择优取向类骨磷灰石涂层的制备与结构分析

纯钛表面用稀硫酸和盐酸的混合液处理12h,10M/L的NaOH在80℃下处理48h,并在600℃下热处理1h。将化学处理后的试样浸泡在模拟体液(SBF)中,试样表面形成择优取向生长的类骨磷灰石涂层。该磷灰石层由片状的晶粒组成,片状晶粒的长度在10-20μm之间,XRD分析表明该类骨磷灰石层的(002)晶向处特征峰为最强。该类骨磷灰石层的钙磷比约为1.4,为缺钙的类骨磷灰石层。     

碳酸羟基磷灰石的生物矿化研究

采用湿化学法制备了B型替代为主的碳酸羟基磷灰石(CHA)和羟基磷灰石(HA).利用体外实验方法(in vitro)以及XRD、SEM、FTIR、AAS等手段研究了HA和CHA在模拟生理溶液(SBF)中的降解过程、表面反应产物和生物矿化机理.研究结果表明,CHA具有较高的生物活性,在SBF中浸泡后可形成表面类似天然骨中矿物的碳酸羟基磷灰石层(HCA).材料的组成、溶解度和表面能对矿化层微晶的成核有重要作用.     

两步电化学法制备羟基磷灰石/氧化铝复合生物涂层的研究

研究旨在开发一种可应用于医用金属表面生物学改性的复合生物陶瓷涂层。通过先阳极氧化、再电沉积的两步电化学方法成功制备了羟基磷灰石(hydroxyapatite,HA)／Al2O3复合生物涂层。利用扫描电子显微镜(SEM)研究了阳极氧化Al2O3(anodic aluminum oxide,AAO)膜的表面形貌与HA／Al2O3复合涂层的表面及截面形貌结构;用X射线衍射仪(XRD)、Fourier变换红外光谱仪(FT-IR)与能谱仪(EDS)表征了复合涂层的物相组成;用等离子原子发射光谱仪(ICP-AES)和粘接拉伸试验分别测定涂层在模拟体液(SBF)中的体外行为和浸渍后涂层间的结合强度,结果表明：所制备的HA含有少量碳酸根,在SBF中呈现优良的稳定性并能诱导新的磷灰石层的形成;HA底部嵌入AAO膜的孔洞中形成互锁界面,经模拟体液处理后两者之间结合强度为3．2MPa。     

紫外辐照诱导等离子体喷涂氧化钛涂层的生物活性

采用大气等离子体喷涂技术在钛合金表面上制备常规和纳米结构TiO2涂层.考察了TiO2涂层经紫外光辐照后浸泡于模拟体液(simulatedbody fluid,SBF)中的生物活性.研究涂层表面状态、紫外光辐照时间和辐照介质对TiO2涂层生物活性的影响.结果表明:经紫外光辐照后的纳米TiO2涂 层在SBF中可诱导类骨磷灰石在其表面形成,显示了良好的生物活性,但常规TiO2涂层和磨去表面的纳米TiO2涂层无此种现象发生.紫外光辐照处 理时间增长有利于类骨磷灰右的生成.在SBF、水、空气中进行紫外光辐照的纳米TiO2涂层表面均有类骨磷灰石生成,但在水中进行紫外光辐照处 理的涂层显示较低的生物活性.     

富含钙磷的多孔氧化钛膜及其生物活化机理

在不同电压下,钛经微弧氧化在表面形成富含钙磷的多孔氧化钛膜。通过模拟体液浸泡实验检测磷灰石的形成以确定样品的生物活性。实验结果表明：不同电压制备的微弧氧化样品在模拟体液浸泡后,只有400 V和450 V的样品表面生成磷灰石层,说明高电压制备的样品具有生物活性;而低电压制备的微弧氧化样品在模拟体液中浸泡长达50 d仍未见到任何物质沉积,表明其不具有生物活性。分析认为,粗糙多孔的表面虽有利于磷灰石的成核,但高电压下出现的CaTiO_3相及其水解吸引钙、磷沉积才是磷灰石形成的主要原因。     

沉淀法制备硅酸钙及其体外生物活性的研究

采用沉淀法制备的硅酸钙粉体经成型,在1200℃下常压烧结,制备出高纯的硅酸钙陶瓷,通过模拟体液浸泡对其体外生物活性进行了研究。X射线衍射(XRD)和扫描电镜(SEM)的结果表明:在1200℃下烧结制得的硅酸钙陶瓷主晶相为β型硅酸钙(-βCS);在模拟体液中浸泡14d后其表面可见类骨羟基磷灰石生成,28d后生成大量羟基磷灰石。因此,沉淀法合成的硅酸钙具有良好的诱导类骨羟基磷灰石形成能力和体外生物活性。     

α-磷酸三钙对磷酸镁骨水泥强度与体外降解性能的影响

为探究α-磷酸三钙(α-TCP)对MPC强度和体外降解性能的影响,将α-TCP与MPC复合制得α-TCP/MPC骨水泥样品,然后将样品分别置于去离子水、模拟体液(SBF)及磷酸盐缓冲溶液(PBS)中浸泡不同周期,通过万能实验机、X射线衍射(XRD)、扫描电子显微镜(SEM)等对α-TCP/MPC骨水泥样品进行测试.结果表明,α-TCP的加入仍可保持MPC优异的力学性能,同时可提高MPC的耐水性,延缓MPC在SBF中的降解速率;SBF浸泡后的α-TCP/MPC样品表面有球状类骨磷灰石生成,表明α-TCP/MPC可能具有良好生物活性.     

多孔钛支架表面羟基磷灰石的仿生生长

以纯钛粉为原料,采用选区激光烧结(SLS)技术制备不同孔隙率仿生人工骨试样。测试烧结试样表面抗压强度,将试样表面处理后,在4倍模拟体液(SBF)中浸泡,利用X射线衍射、扫描电子显微镜和能谱分析表面涂层的物相组成,观察多孔试样的表面、纵切面及孔内涂层形貌,计算表面涂层的钙磷比。讨论了激光扫描速率和扫描间距对试样孔隙率的影响。结果表明:SLS可以获得内部连通微孔结构的试样。经过4倍模拟体液中浸泡8 d,在2组试样外表面及孔内均产生类骨磷灰石涂层,实现了HA钙磷涂层的三维生长。孔隙率较高的试样抗压强度为117 MPa,其表面诱导羟基磷灰石沉积的能力更强,且表面涂层的钙磷比与自然骨更接近,涂层的综合性能更好。     

预钙化加速类骨磷灰石在镍钛合金表面生长的电化学阻抗谱

通过酸碱处理活化NiTi合金表面,在模拟体液中仿生生长类骨磷灰石层以改善其生物相容性.采用电化学阻抗谱研究了预钙化对加速磷灰石沉积的影响,并基于双层模型建立了电子等效电路.结果表明:随着在模拟体液中浸泡时间的延长,化学处理的NiTi合金表面类骨磷灰石不断生长,并且添加预钙化试样浸泡3 d,即可在合金表面生长出均匀完整的类骨磷灰石层,而未预钙化试样表面沉积物稀少.对应电子等效电路中,预钙化试样电阻值明显大于未预钙化试样的,显示预钙化促进了活化NiTi合金表面类骨磷灰石的生长.     

碳酸根替代对磷灰石块体和涂层生物矿化的影响研究

应用体外实验方法(in vitro)研究了不同碳酸根替代量的磷灰石块体和电泳沉积涂层的生物矿化性能,通过XRD和SEM等手段分别研究了块体和电泳涂层样品的生物矿化过程.研究结果表明,碳酸根掺杂形成的磷灰石结晶程度差、晶粒尺寸小,利于块体的烧结致密及在SBF溶液中表面类骨碳酸羟基磷灰石矿化层(HCA)的形成.然而,碳酸根掺杂大大减少了涂层中气孔孔径和孔隙率,不利于矿化层的沉积生长,削弱了涂层的生物矿化性能.     

Preparation and characterisation of porous composite biomaterials based on silicon nitride and bioglass

The combination of bioinert and bioactive material offers new potentialities in bone tissue engineering. The present paper deals with preparation of novel biomaterial composite based on silicon nitride (Si₃N₄) and bioglass (in amount of 10 and 30 wt%) by free sintering at 980 °C for 1 h in nitrogen atmosphere. The obtained material was characterised by differential thermal analysis (DTA) and X-ray powder diffraction (XRD), porosity and pore size distribution were evaluated by means of mercury intrusion porosimetry (MIP). The bioactivity was examined in vitro with respect to the ability of hydroxyapatite layer formation on the surface of materials as a result of contact with simulated body fluid (SBF). All composites were studied by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) before and after immersion in SBF. The bioglass-free sample was prepared as a reference material to compare the microstructure and bioactivity to the composites.     

Effect of silicon carbide dispersion on the microwave absorbing properties of silicon carbide-epoxy composites in 2–40 GHz

In this study, silicon carbide powders were manufactured successfully by the method of preheating combustion synthesis in nitrogen atmosphere where it was introduced into an epoxy resin to produce a microwave absorber. The structure of the silicon carbide was characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Composite based on the various loadings of silicon carbide and epoxy resin specimens were prepared and the reflection losses of these composite samples were studied using the free space method. Based on the microwave measurements, microwave absorber specimens of silicon carbide with thermal plastic resin at frequencies between 2 and 18 and 18–40 GHz could be obtained from a matching thickness of 2.0 mm by controlling the content of silicon carbide.     

Fabrication and In Vitro Bioactivity of Poly (ϵ-caprolactone) Composites Filled with Silane-Modified Nano-Apatite Particles

Silane coupling agents were firstly employed to modify the surfaces of nano-apatite (n-HA) particles, and then thin films of the silanized n-HA/PCL composites were successfully developed by incorporating solvent dispersion and thermal co-blending with hot-pressing methods. In vitro studies were conducted using the 2-time simulated body fluid (2SBF). Composite specimens were soaked in 2SBF from 3 to 14. Results showed that a layer of bone-like apatite was formed within 7 days on the surfaces of all composites, after its immersion in 2SBF, demonstrating moderate in vitro bioactivity of these composites.     

Manufacturing of silicon – Bioactive glass scaffolds by selective laser melting for bone tissue engineering

The irruption of additive manufacturing techniques opens the possibility to develop three-dimensional structures with complex geometries and high precision. In the current investigation a newly designed composite combining silicon (30, 40 and 50 wt%) with a bioactive glass and printed into scaffolds was obtained, using a direct selective laser melting (SLM) approach for the first time. Samples were computer-aided designed (CAD) to have cylindrical pores of 400 μm in diameter in order to be used as biomaterials for bone replacement. X – Ray diffraction was used to characterize the appearance of a new phase of pseudowollastonite precipitated by the partial devitrification of the glassy phase after the incidence of laser radiation. The mechanical behaviour of each composition was studied trough stress-strain curves, obtaining higher values of compressive strength as the silicon content increases. Scanning electron microscopy coupled to energy dispersive X – Ray spectroscopy (SEM-EDS) and Raman spectroscopy were used to study the bioactivity of each composite after soaking in the simulated body fluid (SBF) for 7 days, confirming this behaviour.     

Effect of carbonate content on the in vitro bioactivity of carbonated hydroxyapatite

The effect of carbonate content on the apatite-forming ability of carbonated hydroxyapatite (CHA) in simulated body fluid (SBF) has been investigated. Five different nanocrystalline B-type CHA with carbonate content ranged from 2.01 to 5.25 wt% were prepared, sintered, and assessed for their in vitro bioactivity in SBF solution for 7-weeks under static conditions at 36.5 °C. The formation of the apatite layer and the surface morphology of CHA were examined by using a scanning electron microscope (FESEM) at week 1, 3, and 7 of SBF immersion, respectively. The Ca/P molar ratio of the CHA was determined by X-ray fluorescence (XRF). In addition, the sample weight changes and the pH of the SBF solution were measured. The results show that the formation of apatite layer depends on the carbonate content of CHA. Increasing the carbonate content caused significant increases in the surface area of CHA and the rate of apatite formation. Weight loss was observed for all CHA samples during the first week of SBF immersion, and thereafter followed by weight regain weekly until week 7. The changes in the pH of SBF and the Ca/P molar ratio were proportional to the carbonate content of CHA. This study thus highlights the importance of determining carbonate content aspect that govern the bioactivity of CHA.     

Hydrolysis of α-Tricalcium Phosphate in Simulated Body Fluid and Dehydration Behavior During the Drying Process

The hydrolysis of α-tricalcium phosphate (α-TCP) in a simulated body fluid (SBF) at 37°C was investigated. The hydration rate was found to be slower in SBF than that in deionized water. The concentration of ions in SBF was monitored by ICP. The hydrolysis product, which was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infra red, and X-ray photoelectron spectroscopy, was determined to be carbonate-containing, calcium-deficient hydroxyapatite (CO₃−CDHAp) with Mg²⁺, Na⁺, and Cl⁻ impurities similar to the biological apatite. An amorphous layer on the α-TCP surface was found to be the precursor of the apatite phase, which may either form crystalline apatite or may decompose back to α-TCP at a lower temperature.     

在改性模拟体液中电沉积羟基磷灰石涂层

Hydroxyapatite coatings were directly prepared on anodized titanium by electro-deposition method in a modified simulated body fluid. The configuration, structure and bioactivity of the coating were investigated with scanning electron microscopy (SEM), X-ray diffraction analyzer (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. The results demonstrated that pure and homogeneous hydroxyapatite coating can be obtained without any post-treatment. The prepared coating showed good bioactivity in simulated body fluid (SBF). The time required for a fully covered dense hydroxyapatite coatings was 4 days immersion in SBF.     

以葡萄糖为造孔剂制备多孔羟基磷灰石涂层

采用电泳沉积方法在钛基材表面制得羟基磷灰石(hydroxyapatite,HA)/葡萄糖复合涂层,经烧结处理得到多孔HA涂层。采用红外光谱仪、扫描电镜、X射线衍射和热重分析表征了涂层的组成、表面形貌、物相组成及热稳定性,黏结-拉伸实验测定涂层与基体的结合强度,人体模拟体液(simulated body fluid,SBF)浸泡测定涂层的生物亲合性。结果表明:经700℃烧结处理,复合涂层中的葡萄糖微粒热分解得到多孔HA涂层,孔径为2～20μm,涂层与基体的结合强度可达17.6MPa;在1.5倍SBF(各离子浓度为SBF的1.5倍)中浸泡5d后,多孔HA涂层表面碳磷灰石化,呈现良好的生物亲合性。     

The effect of surface treatment on CaP deposition of Ti6Al4V open cell foams in SBF solution

The effects of alkali and nitric acid surface treatment and acid etching on the CaP deposition of an open cell Ti6Al4V foam (60% porous and 300–500 μm in pore size) developed for biomedical applications were investigated in a simulated body fluid (SBF) solution for 14-day. The surface roughness of the foam specimens ground flat surfaces was measured in nano-metric scale before and after SBF immersion using an atomic force microscope (AFM). A significant increase in the surface roughness of alkali treated foam specimen after SBF immersion indicated a smaller crystal size CaP deposition, which was also confirmed by the AFM micrographs. The microscopic evaluation clearly showed that alkali treatment and nitric acid treatment induced a continuous, uniform CaP deposition on the cell wall surfaces of the foam (interior of cells). While in untreated foam specimen the cells are filled with CaP precipitates and acid etching did not produce a continuous coating layer on particles interior of the cells. The coating layer thickness was ～3 μm in alkali treated foam specimens after 14-day of SBF immersion, while nitric acid treatment induced relatively thinner coating layer, 0.6 μm.     

Spectroscopic investigation of synergetic bioactivity behavior of some ternary borate glasses containing fluoride anions

Ternary borate glasses containing LiF, ZnF₂, NaF or CaF₂ were prepared by full replacement of silica by borate in patented Hench′s bioglass. Prepared samples were examined for their corrosion behavior with the expected final formation of fluoroapatite after immersion in SBF (simulated body fluid). Characterization of the glasses was carried by FTIR (Fourier transform infrared) absorption spectra before and after immersion. DAT (deconvolution analysis technique) was used to identify the formation of fluoroxyapatite from FTIR data after immersion in SBF. X-ray diffraction analyses were done for all samples to identify the crystalline phases that were formed after immersion in SBF and also to determine the degree of crystallinity for each sample. Also, scanning electron microscopic (SEM) investigations were carried out to examine the morphological changes of the surfaces upon immersion and the effects of different individual fluoride additives. The solubility testing for glassy samples was performed and the changes in the pH of the leaching solution were measured and evaluated.