Bioactivity of bioresorbable composite based on bioactive glass and poly-L-lactide

Bioactive and bioresorbable composite was fabricated by a solvent evaporation technique using poly-L-lactide（PLLA） and bioactive glass （average particle size： 6.8μm）. Bioactive glass granules are homogeneously distributed in the composite with microcrack structure. The formation of hydroxyapatite（HA） on the composite in simulated body fluid（SBF） was analyzed by scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS）, X-ray diffraction（XRD）, and Raman spectra. Rod-like HA crystals deposit on the surface of PLLA/bioactive glass composite after soaking for 3 d. Both rod-like crystals and HA layer form on the surface for 14 d in SBF. The high bioactivity of PLLA/bioactive glass composite indicates the potential of materials for integration with bone.     

CaO-P2O5-Na2O-B2O3溶胶-凝胶玻璃陶瓷体外磷灰石的形成和生物活性

采用溶胶-凝胶法制备CaO-P2O5-Na2O-B2O3玻璃陶瓷前驱体粉末,经过烧结热处理获得以β-Ca2P2O7为主晶相,CaPO3(OH)为次晶相的玻璃陶瓷。将试样在模拟体液中浸泡不同时间,采用XRD,SEM和EDX分析B2O3对试样表面磷灰石形成的影响。将MC3T3-E1细胞与玻璃陶瓷复合培养,通过SEM观察细胞的粘附和增殖行为。结果表明:B2O3的加入可以有效抑制析晶,稳定玻璃结构;试样在模拟体液中浸泡7d后,玻璃陶瓷表面有大量羟基磷灰石形成;细胞在支架材料上培养3~7d,呈现出良好的粘附和生长;表明B2O3的加入可以促进磷灰石矿化层的形成,提高材料的生物活性。     

超音速氧焰喷涂HA/BG涂层的制备及表征

利用超音速氧焰喷涂(HVOF)在Ti6A14V基体上制备了羟基磷灰石(HA)/生物玻璃(BG)涂层,考察了涂层的相组成、表面形貌及生物活性.XRD显示:涂层的结晶相为HA,未检测到HA分解产物,添加生物玻璃不影响涂层的相组成;SEM结果表明:HA颗粒熔化较少,计算熔化比例为13%,BG颗粒以球形方式镶嵌在涂层表面,含量小于粉末中的比例:涂层浸泡在模拟体液中7天后发现:添加20%BG的涂层表面有类骨类磷灰石涂层生成,说明添加BG可以提高涂层的生物活性.     

Bone-like apatite formation on HA/316L stainless steel composite surface in simulated body fluid

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.     

Flame Spray Deposition of Titanium Alloy-Bioactive Glass Composite Coatings

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.     

Bioactive glass nanopowder and bioglass coating for biocompatibility improvement of metallic implant

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.     

纯钛镁离子改性表面磷灰石沉积、蛋白质吸附及成骨细胞初期反应的研究

钛广泛用于整形外科产品的制造,但其本质上属于生物惰性材料,因此必须通过表面改性改善骨传导性。镁(Mg)离子参与人体骨的新陈代谢,在骨组织的生长和矿化各阶段发挥着重要的生理作用,鉴于此,本研究通过一种简单可行的方法对钛表面进行镁离子改性。主要实验过程如下：首先将纯钛放入高浓度氢氧化钠(NaOH)溶液中进行碱化处理,然后再转移至稀氯化镁(MgCl2)溶液中进行离子交换,最后进行热处理,在纯钛试样表面形成了含有钛酸镁成分的3D纳米网状结构。对试样的表面形貌、粗糙度和化学组成进行了分析;考察了试样在模拟人工体液中诱导羟基磷灰石的能力;以牛血清白蛋白为模型,研究了表面改性对纯钛蛋白吸附能力的影响;评价了MC3T3-E1成骨细胞在试样表面的附着、铺展和增殖。与钠(Na)离子改性相比,镁离子改性加快了羟基磷灰石在试样表面的沉积,并明显促进了蛋白吸附,此外,镁离子改性促进了成骨细胞附着、铺展及随后的增殖。本研究所提出的方法能明显改善纯钛的生骨传导性,可用于种植体制造。     

热处理对碳／碳复合材料上碱液处理氧化钛镀层诱导沉积磷灰石和结合强度的影响

碳／碳复合材料具有良好的力学性能和生物相容性，料上制备了氧化钛膜层，并进行了碱液处理、真空热处理、但没有生物活性。采用离子束增强沉积技术在碳／碳复合材模拟体液浸泡和划痕试验。研究发现氧化钛膜层经过碱液处理形成的多孔网状钛酸钠凝胶层，可在模拟体液中诱导沉积出牛物活性磷灰石层。钛酸钠凝胶层经过热处理变得致密，诱导沉积磷灰石层的速度有所下降。划痕试验表明碱液处理氧化钛镀层的结合强度在热处理后略有提高，但膜层的结合性能受到碳／碳复合材料较软的限制。     

医用近β型钛合金TLM的碱液处理与生物活性

采用模拟体液浸泡法评价碱液处理TLM(Ti-25Nb-3Zr-2Sn-3Mo)合金的生物活性。钛合金TLM经过碱液处理后表面生成了钛(铌)酸钠凝胶层,凝胶层厚度随碱液浓度升高而增加。在模拟体液中浸泡43h后,碱液处理钛表面只有少量磷灰石晶核生成,而碱液处理TLM合金表面有五水磷酸八钙晶粒形成,磷灰石的形核也较多。钛合金TLM在碱液处理时生成的钛(铌)酸钠凝胶层厚于纯钛,而较厚的凝胶层使其生物活性提高。     

Bioactivity and cytocompatibility of plasma-sprayed titania coating treated by sulfuric acid treatment

Titania coatings were fabricated on titanium alloy substrate using atmospheric plasma spraying technology, and treated by sulfuric acid (H₂SO₄) at room temperature for 24 h. The as-sprayed and acid-treated titania coatings were soaked in simulated body fluid (SBF) to investigate the formation of apatite on their surfaces. Human mesenchymal stem cells (MSCs) were used to evaluate the cytocompatibility of titania coatings. The results indicated that bone-like apatite was formed on the surfaces of acid-treated titania coatings after soaked in SBF for a period of time. The concentration of sulfuric acid had an effected on the bioactivities of titania coatings. The bioactivity of titania coating could not be improved by 0.01 M sulfuric acid treatment. The MSCs could attach, grow and proliferate well on the surface of titania coatings. The results showed that plasma-sprayed titania coating after acid treatment exhibited favorable bioactivity and cytocompatibility.     

Effect of Ti-OH formation on bioactivity of vacuum plasma sprayed titanium coating after chemical treatment

The effect of Ti-OH groups on bioactivity of NaOH treated titanium coating was investigated in this paper. The NaOH-heat treatment was also applied to modify the titanium coating for comparison. The results show that the amount of Ti-OH groups was important to induce apatite formation on the treated titanium coating. When the NaOH treated titanium coating was exposed to SBF, it released Na⁺ ions from the sodium titanate layer on its surface into the SBF via exchanging with H₃O⁺ ions in the fluid and Ti-OH groups were rapidly formed on the surface. So the NaOH treated titanium coating has good bioactivity in simulated body fluid (SBF). The amount of Ti-OH groups on the titanium coating was reduced after heat treatment, so the bioactivity of NaOH-heat treated titanium coating was obviously affected.     

钛基体表面多级孔洞结构的制备和生物活性研究

目的通过调控钛基体表面的结构和特性,提高惰性钛基体表面的生物活性,改善其医用植入效果。方法采用碱热处理方法在钛基体表面构建多级孔洞结构,对改性后钛片的表面形貌、成分、结构、亲疏水性进行表征,评价钛片表面对类骨磷灰石的诱导能力。结果碱热处理使钛表面形成了多孔网状结构,孔洞包括微米级孔和200~300 nm的纳米孔,孔隙间隔介于微米至几百纳米之间。碱热处理后的钛片表面形成了含有大量羟基的氧化物层,主要成分为金红石型Ti O2和碱性钛酸盐,具有极好的亲水性,接触角仅约为12°。碱热处理钛片表面的三维多孔结构对磷灰石的生长有很好的诱导作用,矿化7天后,类骨磷灰石便完全覆盖表面,14天后的矿化效果更好。结论纯钛表面通过碱热处理法构建微纳多孔结构后,具有良好的诱导羟基磷灰石形成的能力,对其生物活性有促进作用。     

贝壳表面沉积片状磷灰石及其体外生物活性

采用溶液浸泡法将贝壳在37 ℃转化成磷灰石,借助XRD、FTIR、SEM、TEM等分析手段研究磷灰石的形貌、结构和体外生物活性.贝壳在磷酸缓冲溶液中浸泡24 h后,通过溶解-再结晶反应在其表面沉积上一层具有片状形貌的缺钙型磷灰石,其Ca/P比为(1.35±0.05).低温下制备的磷灰石结晶度较低,而且晶格内含有碳酸根和磷酸氢根离子.SBF实验表明,以贝壳为原料制备的磷灰石具有优良的体外生物活性,试样在SBF溶液中浸泡12 h后表面就沉积上一层类骨型磷灰石.预计溶液浸泡法制备的磷灰石可应用于骨支架材料或者填充材料.     

XPS study on potential suppression factors of suppressing in vitro apatite formation on anatase films prepared on various substrates

Multilayer anatase films were coated by sol-gel technology on various substrates such as stainless-steel, alumina, and glass, respectively. Their in vitro apatite-forming ability was examined by immersion in Kokubo's simulated body fluid (SBF; pH 7.4, 36.5 °C). Although on anatase layer on alkali-free glass apatite was deposited within 7 d, no apatite was found on anatase deposited onto stainless steel, alumina or glass substrates within 7 d to prove they were bioinert. X-ray photoelectron spectroscopy was able to detect chromium, aluminum, or sodium on the surface of the anatase films. This indicated that these ions possibly inhibited the in vitro apatite-forming ability.     

多孔钛表面梯度磷灰石涂层的简单化学法制备

通过碱液处理或碱热处理并在模拟体液(SBF)中浸泡，在多孔钛表面制备了具有梯度结构的类骨磷灰石层。结果表明，碱液处理使多孔钛表面形成了网状多孔结构，组成为钛酸钠、金红石等。热处理后磷灰石在多孔钛表面的初期沉积更均匀。涂层中钙，磷、氧以及钛元素的含量随深度而变化，形成了梯度结构。具有表面梯度磷灰石涂层的多孔钛有望用于临床矫形，以提高种植体的生物活性和骨结合强度。     

生物活性多孔钽支架的构建及其初步生物学评价

表面生物活性涂层构建是提升金属内植物骨整合能力的有效途径,本研究利用电化学沉积技术在多孔钽支架表面构建生物活性羟基磷灰石(HA)涂层。通过接触角和比表面积测试发现,HA涂层的构建显著提升了多孔钽表面亲水性,并增加了其比表面积。利用模拟体液浸泡试验评估支架生物活性,发现仅浸泡3天后,多孔钽支架表面就已被类骨磷灰石沉积所覆盖。建成骨细胞培养模型,通过激光共聚焦观察及细胞增殖测试发现,所有支架均具有良好的细胞相容性。并且,细胞共培养5天后,HA涂层化多孔钽支架表面细胞的增殖率分别是未改性材料组和空白对照组的1.1和1.4倍,呈现了更大的促细胞增殖潜力。本研究中所制备的生物活性多孔钽支架具备快速诱导类骨磷灰石沉积能力,能够促进成骨细胞在其表面的贴附和增殖,在骨修复领域具有较大的临床应用前景。     

Characterization of plasma-sprayed hydroxyapatite/TiO2 composite coatings

To enhance the bonding between hydroxyapatite (HA) coating and titanium alloy substrate, HA/TiO₂ composite coatings have been fabricatedvia plasma spraying. Bonding strength evaluation, simulated body fluid tests, and cell culturein vitro were carried out to characterize the composite coatings. The results obtained showed that the addition of TiO₂ to HA coating improved the bonding strength of the coating significantly. After being immersed in simulated body fluid (SBF) for a period, the surfaces of HA/TiO₂ composite coatings were completely covered by carbonate-containing apatite, which indicated that the coatings possess good bioactivity. Thein vitro cell culture indicated good cytocompatibility for HA/TiO₂ composite coatings.     

Microstructure and in vitro bioactivity of laser-cladded bioceramic coating on titanium alloy in a simulated body fluid

In order to obtain bioactivity on the surface of titanium alloy, the bioceramic coating on Ti–6Al–4V was designed and fabricated by laser cladding. The microstructure and bioactivity of laser-cladded bioceramic coating were investigated in vitro via soaking in a simulated body fluid (SBF). The results indicated that the laser-cladded bioceramic coating was metallurgically bonded to the substrate and contained such bioactive phases as hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). A bone-like apatite layer was spontaneously formed on the surface of laser-cladded coating merely soaked in SBF for 7 days. And the appearance of flake-like and cotton-like morphology, which is the characteristic morphology of apatite, offered an advantageous condition for osseo-connection. The formation ability of apatite was remarkably accelerated on the surface of laser-cladded bioceramic coating compared with the untreated titanium alloy substrate.     

TiO2-Bioactive Glass Nanostructure Composite Films Produced by a Sol-Gel Method: In Vitro Behavior and UV-Enhanced Bioactivity

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.     

Bioactivity,in-vitro corrosion behavior,and antibacterial activity of silver–zeolites doped hydroxyapatite coating on magnesium alloy

Mg-based alloys received significant attention for temporary implant applications while, their applications have been limited by high degradation rate. Therefore, silver–zeolite doped hydroxyapatite (Ag-Zeo-HAp) coating was synthesized on TiO₂-coated Mg alloy by physical vapour deposition (PVD) assisted electrodeposition technique to decrease the degradation rate of Mg alloy. X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FE-SEM) images showed the formation of a uniform and compact layer of Ag-Zeo-HAp with a thickness of 15 μm on the TiO₂ film with a thickness of 1 μm. The potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) tests indicated that corrosion resistance of Mg-Ca alloy was considerably increased by the Ag-Zeo-HAp coating. The bioactivity test in the simulated body fluid (SBF) solution showed that a dense and homogeneous bonelike apatite layer was formed on the Ag-Zeo-HAp surface after 14 d. Investigation of antibacterial activity via disk diffusion and spread plate methods showed that the Ag-Zeo-HAp coating had a significantly larger inhibition zone (3.86 mm) towards Escherichia coli (E. coli) compared with the TiO₂-coated Mg alloy (2.61 mm). The Ag-Zeo-HAp coating showed high antibacterial performance, good bioactivity, and high corrosion resistance which make it a perfect coating material for biomedical applications.