多孔β-TCP骨支架材料孔壁表面纳米化研究

通过在多孔β-TCP骨支架材料的孔壁表面沉积类骨磷灰石层进行纳米化处理,结果表明,经模拟体液浸泡后可在多孔β-TCP材料孔壁表面形成具有纳米级精细结构的沉积层,晶粒形状为鳞片状;XRD、FTIR测试发现该沉积层为含有CO32-的磷灰石相,它具有与自然骨类似的化学组成和生物活性。另外,NaOH溶液预处理可有效促进类骨羟基磷灰石层的沉积速度,且沉积层趋于均匀化。     

Preparation and cell-materials interactions of plasma sprayed strontium-containing hydroxyapatite coating

The use of strontium-containing hydroxyapatite (Sr-HA) as a biomaterial has been reported recently. In vitro and in vivo studies have shown that Sr-HA promotes osteoblast response and stimulates new bone formation. In order to extend its usage to major load-bearing applications, such as artificial hip replacement, it has been proposed that the material could be used in the form of a coating on implant surfaces. This paper reports a preliminary study of biocompatibility of plasma sprayed Sr-HA coatings on a metallic substrate. Coatings of Sr-HA containing 10 mol% Sr²⁺ was produced on titanium alloy substrates. The coating exhibited good bonding with the substrate. The bioactivity of Sr-HA coating was evaluated in vitro by immersion in simulated body fluid (SBF). After immersion in SBF, Sr-HA coating exhibited great ability to induce apatite precipitation on its surface. The possible effects of cell-materials interactions of Sr-HA coating were examined by culturing osteoprecursor cells (OPC1) on coating surfaces. The effect of Sr-HA was also compared to a hydroxyapatite (HA) coating, which is widely used in orthopedics and dentistry. The results indicated that Sr-HA coating had good biocompatibility with human osteoblasts. OPC1 cells survived and proliferated well on the surface of coating. Sr-HA coating promoted OPC1 cells attachment, and more local contacts were produced on the surface. The presence of Sr stimulated OPC1 cell differentiation and ALP expression. No deleterious effect on ECM formation and mineralization was found with Sr-HA coating. The results indicated that Sr-HA coating had good mechanical properties and bioactivity in vitro.     

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.     

Effect of a bioactive glass-ceramic on the apatite nucleation on titanium surface modified by micro-arc oxidation

The aim of this work was to evaluate the ability of a bioactive glass-ceramic to induce the apatite nucleation on the titanium oxide layer produced by micro-arc oxidation. “In vitro” tests were carried out on a simulated body fluid solution in two different manners: one group was soaked in the SBF, while the other group was soaked together with the bioactive glass-ceramic. Results revealed that after 7 days, the specimens soaked in SBF were covered with an amorphous calcium phosphate layer, while the specimens soaked in SBF plus glass-ceramic formed a crystalline apatite layer, suggesting thus, that the glass-ceramic provides silanol groups that accelerated the hydroxyapatite apatite precipitation on the anodic TiO₂ layer.     

Transformations in Sol-Gel Synthesized Nanoscale Hydroxyapatite Calcined Under Different Temperatures and Time Conditions

Nano-hydroxyapatite (HAP) has been synthesized using sol-gel technique. Calcium nitrate tetrahydrate and potassium dihydrogen phosphate were used as precursors for calcium and phosphorus, respectively. A detailed study on its transformation during calcination at two crucial temperatures has been undertaken. The synthesized nanopowder was calcined at 600 and 800?°C for different time periods. The results revealed that the obtained powders after calcining at 600 and 800?°C are composed of hydroxyapatite nanoparticles. The nano-HAP powders were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA), and BET surface area analyzer techniques. The results indicate that crystallite size as well as crystallinity of synthesized HAP nanopowders increase with increase in calcination temperature as well as calcination time, but the effect of temperature is more prominent as compared to that of calcination time. TEM micrograph revealed the presence of majority of HAP powder particles as agglomerates and a few as individual particles. It also revealed that HAP produced after sintering at 600?°C is 26-45?nm in size, which is well in agreement with the crystallite size calculated using XRD data. TGA study showed the thermal stability of the as-synthesized nano-HAP powder. The BET surface area decreased with increase in calcination temperature and time. The results clearly demonstrate the significant role of calcination parameters on the characteristics of nano-HAP powders.     

Characterization of hydroxyapatite particles plasma-sprayed into water

Optimization of plasma spraying parameters for producing hydroxyapatite (HA) is usually based on the relationship between the spraying parameters and the coating characteristic. However, the microstructural evolution during the flight of melted HA particles is usually neglected. In this paper, HA powder was plasma-sprayed into water to preserve the morphology of the flying melted HA particles, and the microstructure and phase composition of the sprayed particles were examined and elaborated. A central hollow structure and some novel morphologies of the melted HA particles were found. The central hollow structure was suggested to result from gaseous P₂O₅ and H₂O decomposed from Ca₁₀(PO₄)₆(OH)₂ under high temperature, as well as the volume contraction of molten HA particle during cooling. The HA particles sprayed into water had a higher crystallinity and less impurity phase as compared with that of the HA coating. Furthermore, analysis on surface morphology and phase composition of the sprayed HA particles immersed in Simulated Body Fluid (SBF) seemed to demonstrate that the sprayed particles had a high bioactivity.     

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.     

In situ composite coating of titania-hydroxyapatite on commercially pure titanium by microwave processing

Microwave (MW) processing has been studied as an alternative method of hydroxyapatite (HA) based composite coatings on commercially pure titanium (CPTi) to enhance the bioactivity for orthopaedic and dental implant applications. The coating was formed by processing CPTi metal packed in HA and at 800 W microwave power for 22 min. The composition of the coating was found to be TiO₂ (rutile) as major phase along with HA as minor phase. The MW absorption of non-stoichiometric TiO₂ layer, which was grown during the initial hybrid heating, resulted in sintering of apatite particles interfacing them. The non-stoichiometric nature of TiO₂ was evident from the observed mid-gap bands in ultraviolet-visible diffusive reflectance (UV-VIS-DR) spectrum. The lamellar α structure of the substrate suggests that the processing temperature was above β transus of CPTi (1155 K). The oxygen stabilized α phase whose thickness increased with microwave processing time, was likely to be the reason for the increase in Young's Modulus and hardness of the substrate. The coating induced apatite precipitation in bioactivity test. The osteoblast cell adhesion test demonstrated cell spreading which is considered favourable for cell proliferation and differentiation. Thus, in situ composite coating of titania and HA on CPTi was obtained by a simple one-step process.     

悬浮液等离子喷涂制备FHA/CS复合涂层

目的 采用悬浮液等离子喷涂技术（SPS）在纯钛表面制备氟代羟基磷灰石/硅酸钙（FHA/CS）生物复合涂层。方法 利用X射线衍射仪（XRD）、傅里叶红外光谱仪（FT-IR）、扫描电子显微镜（SEM）及能谱仪（EDS）对复合涂层的物相组成、组织结构和显微形貌进行分析。通过动电位极化测试和体外生物活性测试,分析复合涂层在模拟体液（SBF）中的腐蚀行为和类骨磷灰石形成能力。通过电感耦合等离子体光谱仪（ICP）分析涂层中Ca2+的释放行为,评估复合涂层的化学稳定性。采用划痕法表征涂层的结合强度。结果 SPS制备的复合涂层具有粗糙的表面和层片堆叠结构。涂层中FHA和CS两相分布均匀,结晶性良好。复合涂层临界载荷达到111.43 N,比单一FHA涂层提高62.5%。与纯钛相比,涂层样品具有较高的腐蚀电位（Ecorr）和较低的腐蚀电流密度（Jcorr）。在SBF溶液中浸泡3天,涂层样品表面被类骨磷灰石完全覆盖。ICP结果表明,复合涂层中Ca2+释放速率低于单一CS涂层。结论 通过SPS在纯钛表面制备的FHA/CS复合涂层具有良好的生物活性、耐腐蚀性能和与基体的结合强度,复合涂层中FHA组分的存在有利于提高涂层的化学稳定性。     

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.     

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.     

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。     

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.     

HA/Mg生物复合材料的制备及其腐蚀特性

以纯镁为基体,以化学沉淀法制备的针状羟基磷灰石（HA）粉体为增强体,采用粉末冶金工艺制备了不同HA含量的HAp／Mg复合材料。对所制备复合材料的组织、物相以及在模拟体液（simulated body fluid,简称SBF）中的腐蚀行为进行了研究。结果表明：HA在烧结过程中与镁基体没有发生明显反应：HA对HA／Mg复合材料的密度、硬度及强度产生了不同程度的影响;同时HA加入可以提高复合材料在模拟体液中的抗腐蚀能力和抑制模拟体液的pH值增加,通过调整HA的体积分数可以调控复合材料的力学性能和腐蚀速率。     

Bioactive Glass-Ceramic Coatings Synthesized by the Liquid Precursor Plasma Spraying Process

In this study, the liquid precursor plasma spraying process was used to manufacture P₂O₅-Na₂O-CaO-SiO₂ bioactive glass-ceramic coatings (BGCCs), where sol and suspension were used as feedstocks for plasma spraying. The effect of precursor and spray parameters on the formation and crystallinity of BGCCs was systematically studied. The results indicated that coatings with higher crystallinity were obtained using the sol precursor, while nanostructured coatings predominantly consisting of amorphous phase were synthesized using the suspension precursor. For coatings manufactured from suspension, the fraction of the amorphous phase increased with the increase in plasma power and the decrease in liquid precursor feed rate. The coatings synthesized from the suspension plasma spray process also showed a good in vitro bioactivity, as suggested by the fast apatite formation when soaking into SBF.     

On the Electrodeposition of Ca-P Coatings on Nitinol Alloy: A Comparison Between Different Surface Modification Methods

In this study, a combination of surface modification process and the electrochemical deposition of Ca-P coatings was used for the modification of the Nitinol shape memory alloy. DSC, SEM, GIB-XRD, FT-Raman, XPS, and FTIR measurements were performed for the characterization of the samples. Results indicated that chemical etching and boiling of the samples in distilled water formed TiO film on the surface. After the chemical modification, subsequent aging of the sample, at 470 °C for 30 min, converted the oxide film to a stable structure of titanium dioxide. In that case, the treated substrate indicated a superelastic behavior. At the same electrochemical condition, the treated substrate revealed more stable and uniform Ca-P coatings in comparison with the abraded Nitinol substrate. This difference was attributed to the presence of hydroxyl groups on the titanium dioxide surface. Also, after soaking the sample in SBF, the needle-like coating on the treated substrate was completely covered with the hydroxyapatite phase which shows a good bioactivity of the coating.     

预钙化处理提高钽的表面生物活性

为提高钽的生物活性,对钽进行了NaOH溶液碱处理,利用模拟体液(SBF)浸泡实验探索碱处理的最佳浓度。碱处理后的钽又分别在CaCl2溶液和K2HPO4溶液中进行预钙化处理。钽经过0.7mol/L的碱处理后,在SBF中浸泡2周,表面即可被羟基磷灰石覆盖。经预钙化处理后,钽在SBF中浸泡4天,表面即可覆盖一层羟基磷灰石,说明预钙化大幅提高了钽的生物活性。其机理是预钙化处理可使样品表面迅速完成钙磷化合物的形核,浸入SBF以后羟基磷灰石可以迅速长大。     

In Vitro Bioactivity of Surface-Modified β-Ti Alloy for Biomedical Applications

Ti-15Mo (β-Ti) alloy was subjected to chemical followed by thermal treatment for the enhancement of in vitro bioactivity and corrosion resistance. The surface-modified specimens were characterized using scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDAX). The results indicated the formation of nanoporous layer and flake-like structure developed during chemical and subsequent thermal treatments. The in vitro bioactivity of the surface-treated β-Ti alloy was evaluated by immersing in simulated body fluid (SBF) solution. The formation of apatite particles was confirmed using Fourier transform-infrared spectroscopy, SEM, and EDAX analyses. Moreover, the electrochemical behavior of surface-modified specimens in SBF solution was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy. The results revealed that the surface-modified specimens exhibited higher potential value and lower current density when compared to untreated specimen. The EIS studies showed the formation of new layer, indicating the growth of apatite-like particles.     

Phase composition and in-vitro bioactivity of plasma sprayed calcia stabilized zirconia coatings

Zirconia coatings stabilized with different calcia content (12.8 mol%, 16 mol% and 30 mol%) were fabricated on titanium alloy substrates using atmospheric plasma spraying technology. The in-vitro bioactivity of coatings was evaluated by simulated body fluid (SBF) soaking test. The morphology and phase composition of the coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), micro Raman spectroscopy, energy dispersive spectrometry (EDS) and infrared spectroscopy (IR). The results showed that the apatite was formed on the surface of the calcia stabilized zirconia coatings soaked in SBF for 28 days and the formation ability of apatite decreased with the increase in calcia content of the coating. The bioactivity of zirconia coatings was thought to be related to the Zr-OH formed on their surfaces during the phase transformation in the presence of water. Osteoblast-like MG63 cells were cultured on the surfaces of the coatings to evaluate their cytocompatibility. Results showed that MG63 cell grew and proliferated well on all coating surfaces, indicating that plasma sprayed calcia stabilized ZrO₂ coatings were cytocompatible.     

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.