钛合金经酸碱两步预处理快速沉积HA涂层

目的钛合金经酸碱两步预处理后在表面快速沉积羟基磷灰石涂层。方法钛合金(Ti_6Al_4V)均分为A、B两组。A组先用砂纸打磨,再用0．6mol/L NaOH在160℃下处理24h;B组先用H_2SO_4与HCl混合酸腐蚀1h,再用0．6mol/L NaOH在160℃处理24h。两组试件各8片分别置于过饱和钙磷溶液SCS1- SCS8中24h。XRD和SEM分析涂层成分、表面和断面形貌。表面形貌仪分析沉积前样品的表面粗糙度。结果在SCS1溶液中的钛合金片表面均沉积了致密的羟基磷灰石涂层,涂层表面由片状晶体组成,涂层厚度约为30μm。结论B组样品避免了对试样的打磨,在合适的SCS溶液中同样可以快速沉积羟基磷灰石涂层。该工艺特别适合在复杂形状的样品表面沉积涂层。     

钛表面纳米仿生磷灰石涂层对成骨样细胞活性的生物增强效应

目的：观察钛表面纳米仿生磷灰石涂层对成骨样细胞行为的影响，为骨科常用钛植入体的表面改性及其生物效应提供实验依据。方法: 商业用纯钛经过物理、化学和生物处理，表面生成均匀薄层仿生的纳米磷灰石涂层，将仿生涂层的钛金属板与成骨样细胞复合培养，以纯钛和只经磨砂、酸蚀处理的钛板作为对照，采用MTT法检测细胞活力和增殖变化、扫描电镜和激光共聚焦荧光显微镜观察细胞形态、RT-PCR检测碱性磷酸酶基因表达。结果: 纳米仿生磷灰石涂层比非涂层钛金属表面细胞的增殖数量明显增高，细胞的形态和分布也优于对照组；培养12 d，涂层对细胞ALP基因表达的量明显高于对照组。结论: 钛金属表面纳米仿生磷灰石涂层可以增强细胞的生物效应，提高钛植入体的骨界面早期结合，具有很好的应用前景。     

仿生溶液法诱导钛表面形成钙磷涂层的研究

采用3种不同的方法即不作处理，酸和碱处理但不加热、酸和碱处理后600℃加热对商用纯钛进行表面处理，然后将样品浸泡于仿生溶液中2周后，经过处理的两组样品表面均形成一层薄的钙磷涂层，SEM和EDX分析表明：酸碱处理再经600℃加热组较单纯的酸碱处理组涂层晶体构型均一；XRD分析表明晶体组成主要为含有少量氯元素的羟基磷灰石。     

钛表面微弧氧化涂层的细胞生物活性

背景：微弧氧化技术可改善钛或钛合金的表面特征。 目的：研究纯钛表面微弧氧化涂层的表面性能及其对MC3T3-E1细胞早期黏附、增殖及成骨能力的影响。 方法：将46个直径10 mm、厚度2 mm圆盘状纯钛试件分为实验组和对照组。实验组置于含0.02 mol/Lβ-甘油磷酸二钠盐及0.2 mol/L乙酸钙的电解液中进行微弧氧化处理,对照组对试件进行机械抛光。扫描电子显微镜观察试件表面形貌,X射线能谱分析检测涂层表面钙磷比,X射线衍射分析检测涂层晶相构成。将MC3T3-E1细胞接种在两组试件表面,1,2,4 h电镜下观察细胞形态,在2,4,7 d通过CCK-8方法检测细胞增殖,并于7,14 d检测碱性磷酸酶活性。 结果与结论：经微弧氧化处理后,钛表面形成粗糙多孔的钙磷涂层,微弧氧化涂层主要元素为Ca、P、O及Ti,微弧氧化膜层主要由氧化钛、钛酸钙、磷酸钙及偏磷酸钙构成。电镜观察显示1 h 微弧氧化涂层表面细胞已伸出伪足,4 h呈现较典型的细胞形态。细胞在微弧氧化处理钛表面4,7 d的细胞增殖和7,14 d的碱性磷酸酶活性高于对照组。表明微弧氧化技术生成的粗糙多孔钙磷涂层能显著促进MC3T3-E1细胞的早期黏附、增殖及成骨活性。     

钛基表面纳米银复合涂层的缓释性能

背景:骨科植入材料表面改性可以减少或避免细菌黏附,利用金属表面的特殊涂层释放抑菌及杀菌成分可以预防骨科术后感染。目的:选择不同的制备参数,在医用纯钛表面沉积羟基磷灰石/纳米银复合涂层,观测复合材料表面银离子在模拟体液中的缓释性能。方法:利用脉冲电化学方法,在含银、钙、磷离子的溶液中实现纳米银和羟基磷灰石在钛表面的共沉积,再高温烧结处理制得复合涂层钛材料,用扫描电镜、X射线衍射仪、能谱仪对其形貌、组成进行表征。将分别含有0.5,1 mmol/L银的复合涂层钛材料浸泡在模拟体液中,在不同的时间点用原子能吸收光谱法检测Ag+浓度。结果与结论:复合涂层是由纳米针状羟基磷灰石和点状的银颗粒相互交织成的网状结构,纳米银颗粒在涂层中均匀分布。高温处理后涂层变得致密,羟基磷灰石的晶化度提高,银颗粒在烧结后无团聚现象。在模拟体液中,第1-7天Ag+释放量最大,第7-30天Ag+释放量趋于稳定并维持有效抗菌浓度。含0.5 mmol/L银复合涂层钛材料在30 d时Ag+释放总量低于细胞毒性浓度,含1.0 mmol/L银复合涂层钛材料在30 d时Ag+释放总量接近细胞毒性浓度的临界值,因此含0.5 mmol/L银电解液制备的材料用于临床更安全可靠。     

阳极氧化伴水热处理制备纯钛羟基磷灰石薄涂层

为了解纯钛阳极氧化伴水热处理的技术路线及羟基磷灰石薄涂层在体内的成骨效应，以钛片为阳极，β－磷酸甘油钠和醋酸钙为电解质，经200－400V直流电解15min，维持电流密度≤50mA/cm^2，而后经280℃－300℃水热处理2h，取光滑，喷砂表面作对照，分别植入12只兔股骨内，枯术后4，8，16周取出带种植体骨块制作磨片，观察新骨生成情况及术后8周光滑和涂层种植体的界面超微结构，并作表面能谱分析，结果发现水热处理后，钛片表面出现了羟基磷灰石涂层，动物实验显示涂层种植体8周后编织骨的转化和成熟较快，未见剥脱的羟基磷灰石碎片，其表面的钙，磷含量在种植后增加明显，这说明阳极氧化伴水热处理可以制备出纯钛表面羟基磷灰石薄涂层，其早期促编织骨形成作用明显，可以加快编织骨转化成板层骨。     

仿生法制备纯镁/羟基磷灰石复合涂层的研究

通过酸碱两步法活化纯镁基体表面，用CaCl2和K2HPO4溶液对其进行预钙化处理，将处理过的纯镁试样浸泡于模拟体液中，仿生沉积得到羟基磷灰石涂层。利用X射线衍射和扫描电子显微镜对形成的涂层进行表征。试验结果表明，4周后可在镁基体表面得到了均匀致密、结晶良好的羽毛状羟基磷灰石涂层。     

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。     

多孔碳酸化羟基磷灰石水泥植入修复兔包容性骨缺损的力学分析

背景:采用发泡剂成孔技术,制成了有知识产权的新型骨修复材料多孔碳酸化羟基磷灰石,既保留了碳酸化羟基磷灰石骨水泥原位固化性能等所有的优点,同时又形成多孔结构。目的:通过动物实验观察新型的骨修复材料多孔碳酸化羟基磷灰石水泥修复骨缺损的力学效果。方法:30只新西兰大白兔,手术组25只在双侧股骨髁制备直径为5.5mm、深12mm的骨缺损动物模型,左侧植入多孔碳酸化羟基磷灰石骨水泥为实验组,右侧植入碳酸化羟基磷灰石骨水泥为对照组。非手术组5只,用于正常力学对照。将多孔碳酸化羟基磷灰石骨水泥和碳酸化羟基磷灰石骨水泥试件经模仿体液浸泡,检测力学强度。同时在手术组背肌内分别植入多孔碳酸化羟基磷灰石骨水泥和碳酸化羟基磷灰石骨水泥标准试件。分别于术后2,4,8,12,16周分批处死动物,进行试件骨内和肌内植入的力学实验分析和试件在模仿体液中浸泡后的抗压强度测试。结果与结论:多孔碳酸化羟基磷灰石骨水泥:2周时的骨内力学强度较低,4周时降到最低,8周时接近正常松质骨强度,12周时超过正常松质骨强度,16周时恢复到正常松质骨水平。碳酸化羟基磷灰石骨水泥:2周时骨内植入强度较多孔碳酸化羟基磷灰石骨水泥略高,4周时有所降低,8,12,16周时略升高,但是始终低于正常松质骨的强度。多孔碳酸化羟基磷灰石骨水泥和碳酸化羟基磷灰石骨水泥在SBF中浸泡的抗压强度变化不大。试件植入肌内后抗压强度变化非常显著。结果表明,多孔碳酸化羟基磷灰石水泥具有原位固化性能和一定的力学支撑作用,能作为自体骨移植的一种替代物修复骨缺损。     

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.     

Thin sol-gel-derived silica coatings on dental pure titanium casting

The sol-gel dipping process, in which liquid silicon alkoxide is transformed into a solid silicon-oxygen network, can produce a thin film coating of silica (SiO(2)). The features of this method are high homogeneity and purity of the thin SiO(2) film and a low sinter temperature, which are important in the preparation of coating films that can protect metallic ion release from the metal substrate and prevent attachment of dental plaque. We evaluated the surface properties of dental pure titanium casting coated with a thin SiO(2) or SiO(2)/F-hybrid film by the sol-gel dipping process. The metal specimens were pretreated by dipping in isopropylalcohol solution containing 10 wt% 3-aminopropyl trimethoxysilane and treated by dipping in the silica precursor solution for 5 min, withdrawal at a speed of 2 mm/min, air-drying for 20 min at room temperature, heating at 120 degrees C for 20 min, and then storing at room temperature. Both SiO(2) and SiO(2)/F films bonded strongly (above 55 MPa) to pure titanium substrate by a tensile test. SiO(2(-)) and SiO(2)/F-coated specimens immersed in 1 wt% of lactic acid solution for two weeks showed significantly less release of titanium ions (30. 5 ppb/cm(2) and 9.5 ppb/cm(2), respectively) from the substrate than noncoated specimens (235.2 ppb/cm(2)). Hydrophobilization of SiO(2(-)) and SiO(2)/F-coated surfaces resulted in significant increases of contact angle of water (81.6 degrees and 105.7 degrees, respectively) compared with noncoated metal specimens (62.1 degrees ). The formation of both thin SiO(2) and SiO(2)/F-hybrid films by the sol-gel dipping process on the surface of dental pure titanium casting may be useful clinically in enhancing the bond strength of dental resin cements to titanium, preventing titanium ions release from the substrate, and reducing the accumulation of dental plaque attaching to intraoral dental restorations.     

A physical vapor deposition method for controlled evaluation of biological response to biomaterial chemistry and topography

The purpose of this study was to characterize a technique to effectively mask surface chemistry without modifying surface topography. A thin layer of titanium was deposited by physical vapor deposition (PVD) onto different biomaterial surfaces. Commercially pure titanium disks were equally divided into three groups. Disks were either polished to a mirror finish, grit blasted with alumina particles, or grit blasted and subsequently plasma sprayed with a commercial grade of hydroxyapatite (HA). A subgroup of each of these treatment types was further treated by masking the entire disk surface with a thin layer of commercially pure titanium deposited by PVD. A comparison of surface topography and chemical composition was carried out between disks within each treatment group. Canine marrow cells were seeded on all disk surfaces to determine the stability of the PVD Ti mask under culture conditions. The PVD process did not significantly alter the surface topography of any samples. The thin titanium layer completely masked the underlying chemistry of the plasma sprayed HA surface and the chemistry of the plasma vapor deposited titanium layer did not differ from that of the commercially pure titanium disks. Aliquots obtained from the media during culture did not indicate any significant differences in Ti concentration amongst the Ti and Ti-masked surfaces. The PVD application of a Ti layer on HA coatings formed a stable, durable, and homogenous layer that effectively masked the underlying surface chemistry without altering the surface topography.     

Bone response to calcium phosphate-coated and bisphosphonate-immobilized titanium implants

Thin calcium phosphate (Ca-P) coatings have been introduced to overcome the shortcomings of plasma-sprayed Ca-P coatings. In our previous experiments, thin Ca-P coatings also enabled the immobilization of bisphosphonate, which is a drug used to treat osteoporosis. The present study was designed to evaluate the bone response to titanium implants treated with a thin Ca-P coating and bisphosphonate. Forty cylindrical commercially pure titanium implants with a length of 7 mm and a diameter of 3 mm were used as test implant fixtures. Three groups of surface-treated implants were prepared: (1) blasted with titanium powder and etched with a solution of 10% HF + 5% HNO3 (control); (2) modified with 0.5-microm thick Ca-P coatings and rapid heat-treating, and (3) immobilized with bisphosphonate by immersion in pamidronate disodium solution (10(-2) M) for 24 h at 37 degrees C. These surface-treated implants were inserted into edentulous areas in the mandibular molar region of five beagle dogs. After implantation periods of 4 and 12 weeks, the bone implant interface was evaluated histologically and histomorphometrically. All measurements were statistically evaluated using a one-way ANOVA and Fisher PLSD test for multiple comparisons among the means. Four weeks after the implantation, higher percentage of bone contact was found around the thin Ca-P-coated implants compared to that of the control group. The highest percentage of bone contact was found around the bisphosphonate-immobilized implants after 12 weeks of implantation. These data suggest that a thin coating of calcium phosphate followed by bisphosphonate-immobilization is effective in the promotion of osteogenesis on surfaces of dental implants.     

Biomolecular surface coating to enhance orthopaedic tissue healing and integration

Implant osseointegration is a prerequisite for clinical success in orthopaedic and dental applications, many of which are restricted by loosening. Biomaterial surface modification approaches, including calcium-phosphate ceramic coatings and macro/microporosity, have had limited success in promoting integration. To improve osseointegration, titanium surfaces were coated with the glycine-phenylalanine-hydroxyproline-glycine-glutamate-arginine (GFOGER) collagen-mimetic peptide, selectively promoting alpha2beta1 integrin binding, a crucial event for osteoblastic differentiation. Titanium surfaces presenting GFOGER triggered osteoblastic differentiation and mineral deposition in bone marrow stromal cells, leading to enhanced osteoblastic function compared to unmodified titanium. Furthermore, this integrin-targeted coating significantly improved in vivo peri-implant bone regeneration and osseointegration, as characterized by bone-implant contact and mechanical fixation, compared to untreated titanium in a rat cortical bone-implant model. GFOGER-modified implants also significantly enhanced osseointegration compared to surfaces modified with full-length type I collagen, highlighting the importance of presenting specific biofunctional domains within the native ligand. In addition, this biomimetic implant coating is generated using a simple, single-step procedure that readily translates to a clinical environment with minimal processing and cytotoxicity concerns. Therefore, this study establishes a biologically active and clinically relevant implant-coating strategy that enhances bone repair and orthopaedic implant integration.     

Enhancement of the capability of hydroxyapatite formation on Zr with anodic ZrO₂ nanotubular arrays via an effective dipping pretreatment

Hydroxyapatite (HA) depositions on metallic biomedical implants are widely applied to generate bioactive surfaces in simulated biological environments. Highly ordered anodic ZrO? nanotubes have attracted increasing interest for biomedical applications. However, previous reports showed that at least 14-28 days were required to obtain HA coating on ZrO? nanotubular arrays under biomimetic condition, thus capability to grow HA coating on ZrO ?nanotubular at room temperature needs to be enhanced. In the present work, we demonstrate that ZrO? nanotubular arrays are suitable for an effective dipping treatment to induce more rapid HA coating. A series of ZrO? nanotubular arrays having different dimensions were fabricated in fluoride containing electrolyte. Then, we used a dipping treatment for biomimetic formation of an adhesive HA coating on the nanotubular arrays. The coatings formed rapidly using this procedure under biomimetic conditions and did not require a high-temperature annealing process. The as-formed ZrO? nanotubular arrays were treated using several dip-and-dry steps, through which the nanotubular arrays were filled and covered with calcium phosphate (CaP) nucleation sites. The specimens readily grew HA once immersed in the simulated biological fluid after 2 days immersion. The carbonated HA coating had several micron thickness after 8 days of immersion while only a thin layer of CaP were observed on annealed ZrO? nanotubes immersed in the same solution for the same duration. Tensile testing showed that bonding strength between HA coating and substrate was 21.6 ± 1.6 MPa. This treatment dramatically improves efficiency for promoting HA formation on anodic ZrO? nanotubes at room temperature.     

Bioactive films on metallic surfaces for osteoconduction

A fast and effective electrochemical method was developed to make a dense calcium phosphate films on titanium and stainless steel for hard tissue replacement. The surfaces of titanium and stainless steel were cathodically treated in an electrochemical cell. By controlling the treatment parameters, a film of 100-nm thickness was deposited on the metal surface in several minutes. The thin film was amorphous calcium phosphate containing octacalcium phosphate nuclei, and also dense and ductile. The treated metals were able to induce bioactive calcium phosphate deposition after immersion in simulated body fluid (SBF) for only 1 and 2 days. In vivo study was conducted by implanting the treated specimens of titanium and stainless steel in dog's femur cavity. The treated metallic surfaces showed good ability of osteoconduction. This surface treatment method can be potentially used to enhance bioactivity of any type of metallic surfaces.     

Characterization and protein-adsorption behavior of deposited organic thin film onto titanium by plasma polymerization with hexamethyldisiloxane

Plasma polymerized hexamethyldisiloxane (HMDSO) thin film was deposited onto titanium using a radio-frequency apparatus for the surface modification of titanium. A titanium disk was first polished using colloidal silica at pH=9.8. Plasma-polymerized HMDSO films were firmly attached to the titanium by heating the titanium to a temperature of approximately 250 degrees C. The thickness of the deposited film was 0.07-0.35mum after 10-60min of plasma polymerization. The contact angle with respect to double distilled water significantly increased after HMDSO coating. X-ray photoelectron spectroscopy revealed that the deposited thin film consisted of Si, C, and O atoms. No Ti peaks were observed on the deposited surface. The deposited HMDSO film was stable during 2-weeks immersion in phosphate buffer saline solution. Fourier transform reflection-absorption spectroscopy showed the formation of Si-H, Si-C, C-H, and Cz.dbnd6;O bonds in addition to Si-O-Si bonds. Quartz crystal microbalance-dissipation measurement demonstrated that the deposition of HMDSO thin films on titanium has a benefit for fibronectin adsorption at the early stage. In conclusion, plasma polymerization is a promising technique for the surface modification of titanium. HMDSO-coated titanium has potential application as a dental implant material.     

The role of calcium gluconate in electrochemical activation of titanium for biomimetic coating of calcium phosphate

Supersaturation of calcium and phosphate in the bath solution and activation of the metal substrate is essential for effective biomimetic growth of apatite on orthopedic implants. In this work, bioactivation of titanium surface was achieved by electrodeposition of a thin layer of calcium phosphate followed by an alkaline treatment to obtain pure hydroxyapatite crystals. The influence of calcium gluconate in the electrolyte solution was evaluated and optimized. Adhesive strength, thickness, structural, and surface characteristics were evaluated. A highly adhesive and uniform layer of hydroxyapatite was formed on titanium surface when the electrodeposition was carried out with an electrolyte solution-containing calcium gluconate. The electrodeposited hydroxyapatite coatings were subjected for biomimetic growth in Kokubo's simulated body fluid (SBF) and Kokubo's modified SBF containing 1.5 times higher concentration of Ca. Biomimetic growth was also improved by the addition of calcium gluconate in the SBF solution.