胶原/HA复合涂层多孔钛的细胞响应行为

为提高医用多孔钛的表面活性及生物相容性,以纤维烧结多孔钛为载体,采用碱热处理+模拟体液等化学方法进行羟基磷灰石(HA)沉积,随后进行水溶性胶原涂覆,制备具有三维贯通孔结构的胶原/HA复合涂层多孔钛。研究了胶原/HA复合涂层的表面形貌及化学成分,探讨复合涂层的形成机理;进行体外细胞毒性实验并分析了多孔钛表面细胞响应行为。结果表明,胶原/HA复合涂层在钛纤维表面均匀附着,胶原的填充连接可修复HA涂层表面的微裂纹,有利于小鼠前成骨细胞的黏附、增殖及分化,促进细胞的孔内跨纤维生长。胶原/HA复合涂层可以得到更好的细胞响应,对于促进早期骨与植入体的固定有很大的潜力。     

羟基磷灰石/壳聚糖复合层的制备及其结合力、润湿性研究

通过微弧氧化处理,在Ti植入体表面制备了兼具花瓣和多孔形貌的羟基磷灰石(HA)涂层,而后通过浸渍-提拉法又在HA表面成功装载了不同浓度的壳聚糖(CS)。对所得复合层进行SEM、EDS、XRD检测,探究负载CS前后复合层的的形貌、组成及物相变化;通过FT-IR分析复合层所含官能团及HA/CS界面的相互作用;并对不同HA/CS样品进行接触角测试,探究不同CS浓度对样品表面润湿性的影响;通过划痕法测试CS与HA的界面结合强度。结果表明,随着CS浓度增大,可逐渐遮盖HA层的花瓣、多孔形貌特征,使得钛表面形成光滑、连续的CS膜层;HA和CS之间有一定的键合作用,界面结合力可达8.3N;CS的负载可有效降低HA层的表面润湿性,且随着CS浓度增大,表面润湿性不断降低。     

钛涂覆多孔羟基磷灰石涂层的制备及其生物活性

在纯钛基体表面通过电泳沉积的方法制得壳聚糖/羟基磷灰石(CS/HA)复合涂层, 然后将复合涂层烧结形成多孔HA涂层。采用SEM对多孔HA涂层的形貌进行观察, XRD分析涂层的物相组成, 粘结拉伸实验测定涂层与基体的结合强度, 1.5倍人体模拟体液(1.5SBF)浸泡测定涂层的生物活性。结果表明: 当悬浮液中CS与HA质量比为1∶1时, 制得的CS/HA复合涂层经过700℃烧结处理, 涂层中CS热分解致孔形成多孔HA涂层, 孔径在10~25 μm, 涂层与基体的结合强度可达19.5 MPa; 在1.5SBF中浸泡5天后, 多孔HA涂层表面完全碳磷灰石化, 呈现较好的生物活性。      

微弧氧化和碱处理对钛的细胞粘附和骨植入行为的影响研究

考察了微弧氧化处理和碱处理对钛表面形貌、涂层成分、羟基磷灰石沉积能力、细胞黏附、骨内植入的影响。结果表明,微弧氧化和碱复合处理后的钛表面TiO2薄膜呈现大量裂缝,表现出表面含大量OH-极性基团的纳米多孔网状结构,此微观结构和组成使材料诱导羟基磷灰石生成能力显著,利于成骨细胞黏附及繁殖,无细胞毒性,细胞兼容性好。通过植入兔股骨4和12周体内动物实验组织学切片表明,材料无毒、无刺激性,与周围组织间有良好的组织相容性,该材料植入动物骨环境中可刺激成骨,具有骨传导作用。相比下,微弧氧化和碱复合处理样品的生物相容性较为优异。     

泡沫复制法制备多孔钛及表面水热碱处理改性

采用聚氨酯泡沫复制法成功的制备出孔径可控、孔隙率高且三维贯通的多孔钛.采用水热碱处理法对多孔钛进行表面改性,以提高其生物活性.改性后多孔钛的表面形貌发生了改变,呈均匀分布的三维网状微纳米结构.将改性后的多孔钛浸泡在SCPS中检测其矿化能力.研究结果表明,改性后的多孔钛能加速磷灰石的矿化,其中三维网状微纳米结构是加速矿化的主要因素.同时考察了改性后的多孔钛表面大鼠颅盖骨成骨细胞(MC3T3-E1)的黏附铺展情况.细胞培养表明细胞在改性后的多孔钛表面能较好的黏附铺展.上述研究结果表明水热碱处理改性后的多孔钛具有较好的生物活性及生物相容性.     

钛网表面含hBMP-2的复合涂层制备及hBMP-2的释放研究

为提高骨接合钛网的骨整合性和生物活性, 本研究采用碱热处理法在钛网表面构建出具有多孔结构的钛酸盐纳米纤维, 利用电化学沉积技术在钛酸盐纳米纤维表面制备磷酸钙涂层, 并采用不同方法将人骨形态发生蛋白(hBMP-2)引入涂层, 制备了三种含hBMP-2分子的复合涂层(TmhB、TmHedhB和TmHhBed)。实验对各复合涂层的表面形貌、化学成分、相组成和hBMP-2的含量与释放性能进行了表征。研究发现: 各涂层都具有多孔纤维结构, TmHedhB和TmHhBed中的磷酸钙相为羟基磷灰石(HA), 呈“串珠”状包裹在钛酸盐纳米纤维表面, “串珠”状HA的引入促进了复合涂层对hBMP-2的吸附。电化学共沉积技术在钛酸盐纳米纤维表面制备的HA/hBMP-2复合涂层中hBMP-2的含量最大, 达886 ng/mg, 在6~48 h内具有明显的hBMP-2缓释性能。     

热处理对羟基磷灰石涂层相组成、表面形貌与结合强度的影响

羟基磷灰石(HA)涂层的喷涂及其后处理工艺对其组织结构和结合强度具有重要影响.比较了热处理对不同粒度HA涂层相组成、表面形貌与结合强度的影响,为该类涂层制备工艺的优化提供实验依据.采用等离子喷涂法在纯钛表面制备了不同粒度的HA涂层,对其进行650℃不同保温时间的后热处理.利用X射线衍射仪、扫描电子显微镜和电子拉伸机检测了涂层的相组成、表面与断口形貌及剪切结合强度等.结果表明,涂层经650℃保温0.5h热处理后,非晶相和分解相基本全部转变为结晶HA.经热处理晶化后,涂层表面生成300nm以下的微粒子,双重涂层BC表面更易形成.粗粉末涂层CC和BC热处理后的剪切强度提高,而细粉末涂层FC则相反;HA涂层的剪切断裂主要是发生在涂层与基体间的界面上.     

壳聚糖/羟基磷灰石表面修饰聚己内酯多孔骨支架的制备及性能

采用选择性激光烧结技术构建多孔聚己内酯(PCL)骨支架,用原位合成的方法制得壳聚糖/羟基磷灰石(CS/HA)悬浮液,并采用真空浸泡、低速离心和冷冻凝胶的方法使CS/HA黏附在PCL支架的表面,以改善骨支架的生物相容性和细胞增殖活性。通过X射线衍射(XRD)和扫描电子显微镜(SEM)观测复合支架的物相和形貌,测量支架的压缩强度和杨氏模量,测量支架表面的水接触角,并通过体外细胞实验研究复合支架的生物学性能。实验结果表明,原位合成的方法制得了羟基磷灰石(HA);CS/HA凝胶与PCL骨支架表面黏附良好;CS/HA改善了PCL支架表面的亲水性,提升了骨支架的生物相容性和细胞增殖活性。     

壳聚糖/单宁酸复合胶体粒子的制备及功能涂层研究

以壳聚糖(Chitosan,CS)和单宁酸(Tannic acid,TA)为组装基元,在水溶液中通过pH诱导组装制备壳聚糖/单宁酸(CS/TA)复合胶体粒子,用透射电子显微镜(TEM)对复合胶体粒子的尺寸及形貌进行了表征。再将复合胶体粒子水分散液为电泳沉积液,通过电泳沉积技术诱导复合胶体粒子在316L不锈钢表面二次组装制备纳米功能涂层;利用接触角测试对涂层表面的亲疏水性进行了研究;并通过体外细胞实验探究了涂层的细胞相容性,抗菌实验测试了涂层对金黄色葡萄球菌和大肠杆菌的抗菌活性。研究结果表明,通过电诱导胶体粒子可以在316L不锈钢表面形成了致密的纳米涂层材料,涂层具有良好的细胞相容性和抗菌作用,在生物涂层领域有着潜在应用前景。     

磁控溅射纳米银含量对钛种植体抗菌性的影响

纯钛因具有优良的生物相容性，被广泛应用于口腔种植相关领域，但其本身并不具备抗菌性能，为改善钛种植体表面的抗菌性，采用磁控溅射法在钛种植体表面制备Ti-Ag纳米复合涂层，研究了涂层中纳米Ag含量对具核梭杆菌(Fusobacterium nucleatum, Fn)抗菌性能的影响。分析了样品的表面形貌、粗糙度和水接触角；对Ag⁺释放进行了检测；采用CCK-8法检测材料的细胞毒性；将各组样品与具核梭杆菌共培养，检测材料的抗菌性能。结果表明，载Ag复合涂层成功沉积在Ti片表面，并且随着纳米Ag含量的增加，样品的表面粗糙度和水接触角均增大。该Ti-Ag纳米复合涂层对小鼠L929细胞未表现出细胞毒性，符合生物安全标准。抗菌实验结果表明，随着纳米Ag含量的增加，Ag⁺释放量增加，涂层的抗菌效果也增强。可见，Ti-Ag纳米复合涂层可有效抑制Fn的生长，有望提高钛种植体的抗菌性能，为其临床运用奠定了实验基础。     

牛血清环境下等离子喷涂ZrO_2增强羟基磷灰石涂层的摩擦磨损性能

为了研究ZrO_2增强羟基磷灰石(HA)复合涂层在牛血清润滑环境下的摩擦磨损性能,首先,采用等离子喷涂技术在钛合金基体上制备了ZrO_2含量分别为0、15wt%和30wt%的HA生物陶瓷涂层;然后,分析了ZrO_2/HA复合涂层的物相成分和结合强度;最后,采用UMT-3销盘摩擦试验机研究了ZrO_2/HA复合涂层在牛血清润滑环境下的摩擦磨损性能,观察涂层磨损表面微观形貌并分析了磨损机制。结果表明:HA涂层的主要物相为HA,15wt%ZrO_2/HA复合涂层和30wt%ZrO_2/HA复合涂层中的ZrO_2以立方相形式存在,并且衍射峰强度高于HA的。随着ZrO_2含量增大,涂层的结合强度明显增大。ZrO_2/HA复合涂层与纯HA涂层相比,有更好的耐磨性和更低的摩擦系数。纯HA涂层的磨损机制以犁沟效应和磨粒磨损为主,而15wt%ZrO_2/HA复合涂层和30wt%ZrO_2/HA复合涂层的磨损机制为脆性剥落磨损。     

Nano-Ag-loaded hydroxyapatite coatings on titanium surfaces by electrochemical deposition

Hydroxyapatite (HA) coatings on titanium (Ti) substrates have attracted much attention owing to the combination of good mechanical properties of Ti and superior biocompatibility of HA. Incorporating silver (Ag) into HA coatings is an effective method to impart the coatings with antibacterial properties. However, the uniform distribution of Ag is still a challenge and Ag particles in the coatings are easy to agglomerate, which in turn affects the applications of the coatings. In this study, we employed pulsed electrochemical deposition to co-deposit HA and Ag simultaneously, which realized the uniform distribution of Ag particles in the coatings. This method was based on the use of a well-designed electrolyte containing Ag ions, calcium ions and l-cysteine, in which cysteine acted as the coordination agent to stabilize Ag ions. The antibacterial and cell culture tests were used to evaluate the antibacterial properties and biocompatibility of HA/Ag composite coatings, respectively. The results indicated the as-prepared coatings had good antibacterial properties and biocompatibility. However, an appropriate silver content should be chosen to balance the biocompatibility and antibacterial properties. Heat treatments promoted the adhesive strength and enhanced the biocompatibility without sacrificing the antibacterial properties of the HA/Ag coatings. In summary, this study provided an alternative method to prepare bioactive surfaces with bactericidal ability for biomedical devices.     

Preparation of HA/chitosan composite coatings on alkali treated titanium surfaces through sol-gel techniques

In this paper we demonstrated for the first time the feasibility to generate well crystallized hydroxyapatite/chitosan (HA/CS) composite coatings on alkali treated titanium surfaces through combining the in situ hydrothermal precipitation and sol-gel dip coating technique without introducing any other coupling agent. Alkali treatment converting hydrophobic Ti surfaces into super-hydrophilic surfaces was the pre-requirement of uniform coatings. Preliminary cell culturing results revealed that the coatings were biocompatible and supported osteoblasts attachment.     

两步电沉积法制备HA-Ti/HA复合涂层的研究

为了提高金属基羟基磷灰石（HA）涂层的结合强度,采用复合电沉积一电沉积两步法在含Ti粉的钙磷电解液中制备HA—Ti／HA复合涂层,对涂层的组分结构、表面形貌、热稳定性、结合强度和生物活性进行了研究．实验结果表明：两步法制备的底层为HA—Ti复合涂层,外层为纯HA涂层的HA—Ti／HA复合涂层既提高了涂层的结合强度,又保证了涂层的生物活性．当涂层中Ti粉的质量分数为51．2wt％时,涂层与基体的结合强度达到21．2MPa,约为纯HA涂层的3倍．模拟体液浸泡7天后,涂层表面即被一层球状碳磷灰石覆盖,具有良好的生物活性,与纯HA涂层相比,复合涂层具有更好的耐蚀性能．     

Bioactive nanocomposite coatings of collagen/hydroxyapatite on titanium substrates

Collagen/hydroxyapatite (HA) nanocomposite thin films containing 10, 20, and 30 wt.% HA were prepared on commercially pure titanium substrates by the spin coating of their homogeneous sols. All of the nanocomposite coatings having a thickness of ∼7.5 μm exhibited a uniform and dense surface, without any obvious aggregation of the HA particles. A minimum contact angle of 36.5° was obtained at 20 wt.% HA, suggesting that these coatings would exhibit the best hydrophilicity. The in vitro cellular assays revealed that the coating treatment of the Ti substrates favored the adhesion of osteoblast-like cells and significantly enhanced the cell proliferation rate. The cells on the nanocomposite coatings expressed much higher alkaline phosphatase (ALP) levels than those on the uncoated Ti substrates. Increasing the amount of HA resulted in a gradual improvement in the ALP activity. The nanocomposite coatings on Ti substrates also exhibited much better cell proliferation behaviors and osteogenic potentials than the conventional composite coatings with equivalent compositions, demonstrating the greater potential of the former as implant materials for hard tissue engineering.     

Hydrothermal-electrochemical codeposited hydoxyapatite/yttria-stabilized zirconia composite coating

Hydroxyapatite(HA)/yttria-stabilized zirconia(YSZ) composite coatings were deposited on titanium substrates using a hydrothermal electrochemical method in an electrolyte containing calcium, phosphate ions and YSZ particles. HA/YSZ composite coatings were prepared in different conditions with different electrolyte temperatures(100 ∼ 200°C), current densities(0.1 ∼ 10.0 mA/cm²), and particles content in bath(0 ∼ 100 g/L). The effect of YSZ additions on the phase composition, microstructure, thermal stability, corrosion behavior and the bonding strength of HA/YSZ composite coatings were studied. The results show that crystallinity of HA in HA/YSZ composite coatings increase continuously with the electrolyte temperature and close to stoichiometric HA. The n(Ca)/n(P) ratio at 200°C is about 1.67 according with stoichiometric HA. YSZ particles are imbedded uniformly between the HA crystals. The average HA crystal size are reduced owing to the additions of YSZ particles. After annealing at 1200°C, tetragonal phase YSZ tend to react with the released CaO to form cubic phase YSZ and CaZrO₃, which cause destabilization of HA to decompose into more α-TCP phase. The bonding strength between HA/YSZ composite coatings and titanium substrates increase with increasing volume content of YSZ in the composite coatings (V %). HA/YSZ composite coatings exhibit a better electrochemical behavior than pure HA coatings and uncoated Ti metals.     

Electrospun chitosan/hydroxyapatite nanofibers for bone tissue engineering

Chitosan (CS) nanofibers were prepared by an electrospinning technique and then treated with simulated body fluid (SBF) to encourage hydroxyapatite (HA) formation on their surface. The CS/HA nanofibers were subjected to scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy, and X-ray diffraction (XRD) to confirm HA formation as well as determine the morphology of the nanofibrous scaffolds. The SEM image indicated that the distribution of HA on the CS nanofibers was homogeneous. The results from EDS and XRD indicated that HA was formed on the nanofibrous surfaces after 6-day incubation in the SBF. The calcium/phosphorus ratio of deposited HA was close to that of natural bone. To determine biocompatibility, the CS/HA scaffolds were applied to the culture of rat osteosarcoma cell lines (UMR-106). The cell densities on the CS/HA nanofibers were higher than those on the CS nanofibers, the CS/HA film, and the CS film, indicating that cell proliferation on CS/HA nanofibers was enhanced. Moreover, the early osteogenic differentiation on CS/HA was also more significant, due to the differences in chemical composition and the surface area of CS/HA nanofibers. The biocompatibility and the cell affinity were enhanced using the CS/HA nanofibers. This indicates that electrospun CS/HA scaffolds would be a potential material in bone tissue engineering.     

Surface Modification of Biomaterials in Hard Tissue Applications

Surface modification technologies are quite common in the biomedical field to improve the mechanical,chemical, physical and biological properties of implants such as artificial joint and cardiovascular devices. In this paper, recent progress in the investigation of the bioactivity and biocompatibility enhancement of implants using plasma spraying and plasmabased ion implantation (PIII) is described. Plasma sprayed hydroxyapatite (HA) coatings are commonly used as bioactive coatings but the relatively poor adhesion between the coatings and titanium is one of main disadvantages which have limited their biomedical applications. In our recent studies, novel bioactive coatings, such as wollastonite and dicalcium silicate, were deposited onto titanium to enhance the surfaces bioactivity and biocompatibility. Our results indicate that plasma sprayed wollastonite and dicalcium silicate coatings possess excellent bioactivity as well as relatively high bonding strength. Plasma immersion ion implantation was also employed to improve the anti-corrosion and biological properties of implants.     

Surface microstructure and cell biocompatibility of silicon-substituted hydroxyapatite coating on titanium substrate prepared by a biomimetic process

Silicon-substituted hydroxyapatite (Si-HA) coatings with 0.14 to 1.14 at.% Si on pure titanium were prepared by a biomimetic process. The microstructure characterization and the cell compatibility of the Si-HA coatings were studied in comparison with that of hydroxyapatite (HA) coating prepared in the same way. The prepared Si-HA coatings and HA coating were only partially crystallized or in nano-scaled crystals. The introduction of Si element in HA significantly reduced P and Ca content, but densified the coating. The atom ratio of Ca to (P + Si) in the Si-HA coatings was in a range of 1.61–1.73, increasing slightly with an increase in the Si content. FTIR results displayed that Si entered HA in a form of SiO₄ unit by substituting for PO₄ unit. The cell attachment test showed that the HA and Si-HA coatings exhibited better cell response than the uncoated titanium, but no difference was observed in the cell response between the HA coating and the Si-HA coatings. Both the HA coating and the Si-HA coatings demonstrated a significantly higher cell growth rate than the uncoated pure titanium (p < 0.05) in all incubation periods while the Si-HA coating exhibited a significantly higher cell growth rate than the HA coating (p < 0.05). Si-HA with 0.42 at.% Si presented the best cell biocompatibility in all of the incubation periods. It was suggested that the synthesis mode of HA and Si-HA coatings in a simulated body environment in the biomimetic process contribute significantly to good cell biocompatibility.     

等离子喷涂HA／Ti复合涂层研究

对等离子喷涂HA／Ti复合涂层进行模拟体液和体外细胞试验,以考察涂层的生物学性能．结果指出,涂层经模拟体液浸泡后,表面覆盖一层碳酸磷灰石(carbonate-apatite),这表明涂层具有良好的生物活性．粗糙的涂层表面易于形成碳酸磷灰石．模拟体液的浓度太小或pH值太大,均会导致碳酸磷灰石层不能在涂层表面形成．体外细胞试验显示,成骨细胞能在涂层表面紧密贴壁并正常生长,显示涂层具有优良的生物相容性．