新工艺制备纳米钛酸钙涂层及生物相容性评价

目的 :研究新型纳米钛酸钙(CaTiO_3)涂层钛合金材料的生物相容性。方法 :将钛板、羟基磷灰石涂层钛板和纳米CaTiO_3涂层钛板分为钛板组、涂层组、纳米组(各60例)。通过扫描电镜、X射线衍射对3组材料进行分析。将各组材料与成骨细胞(MC3T3-E1)共培养,通过免疫荧光染色、MTT法、碱性磷酸酶(ALP)含量测定评估材料表面细胞的存活、增殖及分化情况;通过电镜检测材料表面成骨细胞的钙化。结果 :涂层组、纳米组比钛板组有更高的活细胞数量、MTT值、ALP含量,有更好的细胞结构形态和钙化,而涂层组、纳米组无差异。结论 :该新型纳米CaTiO_3涂层材料有良好的生物相容性,为其将来临床植入体内提供了一定的实验依据。     

羟基磷灰石/TiO_2纳米管复合物的生物相容性

背景:羟基磷灰石具有优良的生物相容性,但目前缺少纳米羟基磷灰石/TiO2纳米管复合物生物相容性的相关研究。目的:分析纳米羟基磷灰石/TiO2纳米管复合物的生物相容性。方法:先通过阳极氧化技术在钛金属表面制备TiO2纳米管,后采用电沉积技术制备纳米羟基磷灰石/TiO2纳米管复合物,在扫描电镜下观察复合物的表面形貌。将纳米羟基磷灰石/TiO2纳米管复合物、TiO2纳米管形貌钛金属和商业钛金属分别与小鼠成骨细胞MC-3T3-E1共同培养,观察细胞在支架上的黏附、增殖及凋亡。结果与结论:通过改变阳极氧化条件及磁场条件能制备不同管径及管长的TiO2纳米管,以及不同形貌的纳米羟基磷灰石/TiO2纳米管复合物。倒置显微镜观察共培养3 d后,TiO2纳米管形貌钛金属及纳米羟基磷灰石/TiO2纳米管复合物周围的细胞明显增殖,细胞形态良好,排列规则,细胞增殖情况优于商业钛金属组。扫描电镜观察共培养3 d后,细胞在TiO2纳米管形貌钛金属及纳米羟基磷灰石/TiO2纳米管复合物上生长良好,可见大量细胞伪足附着于其上;纳米羟基磷灰石/TiO2纳米管复合物组的细胞凋亡率7.8%小于TiO2纳米管形貌钛金属组的9.4%及商业纯钛金属组的13.5%,表明纳米羟基磷灰石/TiO2纳米管具有良好的生物相容性。     

纯钛表面载阿司匹林微球与聚多巴胺复合涂层促进成骨分化北大核心

背景:钛作为骨替代材料已在口腔种植领域中得到广泛应用,但其生物惰性会影响植入早期与骨组织形成稳定的结合,因此探索通过表面改性来提高钛的成骨活性是很有必要的。目的:探讨钛表面载阿司匹林的壳聚糖微球与聚多巴胺复合涂层对体外成骨细胞活性的影响。方法:取纯钛片,表面分别构建聚多巴胺涂层和载阿司匹林的壳聚糖微球与聚多巴胺复合涂层,采用扫描电镜和接触角检测对改性前后钛片的表面微观形貌和亲水性进行表征,检测纯钛表面阿司匹林纳米微球涂层的体外缓释性能。将大鼠骨髓间充质干细胞分别接种于纯钛片与两种改性钛片上培养,采用细胞骨架染色观察钛片表面细胞的铺展形态,CCK-8实验测定细胞的增殖活性,碱性磷酸酶染色和免疫荧光染色评估钛片表面细胞的成骨分化能力。结果与结论:①扫描电镜显示,纯钛表面相对光滑,聚多巴胺改性后出现沉积物及颗粒状突起,阿司匹林微球呈圆球形且粒径分布均匀;聚多巴胺涂层组与阿司匹林微球涂层组钛片的亲水性均明显优于纯钛组(P<0.05);阿司匹林在微球的包裹下呈现缓慢持续释放;②细胞骨架染色显示,纯钛表面的细胞伸展不充分,聚多巴胺涂层组钛片表面的细胞伸出少量伪足,阿司匹林微球涂层组钛片表面的细胞伸展良好;③CCK-8实验结果显示,3组钛片均无明显细胞毒性,且随着细胞培养时间的延长,阿司匹林微球涂层组钛片表面的细胞增殖速率高于其他两组(P<0.05);④阿司匹林微球涂层组钛片表面细胞的碱性磷酸酶活性最高,免疫荧光显示该组细胞中成骨相关蛋白碱性磷酸酶的荧光强度最强;⑤结果表明,纯钛表面载阿司匹林的壳聚糖微球缓释涂层可以增强大鼠骨髓间充质干细胞的增殖和黏附,并促进其成骨向分化。     

羟基磷灰石表面修饰人工角膜钛支架的生物相容性:电镜观察

背景:人工角膜是双眼角膜盲患者复明的希望,提高人工角膜材料的生物相容性使人工角膜与宿主角膜达到生物愈合是目前人工角膜的研究方向。目的:扫描电子显微镜观察经羟基磷灰石表面修饰能否增加人工角膜纯钛支架的生物相容性。方法:采用酸碱两步预处理法在人工角膜钛支架表面快速沉积羟基磷灰石涂层。将第4～6代兔角膜基质成纤维细胞直接接种于羟基磷灰石修饰的钛支架、纯钛支架及玻璃表面,3,24,48,72h后,扫描电子显微镜观察材料表面的细胞黏附,伸展及增殖情况;将18只正常新西兰白兔随机分为2组,于右眼角膜基质层内分别植入羟基磷灰石修饰的钛支架、纯钛支架,术后6,12周取出人工角膜支架,扫描电子显微镜观察材料表面角膜组织贴附生长状态。结果与结论:体外实验显示,细胞接种3h和24h后,细胞扩展面积及细胞张力丝长度:羟基磷灰石修饰的钛支架玻璃纯钛表面,羟基磷灰石修饰的钛支架表面的活细胞数多于其他材料表面(P0.05)。72h后,羟基磷灰石修饰的钛支架表面完全被胶原覆盖。体内实验显示,扫描电子显微镜观察羟基磷灰石修饰的钛支架表面细胞外基质生长良好,与羟基磷灰石贴附紧密。而纯钛支架仅为角膜组织简单包裹。说明人工角膜纯钛支架经羟基磷灰石表面修饰后,其生物相容性增加。     

纯钛表面阳极氧化增强成骨细胞生物活性及护骨素基因的表达

背景:纯钛阳极氧化改性后形成的纳米结构与骨组织具有良好的生物相容性。目的:观察纯钛表面纳米孔结构的形貌和物相构成,以及其对MC3T3-E1小鼠前成骨细胞增殖、黏附等生物学行为和促成骨基因护骨素表达的影响。方法:取纯钛片24份,其中12份仅进行机械抛光,作为对照组;另外12份进行机械抛光后,应用阳极氧化技术在纯钛表面制备纳米孔结构,作为实验组。将小鼠前成骨细胞MC3T3-E1分别接种于两组试件表面,接种7 d后扫描电镜下观察细胞形态,采用MTT法检测细胞增殖情况,绘制生长曲线;同时检测细胞促成骨基因护骨素的表达。结果与结论:阳极氧化后钛片表面形成规格统一的纳米孔结构,但是物相构成并未发生变化。与接种于对照组试件上的成骨细胞相比,实验组试件表面的细胞密度变大,覆盖金属的面积更多,呈现多边形结构,突触向周围移行,可见板状伪足向周围材料伸出;接种第7天时,实验组细胞数目约为对照组的1.4倍,同时纳米孔表面成骨细胞护骨素基因的表达高于对照组(P0.01)。结果表明阳极氧化后形成纳米孔结构的钛片更有利于成骨细胞的黏附、增殖和护骨素基因的表达,进而促进成骨细胞生长,具有良好的生物相容性。     

NiTi合金种植体仿生生长磷灰石涂层及其生物学研究

为赋予NiTi形状记忆合金表面具有生物活性,并探讨类骨磷灰石涂层NiTi作为人工骨修复替代材料的可行性.本研究通过酸碱处理活化NiTi合金,采用仿生方法制备羟基磷灰石涂层,在中国白兔股骨中植入,以无涂层NiTi合金为对照,在植入后15周和26周分别进行组织病理学和超微组织学测试.结果表明仿生生长磷灰石的成分和结构近似于自然骨中的矿物质,晶粒为纳米尺度,是含碳酸根及钙离子缺陷的类骨磷灰石.NiTi/HA植入兔股骨可刺激成骨细胞活跃、增殖,15周后形成完全骨接触界面,且结合状态良好无裂隙.同期NiTi植入体与骨组织间有未吸收的纤维组织,界面结合较差有裂隙.植入26周后,两种种植体与皮质骨均为骨接触.但在髓腔界面,NiTi/HA周围干细胞成骨过程基本完成,新骨紧密包裹种植体;而NiTi表面新骨层残破不全,出现裂隙.说明类骨磷灰石涂层NiTi合金是生物活性材料,有较强的成骨能力,与骨组织间为化学键合.     

钛合金表面新型生物玻璃/羟基磷灰石涂层的体内动物实验

目的为促进钛合金植入体与骨的结合,在其表面制备了生物玻璃/羟基磷灰石复合涂层,并植入兔子股骨内进行动物试验,采用等离子喷涂羟基磷灰石涂层和未涂层的Ti6Al4V合金作为对照。方法种植到期的植入体取出后进行组织学切片,采用品红-苦味酸染色后进行组织学观察,采用SEM高倍观察种植体与骨的结合界面,并对骨接触率和凹槽内骨长入量进行了统计分析和比较。结果三种植入体都具有良好的生物相容性。Ti6Al4V合金与骨之间是一种形态固定,而生物玻璃/羟基磷灰石涂层、等离子喷涂羟基磷灰石涂层可与骨形成骨键合。生物玻璃/羟基磷灰石涂层在植入期间与基体没有脱落,同时其与骨的接触率和凹槽内骨长入量要明显高于其余两个植入体,显示出促进骨生长的作用。结论由于具有良好的生物相容性和促进新骨生长的能力,生物玻璃/羟基磷灰石涂层可加快植入体与骨的愈合速度,在骨替代修复方面显示出优势和广阔的应用前景。     

钛植入体表面钽功能涂层制备及性能表征北大核心

背景:钛合金因其良好的生物相容性被广泛应用于临床骨科,但其作为生物惰性材料缺乏骨诱导活性,易导致植入假体松动,因此有必要对钛植入体表面进行改性来增强其成骨活性。目的:利用溶胶凝胶法在钛表面制备钽功能涂层,并对涂层的理化性质及成骨性能进行表征。方法:利用溶胶凝胶法在医用钛片表面制备钽功能涂层,采用扫描电镜及能谱分析对涂层的表面形貌及元素组成进行表征,通过接触角测试评估钛片、钽片、钽涂层的表面亲水性。将兔骨髓间充质干细胞分别接种于钛片、钽片、钽涂层上,利用扫描电镜观察材料表面细胞黏附形态,荧光染色观察材料表面细胞黏附及存活,CCK-8法检测细胞增殖活性,碱性磷酸酯酶显色及茜素红S染色评估材料表面细胞的成骨分化能力。结果与结论:(1)扫描电镜显示,涂层表面均匀分布着大小一致的纳米级颗粒,且表面涂层均一,未见裂纹产生;元素分析结果显示,钽涂层表面的元素主要为Ta、O、Ti元素;钽涂层表面的亲水性优于钛片、钽片;(2)接种12 h后的扫描电镜显示,细胞在钛片和钽片表面的黏附形态相似,呈长梭形,向周边伸出少量丝状伪足;细胞在钽涂层表面呈铺展态黏附生长,向远处伸出大量丝状伪足并与相邻细胞连接;(3)接种72 h后的荧光染色显示,细胞在钽涂层表面几乎均呈铺展态黏附生长,黏附细胞的数量多于钛片、钽片,并且钽涂层表面的活细胞数量多于钛片、钽片(P <0.05);(4)CCK-8法检测结果显示,钽涂层表面的细胞增殖速率快于钛片、钽片(P <0.05);(5)钽涂层表面细胞的碱性磷酸酶含量和钙结节形成数量均多于钛片、钽片;(6)结果表明,钽涂层修饰后的钛表面更利于骨髓间充质干细胞的黏附及成骨分化。     

纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥与骨髓基质细胞的生物相容性*☆

背景：在前期的试验中,通过共沉淀法合成了纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合粉体,并与柠檬酸衍生物溶液调和制备出可生物降解、适当力学性能以及较好黏合强度的骨水泥。 目的：验证纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥材料对体外兔骨髓基质细胞黏附及增殖的影响,了解材料的生物相容性。 方法：应用共沉淀法制备纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合材料作为骨水泥的固相粉体,将柠檬酸衍生物配制成溶液作为液相调和制备黏合性骨水泥。培养兔骨髓基质细胞,传代扩增后接种到材料上,体外继续培养;以细胞加入无材料的培养皿培养为对照。 结果与结论：体外培养的兔骨髓基质细胞2 d后呈梭形成纤维细胞样,生长良好。有材料实验组细胞数显著多于对照组(P < 0.01)。扫描电镜下骨水泥材料具有良好的多孔网状结构,兔骨髓基质细胞伸出多个伪足样突起,紧密贴附在材料表面。两组细胞均保持持续增殖,2,4,6,和8 d实验组增殖均显著快于对照组(P < 0.01)。提示纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥材料具有良好的生物相容性。      

等离子喷涂羟基磷灰石涂层的骨桥接性研究

羟基磷灰石 (Hydroxyapatite ,HA)涂层与宿主骨之间有一定间隙的情况下新骨能长入间隙 ,形成骨键合 ,起到桥接作用 ,在临床上具有非常重要的作用。然而 ,多大的间隙为HA涂层最大桥接距离 ,各种实验数据相差很大。本实验在纯钛基底上用等离子喷涂及水蒸汽后处理法制得结晶度为 88% ,厚约 10 0 μm的HA涂层。选用狗的股骨为实验对象 ,纯钛和HA涂层为植入体 ,植入体与宿主骨之间的间隙为 2mm。组织形貌学显示 :12周后 ,HA涂层与宿主骨之间的间隙被新骨充满 ,涂层与骨之间形成直接的骨键合 ;而纯钛植入体与宿主骨之间的间隙为纤维组织充填。     

The influence of novel bioactive glasses on in vitro osteoblast behavior

Implant success requires a direct bond between bone and implant surface. Bioinert implants, such as titanium alloys, are commonly plasma-spray-coated with a bone-bonding, bioactive material such as hydroxyapatite. Such coatings tend to be chemically and topographically inhomogeneous without reproducible properties. A family of bioactive glasses that can be enameled and reliably adheres to titanium alloy has been developed. In this study the cytocompatibility of two of these glass compositions was tested in the as-cast condition. The effects of these glasses on the early and late events of osseous tissue formation in vitro were determined with MC3T3-E1.4 mouse osteoblast-like cells. MC3T3-E1.4 cells were cultured on glasses containing 55 and 50 wt % SiO(2), with titanium alloy (Ti6Al4V) and tissue culture polystyrene as controls. Cellular adhesion and proliferation, and alkaline phosphatase activity were studied over 5 to 15 days in culture. Qualitative and quantitative assays of mineralization were conducted. The osteoblast-like cells showed increased proliferation when grown on a bioactive glass containing 50 wt % silica. However, the adhesion, differentiation and mineralization behavior were similar on both glass compositions used in this study. These bioactive glasses proved to be cytocompatible substrata for osteoblast-like cell culture, and yielded higher cellular proliferation than titanium alloy.     

Physical characterization of different-roughness titanium surfaces, with and without hydroxyapatite coating, and their effect on human osteoblast-like cells

The aim of this study was to characterize and compare various titanium (Ti) and hydroxyapatite (HA) coatings on Ti6Al4V, in view of their application on noncemented orthopedic implants. Two innovative vacuum plasma sprayed (VPS) coatings, the first of ultrahigh rough and dense Ti (PG60, Ra=74 microm) and the second of ultrahigh rough and dense Ti coated with HA (HPG60, Ra=52 microm), have been developed, and the response of osteoblast-like cells (MG-63) seeded on these new coatings was evaluated in comparison to: a low roughness and sandblasted (Ti/SA, Ra=4 microm) Ti6Al4V surface; Ti medium (TI01, Ra=18 microm), and high (TI60, Ra=40 microm) roughness VPS coatings; and the relative Ti plus HA duplex coatings (HT01, Ra=12 microm and HT60, Ra=36 microm respectively), also obtained by VPS. PG60 coating presented no open porosity, making it dense and potentially intrinsically stronger. Cell adhesion and proliferation on PG60 was similar to those of the smoothest one (Ti/SA) and adhesion on ultrahigh roughness was lower than the medium- and high-roughness coatings, whereas cell proliferation on PG60 was lower than TI60. The HA coating determined significant increases in cell proliferation at medium and high roughness levels when compared to the relative Ti coating, but not compared to the ultrahigh one; all HA-coated surfaces showed a decrease in alkaline phosphatase activity and collagen I production. Surface morphology and the HA coating strongly affected cell behavior. However, ultrahigh values of roughness are not correctly seen by cells, and the presence of HA has no improving effects.     

Peptide-modified p(AAm-co-EG/AAc) IPNs grafted to bulk titanium modulate osteoblast behavior in vitro

Interpenetrating polymer networks (IPNs) of poly(acrylamide-co-ethylene glycol/acrylic acid) (p(AAm-co-EG/AAc) applied to model surfaces prevent protein adsorption and cell adhesion. Subsequently, IPN surfaces functionalized with the RGD cell-binding domain from rat bone sialoprotein (BSP) modulated bone cell adhesion, proliferation, and matrix mineralization. The objective of this study was to utilize the same biomimetic modification strategy to produce functionally similar p(AAm-co-EG/AAc) IPNs on clinically relevant titanium surfaces. Contact angle goniometry and X-ray photoelectron spectroscopy (XPS) data were consistent with the presence of the intended surface modifications. Cellular response was gauged by challenging the surfaces with primary rat calvarial osteoblast (RCO) surfaces in serum-containing media. IPN modified titanium and negative control (RGE-IPN) surfaces inhibit cell adhesion and proliferation, while RGD-modified IPNs on titanium supported osteoblast attachment and spreading. Furthermore, the latter surfaces supported significant mineralization despite exhibiting lower levels of proliferation than positive control surfaces. These results suggest that with the appropriate optimization, this approach may be practical for surface engineering of osseous implants.     

Biocompatibility of corrosion-resistant zeolite coatings for titanium alloy biomedical implants

Titanium alloy, Ti6Al4V, is widely used in dental and orthopedic implants. Despite its excellent biocompatibility, Ti6Al4V releases toxic Al and V ions into the surrounding tissue after implantation. In addition, the elastic modulus of Ti6Al4V (～110 GPa) is significantly higher than that of bone (10–40 GPa), leading to a modulus mismatch and consequently implant loosening and deosteointegration. Zeolite coatings are proposed to prevent the release of the toxic ions into human tissue and enhance osteointegration by matching the mechanical properties of bone. Zeolite MFI coatings are successfully synthesized on commercially pure titanium and Ti6Al4V for the first time. The coating shows excellent adhesion by incorporating titanium from the substrate within the zeolite framework. Higher corrosion resistance than the bare titanium alloy is observed in 0.856 M NaCl solution at pHs of 7.0 and 1.0. Zeolite coatings eliminate the release of cytotoxic Al and V ions over a 7 day period. Pluripotent mouse embryonic stem cells show higher adhesion and cell proliferation on the three-dimensional zeolite microstructure surface compared with a two-dimensional glass surface, indicating that the zeolite coatings are highly biocompatible.     

The response of osteoblast-like cells towards collagen type I coating immobilized by p-nitrophenylchloroformate to titanium

The scaffold surface composition can be altered by the use of surface coatings. The use of thin coatings will give special surface properties, while the bulk properties of the scaffold are preserved. Collagen type I is known to play an important role during cell adhesion as well as osteoblast differentiation. A common way to coat surfaces is the adsorption method. An alternative way is the use of a protein immobilization method like p-nitrophenyl chloroformate. In this study, we investigated the effect of a collagen type I coating and p-nitrophenyl chloroformate as a protein immobilization method on osteoblast adhesion, proliferation, and differentiation. Titanium fiber meshes were treated with sodium hydroxide (NaOH), followed by p-nitrophenyl chloroformate, and coated with collagen type I. Osteoblast-like cells were seeded into the meshes and cultured for 24 days. The cell attachment, proliferation, and differentiation were measured by using Live and Dead assay, cell counting, DNA analysis, alkaline phosphatase activity assay, calcium content measurement, Real Time PCR (QPCR), and scanning electron microscopy (SEM). Results demonstrated that initially less cells were attached to the covalently bounded collagen meshes (NPC-Col) compared with titanium as control (Ti) and adsorbed collagen meshes (ABS-Col). Further, a decreased growth curve of cells cultured on the NPC-Col meshes was observed in comparison with Ti and ABS-Col meshes. The calcium measurements and SEM pictures revealed that all three surfaces showed differentiation of osteoblast-like cells after 8-24 days. On the basis of our results, we conclude that initially less cells were attached to the NPC-Col meshes and that they had a decreased proliferation rate. Further, we conclude that an adsorbed collagen type I coating stimulated the osteoblastic differentiation of rat bone marrow cells.     

纯钛种植体表面微弧氧化涂层的生物相容性

背景：各种纯钛种植体表面微弧氧化涂层效果不尽相同。 目的：观察3种不同微弧氧化涂层种植体钛片对小鼠成骨细胞的细胞增殖、碱性磷酸酶活性和β1-integrin的基因表达水平的影响。 方法：采用国际常用小鼠成骨细胞系(MC3T3-E1),3种不同涂层钛片作为影响因素,纯钛作为对照,采用MTT法和电镜法观察细胞附着和细胞增殖,PNPP法测定碱性磷酸酶的活性,RT-PCR法检测β1-integrin在小鼠成骨细胞中的表达。 结果与结论：MTT值、碱性磷酸酶值、β1-integrin的基因表达水平和电镜观察均显示含钙、磷、镁、锌元素的二氧化钛涂层钛片生物相容性最好,含钙磷盐的二氧化钛涂层钛片次之,二氧化钛涂层钛片最差。小鼠成骨细胞在其多孔,含有钙、磷、镁、锌元素表面的黏附及增殖最优。     

Titanium containing amorphous hydrogenated carbon films (a-C: H/Ti): surface analysis and evaluation of cellular reactions using bone marrow cell cultures in vitro

Amorphous hydrogenated carbon (a-C : H) coatings, also called diamond-like carbon (DLC), have many properties required for a protective coating material in biomedical applications. The purpose of this study is to evaluate a new surface coating for bone-related implants by combining the hardness and inertness of a-C : H films with the biological acceptance of titanium. For this purpose, different amounts of titanium were incorporated into a-C : H films by a combined radio frequency (rf) and magnetron sputtering set-up. The X-ray photoelectron spectroscopy (XPS) of air-exposed a-C : H/titanium (a-C : H/Ti) films revealed that the films were composed of TiO2 and TiC embedded in and connected to an a-C : H matrix. Cell culture tests using primary adult rat bone marrow cell cultures (BMC) were performed to determine effects on cell number and on osteoblast and osteoclast differentiation. By adding titanium to the carbon matrix, cellular reactions such as increased proliferation and reduced osteoclast-like cell activity could be obtained, while these reactions were not seen on pure a-C : H films and on glass control samples. In summary, a-C : H/Ti could be a valuable coating for bone implants, by supporting bone cell proliferation while reducing osteoclast-like cell activation.     

Osteoblastic cell behaviour on different titanium implant surfaces

The osseointegration of oral implants is related to the early interactions between osteoblastic cells and titanium surfaces. The behaviour of osteoblastic MC3T3-E1 cells was compared on four different titanium surfaces: mirror-polished (Smooth-Ti), alumina grit-blasted (Alumina–Ti) or biphasic calcium phosphate ceramic grit-blasted (BCP–Ti) and a commercially available implant surface (SLA). Scanning electron microscopy and profilometry showed distinct microtopographies. The BCP–Ti group had higher average surface roughness (R_a = 2.5 μm) than the other grit-blasted groups. Hydrophilicity and surfaces energies were determined on the different substrates by dynamic contact angle measurements. The most hydrophilic surface was the Alumina–Ti discs, while SLA was the most hydrophobic. The titanium surfaces were all oxidized as TiO₂ and polluted by carbon contaminants, as determined by X-ray photoelectron spectroscopy. Alumina–Ti samples also exhibited aluminium peaks as a result of the blasting. The BCP–Ti discs contained traces of calcium and phosphorus. MC3T3-E1 cells attached, spread and proliferated on the substrates. For both the SLA and BCP–Ti groups, the entire surface was covered with a layer of osteoblastic cells after 2 days. At high magnification, the cells exhibited cytoplasmic extensions and filopodia. Compared with plastic, cell viability was similar with the Smooth–Ti, slightly lower with the Alumina–Ti and superior with the SLA and BCP–Ti groups. Alkaline phosphatase activity increased with the culture time whatever the substrate. This study shows that BCP-blasting produces rough titanium implants without surface contaminants.     

High concentration of residual aluminum oxide on titanium surface inhibits extracellular matrix mineralization

In the present study we characterized titanium (Ti) surfaces submitted to different treatments and evaluated the response of osteoblasts derived from human alveolar bone to these surfaces. Five different surfaces were evaluated: ground (G), ground and chemical etched (G1-HF for 60 s), sand blasted (SB-Al(2)O(3) particles 65 mum), sand blasted and chemical etched (SLA1-HF for 60 s and SLA2-HF for 13 s). Surface morphology was evaluated under SEM and roughness parameters by contact scanning instrument. The presence of Al(2)O(3) was detected by EDS and the amount calculated by digital analyses. Osteoblasts were cultured on these surfaces and it was evaluated: cell adhesion, proliferation, and viability, alkaline phosphatase activity, total protein content, and matrix mineralization formation. Physical and chemical treatments produced very different surface morphologies. Al(2)O(3) residues were detected on SB and SLA2 surfaces. Only matrix mineralization formation was affected by different surface treatments, being increased on rough surface (SLA1) and reduced on surface with high amount of Al(2)O(3) residues (SB). On the basis of these findings, it is possible to conclude that high concentration of residual Al(2)O(3) negatively interfere with the process of matrix mineralization formation in contact with Ti implant surfaces.     

Electrochemical activation of titanium for biomimetic coating of calcium phosphate

This article reports an electrochemical method to activate titanium surface for biomimetic calcium phosphate (Ca-P) coatings. Titanium serving as cathode was treated in an electrochemical cell with a supersaturated calcium and phosphate solution serving as electrolyte. This treatment generated a gel-like film with thickness of about 100 nm on the titanium surface. The amorphous film was composed by calcium and phosphate ions and contained a large number of crystal nuclei of octacalcium phosphate (OCP). The effectiveness of this novel treatment was demonstrated by comparing the behavior of treated and untreated titanium when used for biomimetic coating. A uniform Ca-P coating was formed on the treated titanium after immersion for several hours in aqueous solution. This work explored a new method to activate surfaces of metal implants for osseointegration, which is considerably faster than treatments currently in use, such as alkaline treatment.