Effect of Hydroxide Ion Concentration on the Morphology of the Hydroxyapatite Nanorods Synthesized Using Electrophoretic Deposition

The effect of OH- concentration on the morphology of the hydroxyapatite (HA) nanorod synthesized using electrophoretic deposition (EPD) method has been investigated. The growth of HA nanorods was achieved on polished titanium substrates. The electrolyte used in this study was prepared by dissolving calcium acetate (Ca (CH3COO)2H)2O), and Ammonium dihydrogen phosphate (NH4H2PO4) in distilled water without any surfactant, and was maintained at 80-130°C. Two electrolytes with OH- concentration of 10-4 and 10-10 were prepared. A highly homogeneous HA nanorods deposited on the titanium substrates were obtained after 1 h in the electrolytes with higher OH- concentration of 10-4. On the other hand, a flower-shaped HA nanostructures composed of needle-like HA crystals were obtained in the electrolyte of lower OH- concentration of 10-10. The deposits were identified as HA crystal rods grown along the c axis and perpendicular to the substrate. The HA deposits were characterized by scanning electron microscopy (SEM) while detailed structural characterization was done using a transmission electron microscope (TEM) equipped with selected area electron diffraction (SAED) patterns.

Study of preparation of BG/HA gradient coating on titanium alloy by electrophoretic deposition method

In this paper, a gradient bioactive coating made from modified bioglass(BG) and hydroxyapatite(HA) was prepared by electrophoretic deposition method(EPD)on the surface of titanium alloy. Strong bonding between the matrix and BG/HA gradient coating was got by sintering. Crystal composition of the coating was analyzed by XRD. The characteristics of surface and cross section of the coating were observed by SEM. Adhesive strength of the coating was tested by pull method. The optimizing technological parameters were determined.

Electrophoretic Deposition of Hydroxyapatite Coating

Hydroxyapatite (HAP) coatings were deposited onto titanium substrates by electrophoretic deposition (EPD) fromethanol. The results indicated that the addition of very small amount of HCI resulted in a decrease in the aging timeas well as the suspension concentration required to obtain a coating. In addition, the results revealed the existenceof a critical saturated voltage (Vsat), which had significant effect on the quality of deposition. The mean interfacialshear strengths of HAP coatings after sintering were found to be greater than 13 MPa.

Electrophoretic Coating of Hydroxyapatite on Pyrolytic Carbon Using Glycol as Dispersion Medium

Hydroxyapatite （HA） coatings on pyrolytic carbon were produced via electrophoretic deposition （EPD） using glycol and ethanol as dispersion medium respectively. The effect of the solubility of HA in the dispersion medium on crack occurrence and adherence of the coating was investigated by means of scanning electronic microscope （SEM） and atomic absorption spectrometer （AAS）. The results show that the solubility of HA in glycol is higher than that in ethanol. The usage of glycol as a dispersion medium can reduce the possibility of crack formation and enhance the adhesive strength between the coating and the carbon substrate. The green coatings can be sintered under vacuum at 1 000 ℃ whether the coatings are obtained using ethanol or glycol as dispersion medium. No HA decomposition was observed up to 1 000 ℃ by vacuum sintering by X-ray diffraction （XRD） analysis.

Coating of calcium phosphate on biometallic materials by electrophoretic deposition

Although biometallic materials have been used as bone implant materials for a long time, they are still detected as foreign bodies by human immune system. Calcium phosphate coating, especially hydroxyapatite(HA) coating attracts special attention due to its good biocompatibility. Being one of the effective methods used to deposit HA coating onto the metallic implant, the electrophoretic deposition(EPD) was reviewed in detail, including the process of EPD, the advantages and disadvantages, the important processing factors and the microstructure and mechanical properties of the coating. Research results on the processing and the coating show potential application of EPD process to the biomedical materials surface modification. In addition, the nanoparticulate HA coating as a new trend in HA coating was also introduced.

Fabrication and In vitro Bioactivity of Robust Hydroxyapatite Coating on Porous Titanium Implant

Compared witli the traditional dental implant, TixOs■ manufactured by direct laser metal forming(DLMF) technology exhibits improved capability for bone osteointegration due to its porous surface structure, and has achieved remarkable clinical effect. However, like the traditional titanium and other alloyed implants, the porous titanium implant TixOsR also has relatively weak bioactivity. To address this issue, a proper surface modification method may be needed. Hydroxyapatite(HA) has been widely used in implant surface coating for its similar chemical composition to bone tissue and its osteoconductive properties. Thus, combining TixOs■ implants with hydroxyapatite can be an efficient way to enhance their bioactivity. We herewith reported a competent pulsed laser deposition(PLD) method of coating nano-sized HA thin film onto the porous TixOs■ implant. The HA coatings were characterized by means of scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), X-ray photoelectron spectroscopy(XPS) and focused ion beam(FIB) method, and nanocrystal sized thin HA films were identified on the surface of TixOs■ implants. The low cytotoxicity and improved cell proliferation ability of HA coated implants were further tested and verified using MC 3T3 E1 cells with the consideration of the controlling group. Our results show that a stable and bioactive HA tliin film is able to form on the surtace of the porous titanium implant by PLD method.This may benefit the fiirther clinical application of TixOs■ implants.

Fabrication and characterization of HAp /Al2O3 composite cating on titanium substrate

HAp/Al2O3 composite coating was fabricated onto micro-arc oxidized titanium substrate using a combination of electrophoretic depo-sition and reaction bonding process. SEM, EDS and XRD were employed to characterize the titanium substrate and as-prepared coat-ings. The interfacial bonding strength of the sintered composite coating was tested by shear strength testing experiment. Results show that the green form composite coating can be easily sintered with no cracks and de-composition at 850℃, the bonding strength to the substrate is significantly improved com-pared with the single HAp coating.

Effects of Laser Pulse Numbers on Surface Biocompatibility of Titanium for Implant Fabrication

Generally, materials with high biocompatibility are more appropriate for bone and tissue transplant applications, due to their higher effectiveness in the healing process and infection problems. This study presents the effects of laser surface texturing on the surface topography properties, roughness, and wettability of thin titanium sheets, which consequently enhance the biocompatibility of this material. Creating line patterns across the surfaces, the titanium samples are prepared using variety of laser parameters. The apatite inducing ability of each sample is tested through the use of simulated body fluid (SBF). The final biocompatibility level of titanium samples is analyzed through wettability, surface angle measurements, and average surface temperature profile. Overall, the effects of laser parameter, pulse numbers, upon the biocompatibility of titanium are thoroughly examined, with results indicating that a scanning speed of 100 μm/ms results in desirable bone type apatite inducing abilities across the surface of treated titanium sheets.

Preparation of Ti6Al4V/BG/HA graded coating by electrophoresis deposition in absolute alcohol medium

A codeposition of bioglass (BG) and hydroxyapatite (HA) on the substrate Ti6Al4V is realized in a nonaqueous solution system by inducing crystallization of HA on surface of the BG grain and electrophoresis deposition (EPD), and then a bioactive graded ceramic coating was obtained after sintering of the coating. This technique is a new method for making bioactive graded coating. The adhesive strength between the coating and the substrate reaches 18?MPa, and the better electrophoresis depositing parameters and optimal sintering procedure are obtained.

Production of "Tricalcium Phosphate/Titanium Dioxide" Coating Surface on Titanium Substrates

A new method for the production of the coating surface consisting of tricalcium phosphate （TCP） and titanium dioxide （TiO2） on titanium （Ti） substrates by using electrophoretic deposition （EPD） method has been developed.Crack occurrence on coating surface and hydroxyapatite （HA） decomposition into TCP,which are commonly encountered in EPD method,were used as an advantage in this study.HA nano-powders synthesized by acid-base method were used as the coating material.They were deposited on Ti substrates with different voltages and durations.Cracks on the deposited surface were observed by scanning electron microscopy （SEM）.Samples were sintered in air atmosphere to allow TiO2 growth from the Ti substrate to fill the cracks.SEM observation and X-ray diffraction （XRD） analysis proved the occurrence of complete decomposition of HA into TCP,TiO2 growth between cracks,and coalescence of TCP/TiO2 on coating surface.This type of coating surface is expected to increase the coating strength because of TiO2 growth in the cracks and its coalescence with TCP.

Inducing Macrophages M2 Polarization by Dexamethasone Laden Mesoporous Silica Nanoparticles from Titanium Implant Surface for Enhanced Osteogenesis

The study conveys an idea to enhance the osseointegration of titanium implant (Ti) through modulating macrophages M2 polarization. The ?100 nm spherical mesoporous silica nanoparticles (MSN) that compromised of ~4-nm-diameter nano? tunnels were synthesized by the conventional "sol-gel" method, into which the dexamethasone (DEX) was loaded (DEX@ MSN). The DEX@MSN could consistently release DEX and showed favorable cytocompatibility in RAW264.7 cells. The arginase-1 expression, a specific marker for macrophages M2 polarization, was also enhanced by DEX @ MSN treatment. Then, the Ti was pre-treated with anodization under 5 V to generate the titania nanotubes with ?30 nm diameter (NT-30) and the DEX @ MSN was introduced onto NT-30 surface via electrophoretic deposition, with the aid of chitosan. After optimizing the deposition parameters, the supernatants of RAW264.7 from the decorated implant surface could significantly promote the osteogenic differentiation of murine primary bone marrow mesenchymal stem cells. These findings demonstrate that delivery of DEX from implant surface can modulate the macrophages M2 polarization and result in favorable osteogenesis.

电化学沉积时间对碱预处理钛合金表面HA涂层的影响

采用碱预处理钛合金表面再电化学沉积的方法,研究了电化学沉积时间对羟基磷灰石(HA)涂层物相、形貌、生物活性及其与钛合金基体间结合强度的影响。结果表明,碱预处理钛合金表面制备的电化学沉积涂层主要由片状HA相组成,电化学沉积时间对涂层物相组成没有影响,但会影响涂层厚度;沉积时间60 min时得到的HA涂层较致密,与基体的结合强度达17.85 MPa。各沉积时间下得到的HA涂层均具有较好的生物活性,在模拟体液(SBF)中,CO_(3)^(2-)置换HA中的PO_(4)^(3-)进入磷灰石中形成类骨磷灰石CHA,呈馒头状,直径7~8μm,且在SBF中浸泡3 d,CHA可铺满HA表面。

钛表面氧化石墨烯涂层的抗菌性和细胞相容性研究

目的:探讨钛表面氧化石墨烯涂层的抗菌性和细胞相容性。方法:将氧化石墨烯水分散液作为电解液,在浓度分别为20、60、100、140μg/mL的条件下,通过电泳沉积在钛表面构建氧化石墨烯涂层,作为实验组,钛片作为对照组;采用激光拉曼光谱对涂层进行表征,利用多功能纳米力学测试仪对涂层的杨氏模量、维氏硬度和摩擦力进行分析;通过对变形链球菌和牙龈卟啉单胞菌的抗菌率检测来评价涂层的抗菌性能;采用CCK-8法评价涂层对人牙龈成纤维细胞的细胞增殖的影响。结果:经电泳沉积后的钛片表面形成一层均匀的棕黄色薄膜,且颜色随浓度增加而加深;拉曼光谱显示各实验组均检测到氧化石墨烯的特征峰;各组试件的杨氏模量和维氏硬度均表现为对照组最高,实验组数值随氧化石墨烯浓度增高而增高,但不具有统计学差异;划痕曲线表明,G140组最先出现转折点,G100组最后出现转折点;各组试件对变形链球菌和牙龈卟啉单胞菌的抗菌率均随氧化石墨烯浓度的增高而增高;CCK-8检测结果显示,G140组的细胞增殖率明显低于对照组。结论:通过电泳沉积技术可在钛表面成功制备氧化石墨烯涂层,不同浓度均未对钛片的机械性能造成明显影响,当制备浓度为100μg/mL时,对变形链球菌和牙龈卟啉单胞菌具有良好的抗菌活性,且对人牙龈成纤维细胞无明显细胞毒性。

钛合金钙磷涂层电沉积技术研究进展

钛合金表面电沉积钙磷涂层技术具有处理温度低、组织结构易控和经济高效等优势,在保持植体优良机械性能的同时提高生物活性,有望替代等离子喷涂技术。为了促进钛合金表面电沉积钙磷涂层技术的临床转化,首先简述钛合金表面电沉积钙磷涂层机理,然后详述近年来在电解液参数(钙磷比、添加剂、p H值和气氛)、外场条件(电场、温度、磁场、超声波)和沉积时间对钛合金表面电沉积钙磷涂层影响的研究进展。其中,钙磷比改变电解液中钙源和磷源离子的临界浓度;p H值调节电解液中磷源离子的存在形式,直接影响涂层的物相种类;添加剂通过与钙源、磷源、溶剂或沉积晶体发生静电吸引、配位或特征吸附等作用,能够进一步调控涂层的种类和形态;控制气氛可有效防止空气中CO_(2)对涂层物相产生影响;进一步通过电场、温度、磁场、超声波和沉积时间的调控,可以优化涂层的结构形态和性能。最后,阐述了钛合金表面电沉积钙磷涂层技术的现存问题,并对其未来发展方向做了展望。

电泳沉积羟基磷灰石生物陶瓷涂层的研究进展

羟基磷灰石 (hydroxyapatite ,HAP)生物陶瓷涂层被认为是目前最好的用于替代人体硬组织的一种生物医用材料。电泳沉积是一种全新的涂层制备方法 ,它可以解决传统HAP生物陶瓷涂层制备工艺上的各种不足。文中综合介绍了国内外有关电泳沉积HAP生物陶瓷涂层的研究报道 ,概述了电泳沉积的工艺流程和工艺参数 ,并对各种影响因素全面地进行了详细的探讨 。

在钛基上电泳沉积羟基磷灰石生物陶瓷涂层的研究

将羟基磷灰石(HAP)电泳沉积在钛基材上,得到了结构稳定的HAP生物陶瓷涂层。研究了电场强度、悬浮液温度、电泳时间、分散介质及HAP浓度对涂层形貌的影响。通过红外光谱仪(FTIR)和X射线衍射仪(XRD)对涂层的组成及结构进行了分析,并采用扫描电镜(SEM)对涂层煅烧前后的微观形貌进行了观察。结果表明:在正丁醇作为分散剂、悬浮液温度30℃、电场强度250V/cm、电泳时间300s以及HAP浓度5 0g/L的条件下可制得形貌较好的HAP生物陶瓷涂层;经二次电泳沉积及煅烧后得到的HAP生物陶瓷涂层均匀致密。

在非水溶液体系中电泳沉积Ti6Al4V/BG/HA梯度涂层

本工作的目的是探索制备钛合金表面生物活性梯度涂层的新方法 ,提高涂层的结合强度及稳定性 .通过诱导羟基磷灰石 (HA)在生物玻璃 (BG)颗粒表面的结晶 ,改变了生物玻璃表面的带电特性 ;采用电泳沉积 (EPD)法 ,在非水溶液体系中实现了BG和HA在阴极Ti6Al4V基体上的共沉积 ,经烧结获得了生物活性梯度陶瓷涂层 ,得到了一种制备生物活性梯度陶瓷涂层的新工艺 .用XRD对涂层的相组成进行了定性分析 ,结果表明涂层由HA ,榍石和玻璃组成 ;采用粘结拉伸法测定的涂层与基体结合强度大于 18MPa,用SEM观察涂层表面及断面的形貌 ,可见涂层表面较为平整 ,没有明显的裂纹 ;涂层与基体结合紧密 ,且存在一明显的界面梯度区域 .

悬浮液粉体含量对电泳沉积羟基磷灰石涂层的影响

从不同羟基磷灰石(hydroxyapatite,HA)粉体含量的悬浮液中,在钛表面电泳沉积HA涂层。采用扫描电镜、X射线衍射表征涂层的微观形貌及物相组成,通过黏结-拉伸实验测定涂层与基底的结合强度。结果表明:提高悬浮液的HA粉体含量,有助于提高电泳沉积HA涂层的致密性,改善其烧结性能,提高烧结致密化程度;HA涂层致密性的提高,有效地抑制了钛基底表面氧化反应,改善了涂层与基底的界面结合状态,使HA涂层与钛基底的结合强度从悬浮液HA粉体含量为5 g/L时的4.54 MPa,提高到悬浮液HA粉体含量为20 g/L时的19.92 MPa。

电泳沉积HA/Ti复合涂层的结合强度和热稳定性

为了制备均匀致密、结合强度较高的电泳陶瓷涂层,用正丁醇作分散介质,在Ti基底上电泳沉积HA/Ti复合涂层。研究了Ti基底处理、烧结温度控制以及悬浮液配方等因素对涂层结合强度的影响。用扫描电镜(SEM)对热处理后涂层形貌和结构进行观察,采用红外光谱仪(FTIR)、X射线衍射仪(XRD)、差示扫描量热仪(DSC/TG)对涂层的组成和热稳定性进行了表征。结果表明:用H2O2/NH3·H2O处理Ti基底,700℃下烧结,Ti含量为44.6%的HA/Ti复合涂层结合强度可达到23.2MPa。

阳极氧化TiN薄膜制备N掺杂纳米TiO_2薄膜及其可见光活性

室温下通过电泳沉积(EPD)的方法在Ti片表面制备TiN薄膜,然后对TiN薄膜进行阳极氧化得到N掺杂多孔纳米结构的TiO2薄膜.利用X射线衍射(XRD),X射线光电子能谱(XPS),扫描电子显微镜(SEM)及光电化学方法对得到的薄膜进行表征.XRD测试结果表明,经过阳极氧化并在350℃空气气氛中退火1h的薄膜中存在锐钛矿晶型的TiO2.XPS的结果表明,样品中的N元素取代部分O,且N的摩尔分数为0.95%.SEM显示,经阳极氧化后薄膜表面出现多孔纳米结构.光电化学测试结果显示,阳极氧化提高了N掺杂TiO2薄膜在可见光下的光电响应.经阳极氧化并热处理的薄膜在0V电位及可见光照射下光电流密度为2.325μA·cm-2,而单纯热处理的薄膜在相同条件下光电流密度仅为0.475μA·cm-2.阳极氧化得到纳米多孔结构提高了N掺杂纳米TiO2薄膜的表面积,从而对可见光的响应增大.