oxides were thermally reduced by the plasma treatment and showed a change of color at the surface, while XRD did not show a change of crystal structure. Comparing specimens treated in the pulse-modulated plasma with those treated in the continuous plasma, the disk specimens had less of a thermal effect on the plasma.     

Surface modification and ageing of PMMA polymer by oxygen plasma treatment

We present a study on ageing of polymethyl methacrylate (PMMA) polymer treated with oxygen plasma. Oxygen plasma was created with an RF generator operating at a frequency of 27.12 MHz and a power of 200 W. The oxygen pressure was 75 Pa. The samples were treated for different time from 5 s to 60 s. The chemical modifications of the surface after plasma treatment were monitored by XPS (X-ray photoelectron spectroscopy), while the wettability and ageing effects were studied by WCA (water contact angle measurements). The samples were aged in dry air or in water. In the case of dry air, the least pronounced ageing was observed for the sample treated for 60 s. For samples aged in water, however, the lowest ageing rate was observed for the sample treated for 5 s. The samples were ageing slightly faster in water than in air. We also investigated the temperature effect on ageing of plasma treated samples. A set of samples was stored in a refrigerator at 5 °C and the other set was placed into an oven at 50 °C. The ageing rate of the samples stored at 5 °C was significantly lower than for the samples stored at 50 °C, so cooling the samples help keeping the required surface properties.     

Surface modification of elongated one-dimensional titanium dioxide structures with ferromagnetic nanoparticles

Nanostructured TiO₂ in the form of elongated one-dimensional structures having a highly ordered layered morphology, with cobalt-containing agglomerates on their surface, has been prepared by hydrothermal treatment of CoTiO₃ powder in the presence of chitosan, a bioactive natural polymer. The synthesis products have been characterized by scanning electron microscopy, transmission electron microscopy, IR spectroscopy, X-ray diffraction, elemental analysis, and magnetic measurements. The structures have been shown to be up to several microns in length, and their typical width ranges from 100 to 400 nm. The one-dimensional structures retain high thermal stability at calcination temperatures of up to 800°C. After vacuum heat treatment at 600°C and above, the nanostructured material possesses anomalously high ferromagnetic characteristics.     

Surface modification of a novel porous titanium dioxide/glass composite

A novel technique is used to produce an open porous titanium dioxide/glass composite, named Ecopore, with promising structural and biological properties for the development as a bone graft. This study aims at a fast and lasting integration of the new material by means of biochemical surface modification. Surface etching of Ecopore, aminosilanization and covalent coupling of the cellular attachment mediator fibronectin was employed as modification strategy. In a comparison of different etching procedures, alkaline etching led to the highest density of amino functions after subsequent aminosilanization. Fibronectin was immobilized using a bifunctional aminoreactive PEG‐linker. This protein coating improved the attachment of human osteoblast‐like cells (HOB) on non‐porous Ecopore as displayed by vital staining. XTT metabolism assays indicated an enhanced HOB growth in the initial phase of cultivation on fibronectin‐coated versus non‐coated specimens. In a first feasibility study, cultivation of HOB on coated porous Ecopore cylinders with a median pore size diameter of 130 μm showed that cellular growth was uniform and dense on the external surface of the specimen, but was sparse in the interior pore system. Ecopore batches with larger pores will be modified and investigated in vitro and in vivo in the next step of the study.     

Direct synthesis of brookite-type titanium oxide by hydrothermal method using water-soluble titanium complexes

It was demonstrated that brookite-type titanium oxide can be directly synthesized by the hydrothermal treatment of novel water-soluble titanium complexes under basic conditions in the presence of an additive. In particular, single-phase brookite was synthesized from the titanium–glycolate complex at a pH of about 10 in the presence of excess NH₃ aqueous solution or ethylenediamine, and powder thus obtained consisted of rod-like nanosized particles. It was suggested that the structures of titanium complexes are important for the formation of brookite.     

钛纳米管的水热合成研究及应用进展

钛纳米管是一种新型一维管状纳米材料,合成方法中研究得最深入的是水热法。钛纳米管具有的特殊性质使其在催化、负载、光电化学、吸附和离子交换等领域有着潜在的应用前景。本文综述了近5年来研究者们对钛纳米管组成成分、形成机理、及水热条件对产物形貌影响的研究进展,介绍了其应用研究现状。     

Surface modification of titanium implants using bioactive glasses with air abrasion technologies

A growing number of surface treated titanium implants are routinely used in dental and orthopaedic surgery, with a view to enhancing integration capacity with osseous tissue. This study examines the use of bioactive glass 45S5 as an alternative abrasive and osteoproductive surface modification material. Abrasive blasting of commercially pure titanium with bioactive glass 45S5 produced an irregular finish with a surface roughness average (S_a) of 1.1 μm as determined by white light interferometry, backscattered and secondary electron microscopy. The roughness attained compares favourably with currently used implant designs. Further, Energy Dispersive X-ray Analysis (EDXA) and backscattered electron microscopy demonstrated that bioactive glass was distributed across the titanium surface and retained within fissures and roughened surface features. Being an osteoproductive material, this is advantageous as it is expected that the modified metallic surfaces will acquire osteopromotive properties, and thus be of benefit to the process of implantation in osseous tissue.     

激光熔覆化学处理钛合金表面改性的研究

采用两步走的方法实现了钛合金的表面改性，首先在钛合金表面进行激光熔覆CaO或CaCO3，得到冶金结合的复合涂层后，通过在磷酸等含磷酸根的溶液中浸泡CaOCa使涂层中的转变为磷酸盐，从而使钛合金表面具有生物活性。XRD和SEM分析表明，得到了活性涂层，涂层与基体的结合良好。     

Morphology control of titanium oxides by tetramethylammonium cations in hydrothermal conditions

The effect of tetramethylammonium cations (TMA⁺) on TiO₂ crystal morphology in hydrothermal conditions has been studied. The as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The morphologies including besom-like particle, nanosheet and nanotube have been observed. The different ways TMA⁺ cations in the hydrothermal bases affect the crystal growth manner are suggested to be responsible for the different morphologies of the as-synthesized samples.     

Effects of titanium surface modifications on bonding behavior of hydroxyapatite ceramics and titanium by hydrothermal hot-pressing

In order to improve the interface strength in the bonded body of hydroxyapatite (HA) ceramics and Ti disks prepared by a hydrothermal hot-pressing (HHP) method, the effects of Ti surface modification on the bonding behavior were investigated. The reaction layer composed of titanium dioxide and sodium titanate was formed on the Ti surface using a 5 M NaOH solution with the objective of increasing the interface strength between the Ti substrate and HA ceramics to be formed by the HHP method. Three conditions with different temperature and treatment times were tested to modify the Ti surface. A mixture of calcium hydrogen phosphate dihydrate and calcium hydroxide was used as a starting powder material for solidifying HA. Solidification of HA and its bonding with Ti were achieved simultaneously by using the HHP method at the low temperature as low as 323 K. 3-point bending tests were conducted to obtain an estimate of the interface fracture toughness of HA/Ti. The Ti surface modification conducted at 323 K for 2 h using the hydrothermal NaOH solution was shown to be most effective among the three conditions tested. The hydrothermal Ti surface modification enabled us to increase significantly the interface fracture toughness. The enhancement of the interface fracture toughness was possibly due to the presence of anatase formed on the Ti surface and the good adhesion in the bioactive layer.     

Surface modification of titanium 6-aluminum 7-niobium alloy with biodegradable polymer coatings

The aim of the study is to determine the effect of long-term exposure to Ringer's solution on the physical properties of biodegradable polymer coatings on the titanium 6-aluminum 7-niobium alloy substrate. 30 day, 60 day and 90 day research periods are applied. The work is performed on a titanium 6-aluminum 7-niobium alloy modified by sandblasting and anodic oxidation. Three biodegradable polymer coatings: poly(glycolide-ϵ-caprolactone); poly(glycolide-ϵ-caprolactone-L,L-lactide) and poly(D,L-lactide-glycolide), containing ciprofloxacin are used in the study. The coatings are deposited by dip-coating method. Topography, wettability, and adhesion of the coatings are analyzed. The analysis of the test results indicates that regardless of the type of coating and the number of dips, the obtained coatings are continuous, hydrophilic, map the topography of the substrate, and slight change roughness after exposure to Ringer's solution. After three months of exposure to Ringer's solution, an increase in wettability and, at the same time, a significant decrease in adhesion is observed. The poly(D,L-lactide-glycolide) coatings are characterized by the greatest adhesion to the substrate.