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1.
Bioactive and bioresorbable composite materials were fabricated from poly-L-lactide and bioactive glass (average particle size 6.8 μm) by a solvent evaporation technique. Cellular cultivation in vitro and MTT assay were conducted for evaluating the influence on morphology, growth and proliferation of cultured fibroblasts. The results of cytotoxicity testing show that cells cultured in extracts of PLLA/BG and on the surface of composites demonstrate normal growth and proliferation. The bioactive glass in PLLA composite facilitates both adhesion and proliferation of rat fibroblasts on PLLA/bioactive glass composite film.  相似文献   

2.
Hydroxyapatite/titania (HA/TiO2) double layers were coated onto Ti scaffolds throughout for orthopaedic applications by sol-gel method. Differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and X-ray diffractometry (XRD) were used for the characterisation of the phase transformations of the dried gels and coated surface structures. Scanning electron microscope (SEM) equipped with energy dispersive spectrometry (EDS) was used for the observation and evaluation of the morphology and phases of the surface layers and for the assessment of the in vitro tests. The in vitro assessments were performed by soaking the HA/TiO2 double coated samples into the simulated body fluid (SBF) for various periods. The TiO2 layer was coated by a dipping-coating method at a speed of 12 cm/min, followed by a heat treatment at 600 ℃ for 20 min. The HA layer was subsequently dipping-coated on the outer surface at the same speed and then heat-treated at difference temperatures. The results indicat that the HA phase begins to crystallize after a heat treatment at 560 ℃. The crystallinity increases obviously at 760 ℃. SEM observations find no delamination or crack at the interfaces of HA/TiO2 and TiO2/Ti. The HA/TiO2 coated Ti scaffolds displays excellent bone-like apatite forming ability when it is soaked into SBF. Ti scaffolds after HA/TiO2 double coatings can be anticipated as promising implant materials for orthopaedic applications  相似文献   

3.
SiO2 functional films were deposited on the surface of titanium by plasma assisted chemical vapour deposition(PACVD) and the composition of films was studied by XPS. Samples deposited with SlOE films were immersed in different concentration simulated body fluid(SBF) for biomimetic deposition of hydroxyapatite(HA). The results show that SiO2 functional films deposited on titanium surface with PACVD have good bioactivity. Hydroxyapatite is formed while titanium coated with SlOE is immersed in simulated body fluid for seven days.  相似文献   

4.
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.  相似文献   

5.
This work aimed to fabricate magnesium zinc/hydroxyapatite(Mg–Zn/HA) composite via powder metallurgy method and to develop a mathematical model to predict the compressive strength of the composite using response surface methodology method. The effect of various mechanical milling parameters, milling speed(200–300 r/min), ball-to-powder weight ratio(5–12.5)and HA content(2.6–10 wt%) on the compressive strength of Mg–Zn/HA composite was investigated. The model shows that high compressive strength of Mg–Zn/HA composite was achieved when the powders were prepared with high milling speed and ball-topowder weight ratio and low HA content. The mathematical model was adequate with error percentage lower than 3.4%. The microstructure of Mg–Zn/HA composite with different process parameters revealed that fine microstructure was observed at high milling speed and ball-to-powder weight ratio while agglomeration of HA was found in composite with 10 wt% HA. The agglomeration of HA led to degradation of interfacial bonding strength between matrix and reinforcement phases and hence decreased the overall compressive strength of Mg–Zn/HA composite. Biodegradation test revealed that sample with higher HA content had more weight gain and there was more formation of hydroxyapatite. Mg–Zn/HA composite with 8 wt% HA was found to be the best candidate for implant application because it had considerable compressive strength and good biodegradation properties.  相似文献   

6.
The effects of Nd addition on corrosion behavior of Mg66Zn30Ca4 amorphous alloys in simulated body fluids (SBF) were studied in this paper. Electrochemical properties of the samples before and after corrosion were determined. Surface morphologies of samples after immersion in SBF at 37 ℃ for different times were observed under scanning electron microscope (SEM). Results show that the corrosion resistance of Mg-based alloys in SBF is improved with the addition of Nd element. The electrochemical properties indicate that microalloying Nd element to the alloys leads to an ennoblement in the open circuit potentials of the alloys and a decrease in the anodic current density in SBF, especially for the Mgee66-xZn30Ca4Ndx alloys with Nd content of 1.0at.%-1.5at.%. It was observed that the surface morphologies of the alloys immersed in SBF change with the Nd addition. A flake- like structure parallel to the alloy substrate formed on the surface of 1.0at.% Nd-containing alloy immersed in SBF for 7 days improves the corrosion resistance of the amorphous alloys by blocking the corrosion liquid from attacking the alloys.  相似文献   

7.
Current--voltage (I--V) and capacitance-voltage (C--V) characteristics of Au/p-CZT contacts with different surface treatments on cadmium zinc telluride (CZT) wafer's surface were measured with Agilent 4339B high resistance meter and Agilent 4294A precision impedance analyzer, respectively. The Schottky barrier height was 0.85 +0.05, 0.96+ 0.05 eV for non-passivated and passivated CZT crystals by I-V measurement. By C-- V measurement, the Schottl~ barrier height was 1.39+ 0.05, 1.51 + 0.05 eV for non-passivated and passivated CZT crystals. The results show that the passivation treatment can increase the barrier height of the Au/p-CZT contact and decrease the leakage current. The main reason is that the higher barrier height of Au/p-CZT contacts can decrease the possibility for electrons to pass through the native TeO2 film. Most of the applied voltage appears on the depleted layer and there is only a negligible voltage drops across the nearly undepleted region. Furthermore, the electric field in the depleted layer is not uniform and can be calculated by the depletion approximation. The maximum electric field of CZT crystals is Eml= 133 V/cm at x=0 for non-passivated CZT crystal and Em2=55 V/cm for passivated CZT crystal, respectively.  相似文献   

8.
Sn-SnSb alloy was synthesized by reducing a aqueous solution containing Sn(Ⅱ) and Sb(Ⅲ) salts with NaBH4 in the presence of sodium citrate. The product was characterized by X-ray diffractometry(XRD) and scanning electron microscopy(SEM). Sn-SnSb/graphite composite powders were prepared by mechanical milling and the mass fraction of graphite was increased from 20% to 50%. The effect of graphite content on the electrochemical performance of Sn-SnSb/graphite composite electrode was investigated. The results show the increase of graphite content is in favor of enhancing the first charge-discharge efficiency and improving the cycle performance, but the capacity of the composite electrode decreases with increasing content of graphite.  相似文献   

9.
Graphene-reinforced copper composites recently have attracted more attention, since they exhibited excellent mechanical properties and could be used widely in many fields. Few-layer graphene (FLG) and copper powder were mixed by ball milling to produce homogeneous composite powders. Then, FLG-reinforced copper composites (FLG/Cu) were fabricated by spark plasma sintering (SPS) using the composite powders with a FLG volume fraction of 2.4 vol%. The effects of the rotating speed and the time of ball milling were analyzed based on the microstructure evolution and properties of the FLG/Cu composites. Obvious strengthening effect of FLG was found for the composites, and the conductance of the composite reaches 70.4% of IACS. The yield strength of the composite produced by ball milling at a speed of 100 r/rain for 4 h is 376 MPa, which is 2.5 times higher than that of copper and higher than that of copper composite enhanced by 5 vol% CNTs (360 MPa). The defects produced in FLG with the increase of rotating speed and time could reduce the mechanical and conductive properties of the composites.  相似文献   

10.
Sodium silicate (water glass) pretreatment before phosphating, silicate post-sealing after phosphating and adding silicate to a traditional phosphating solution were respectively carried out to obtain the improved phosphate coatings with high corrosion resistance and coverage on hot-dip galvanized(HDG) steel. The corrosion resistance, morphology and chemical composition of the coatings were investigated using neutral salt spray(NSS) tests, scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). The results show that pretreatment HDG steel with silicate solutions, phosphate coatings with finer crystals and higher coverage are formed and the corrosion resistance is enhanced. Adding silicate to a traditional phosphating solution, the surface morphology of the coatings is nearly unchanged. The corrosion resistance of the coatings is mainly dependent on phosphating time. Phosphating for a longer time (such as 5 min), the corrosion resistance, increasing with concentration of silicate, is improved significantly. Post-sealing the phosphated HDG steel with silicate solutions, the pores among the zinc phosphate crystals are sealed with the films containing Si, P, O and Zn and the continuous composite coatings are formed. The corrosion resistance of the composite coatings, related to the pH value, contents of hydrated gel of silica and Si2O^2- 5 and post-sealing time, is increased markedly. The improved coatings with optimal corrosion resistance are obtained for phosphating 5 min and post-sealing with 5 g/L silicate solution for 10 min.  相似文献   

11.
Powders of titanium alloy (Ti-6Al-4V) and bioactive glass (45S5) were deposited by flame spraying to fabricate composite porous coatings for potential use in bone fixation implants. Bioactive glass and titanium alloy powder were blended and deposited in various weight fractions under two sets of spray conditions, which produced different levels of porosity. Coatings were characterized with cross-sectional optical microscopy, x-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Immersion testing in simulated body fluid (SBF) was conducted for 0, 1, 7, and 14 days. Hydroxyapatite (HA) was found on the bioactive glass-alloy composite coatings after 7 days of immersion; no HA was observed after 14 days on the pure titanium alloy control coating. The HA formation on the alloy-bioactive glass composite coating suggests that the addition of bioactive glass to the blend may greatly increase the bioactivity of the coating through enhanced surface mineralization.  相似文献   

12.
Electrophoretic deposition (EPD) methods have been developed for the fabrication of composite bioactive glass–hydroxyapatite (HA)–chitosan and bioactive glass–HA–alginate composite coatings. Two different strategies have been utilized, which are based on the use of cationic chitosan and anionic alginate biopolymers. The mechanism of cathodic deposition of chitosan is based on the pH increase at the cathode surface, whereas the pH decrease at the anode surface enabled the deposition of alginate coatings. The use of chitosan and alginate enabled the electrosteric stabilization and deposition of bioactive glass and HA particles. Composite coatings were obtained on various conductive substrates and studied by thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The composition of the coatings can be varied by variation of bioactive glass and HA concentrations in the suspensions. The proposed method offers the advantages of room temperature fabrication of bioactive composite coatings that are suitable for biomedical applications.  相似文献   

13.
We report on poly(ε-caprolactone) (PCL) containing bovine bone hydroxyapatite (HA) and hydroxyapatite-silver (HA-Ag) composite nanofibers prepared via an electrospinning process for the biomedical applications. Bioactivity test was conducted by incubation in simulated body fluid (SBF). The morphology, structure and thermal properties of the PCL, PCL/HA and PCL/HA-Ag composite nanofibers before and after immersion in SBF were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy and thermogravimetry (TGA). SEM images revealed that the nanofibers are well-oriented and incorporated the HA-Ag nanoparticles well. The SBF incubation test confirmed that the fast formation of apatite-like materials suggests in vitro bioactive behavior of the nanofibers. Mechanical study revealed that the yield stress of PCL/HA-Ag composite nanofibers showed a higher value than that of PCL/HA composite, possibly due to the addition of metallic Ag nanoparticles. This study demonstrated that electrospun PCL/HA and PCL/HA-Ag composite nanofibers activates bioactivity and supports growth of apatite-like materials.  相似文献   

14.
Preparation and characterization of bioactive glass nanopowder and development of bioglass coating for biocompatibility improvement of 316L stainless steel (SS) implant was the aim of this work. Bioactive glass nanopowder was made by sol–gel technique and transmission electron microscopy (TEM) technique was utilized to evaluate the powders shape and size. The prepared bioactive glass nanopowder was immersed in the simulated body fluid (SBF) solution at 37 °C for 30 days. Fourier transform infrared spectroscopy (FTIR) was utilized to recognize and confirm the formation of apatite layer on the prepared bioactive glass nanopowder. Bioactive glass coating was performed on SS substrate by sol–gel technique. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) techniques were used to investigate the microstructure and morphology of the coating. Electrochemical polarization tests were performed in physiological solutions at 37 °C in order to determine and compare the corrosion behavior of the coated and uncoated SS specimens. Cyclic polarization tests were performed in order to compare the pitting corrosion resistance of the coated and uncoated SS specimens. The results showed that the size of bioactive glass powder was less than 100 nm. The formation of apatite layer confirmed the bioactivity of bioglass nanopowder. Bioactive glass coating could improve the corrosion resistance of 316L SS substrate. Bioactive glass coated 316L SS showed more pitting corrosion resistance in compare with pristine samples. It was concluded that by using the bioactive glass coated 316L SS as a human body implant, improvement of corrosion resistance as an indication of biocompatibility and bone bonding could be obtained simultaneously.  相似文献   

15.
目的研究水热时间对TC4钛合金微弧氧化膜合成羟基磷灰石(HA)的影响。方法对TC4钛合金微弧氧化膜进行不同时间的水热合成处理,分析其微观形貌、成分及相结构,观察其在模拟体液中浸泡5周后的形貌及结构变化。结果水热处理提高了微弧氧化膜的Ca/P摩尔比,使非晶态钙磷化合物转化为HA晶体,随着水热时间的延长,HA衍射峰数量增多且强度增加。在模拟体液中浸泡5周后,微弧氧化膜表面仅有微量磷酸钙形成,而如水热合成后再浸泡,氧化膜表面的HA几乎完全转化为磷酸钙。结论水热处理有助于钛合金微弧氧化膜表面合成HA晶体。在8 h内,水热时间越长,氧化膜表面的HA含量越高,模拟体液中浸泡后形成的磷酸钙也越多,与人体的相容性越好。  相似文献   

16.
为了改善钛合金种植体在体液中的腐蚀及摩擦腐蚀行为,延长其在人体环境中的服役时间,在微弧氧化 (MAO)膜层上采用溶胶凝胶(Sol-gel)法于羟基磷灰石(HA)和氧化石墨烯(GO)的混合溶胶中浸渍提拉成膜,从而在 Ti6Al4V 合金表面成功地制备了 GO/ HA/ MAO 复合膜层。 结果表明,MAO 膜层表面的微孔及微球被 GO/ HA 薄膜有效的覆盖且较为致密;膜层的物相组成主要为金红石相及锐钛矿相的 TiO2、HA、SiO2 和GO;根据电化学腐蚀和摩擦腐蚀结果分析知,GO/ HA/ MAO 复合膜层在模拟体液(SBF)中的耐蚀性及耐摩擦腐蚀性相比于 MAO 膜层和 Ti6Al4V 基体均得到了显著提高。  相似文献   

17.
利用H2O2和NaOH溶液对近等原子比NiTi记忆合金(SMA)进行复合活化处理,并采用XRD,SEM,XPS,FTIR等研究了活化处理后NiTi SMA的表面结构及其在模拟体液(SBF)中磷灰石涂层的仿生沉积过程.结果表明:复合活化处理后NiTi SMA表面为贫Ni、富含Ti-OH的蠕虫状活性层,由结晶度较低的TiO2,钛酸纳(Na2TiO3)及少量的Ni2O3组成,在SBF中表面活性层诱导磷灰石形核及生长,短期内在镍钛基体表面获得了理想的磷灰石层.  相似文献   

18.
The aim of this study is to develop TiO2, titania, -based composite films for 316 stainless steel substrate and to improve their apatite-forming activity. A series of sol-gel derived bioactive glass (49S) and bioactive glass (49S)-TiO2 films were deposited on the 316L stainless steel substrates by the spin-coating method. Amorphous bioactive glass (49S) film and polycrystalline titania-bioactive glass composite films were obtained after annealing the deposited layers at 600 °C. The microstructure and in vitro bioactivity of the composite films as well as the effect of titania nanopowder content and ultra violet (UV) irradiation on the in vitro bioactivity were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). While bioactivity tests are often carried out within 28-day periods, SEM and EDS data show that, after soaking in SBF for just 7 days, the prepared composite surfaces are covered with an apatite layer. The grown apatite layer consists of spherulites formed by nanosized needle-like aggregates. Fourier transform infrared spectroscopy investigations confirm apatite formation and suggest that the formed apatite is carbonated.  相似文献   

19.
HA/316L stainless steel(316L SS) biocomposites were prepared by hot-pressing technique. The formation of bone-like apatite on the biocomposite surfaces in simulated body fluid(SBF) was analyzed by digital pH meter, plasma emission spectrometer, scanning electron microscope(SEM) and energy dispersive X-ray energy spectrometer(EDX). The results indicate that the pH value in SBF varies slightly during the immersion. It is a dynamic process of dissolution-precipitation for the formation of apatite on the surface. With prolonging immersion time, Ca and P ion concentrations increase gradually, and then approach equilibrium. The bone-like apatite layer forms on the composites surface, which possesses benign bioactivity and favorable biocompatibility and achieves osseointegration, and can provide firm fixation between HA60/316L SS composite implants and human body bone.  相似文献   

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