真空磁过滤电弧离子镀沉积Ti-O薄膜及其血液相容性

采用真空磁过滤电弧离子镀技术在单晶硅(100)和载玻片表面沉积Ti-O薄膜,研究了不同氧分压(0.08、0.13、0.2Pa)对薄膜结构及血液相容性的影响.研究结果表明,随着氧分压的提高,Ti-O薄膜相结构从三氧化二钛转变为金红石结构二氧化钛.扫描电子显微镜观察表明,所制备薄膜表面结构致密,与基体结合紧密.血小板粘附实验结果表明,0.13Pa下制备的薄膜血液相容性优异,优于临床应用的热解碳材料.     

Ti-O薄膜的溅射刻蚀微形貌表面对内皮细胞生长的影响

利用磁控溅射合成具有一定特性的Ti-O薄膜,并采用Ar离子溅射刻蚀该薄膜表面.运用原子力显微镜(AFM),X射线衍射(XRD)对刻蚀后的薄膜表面微观形貌、微结构进行表征.结果表明薄膜的结构未发生变化,表面的粗糙度减小.进一步的人脐静脉内皮细胞(HUVEC)种植实验表明表面粗糙度的变化对内皮细胞的贴附、生长与增殖有很大的影响.     

血管支架表面沉积Ti-O薄膜的力学性能

采用非平衡磁控溅射法在血管支架上制备Ti-O薄膜、重点研究了支架表面薄膜厚度、内外表面薄膜差异及两种变形方式下薄膜的力学性能.支架表面积用精密MES电子天平称得质量计算得到,薄膜厚度通过薄膜质量与支架表面积的关系求得;用X-射线电子能谱(EDX)分析了支架内外表面薄膜成份及含量;对支架压缩、撑开并选取变形量大、应力集中单元筋进行研究,用扫描电子显微镜(SEM)观察薄膜是否有破坏.结果表明,在该工艺下支架表面薄膜平均厚度为9.98nm,支架内外表面薄颜色泽均匀,薄膜附着性良好,在支架压缩和撑开过程中,应力大的单元筋表面没有观察到薄膜的开裂、剥落,薄膜的力学性能可靠.     

二氧化钛薄膜亲水性恢复研究

新制备的锐钛矿TiO2薄膜具有超亲水性,在使用和储存过程中超亲水性会降低.本文探究恢复亲水性的方法,采用热处理、等离子体辐照、紫外光照射等技术恢复锐钛矿TiO2薄膜亲水性,三种方法均能够有效地恢复薄膜表面的亲水性.热处理及紫外光照射操作简单而经过等离子体辐照的薄膜能保持更长时间的可见光致亲水性.     

微图形氧化钛薄膜表面内皮细胞生长行为研究

采用非平衡磁控溅射沉积技术制备微图形化的Ti-O薄膜,通过在微图形化的薄膜表面培养内皮细胞的方法,研究了微图形及表面物理化学性能对细胞生长行为的影响.结果表明,微图形尺寸减小到某一尺度范围之内会对内皮细胞在材料表面的生长起到接触引导作用,促进细胞在其表面生长;同时,表面成分、结构和表面能参数γsp/γsd也在一定程度上影响内皮细胞的生长行为.采用溅射技术使材料表面具有一定特征的表面微观形貌,能够引导和促进细胞在材料表面的生长,溅射技术制备微图形化表面可能成为等离子体生物材料表面改性的一个新的技术手段.     

Si-N-O薄膜结构对薄膜血液相容性的影响

采用非平衡磁控溅射(UBMS450)法在(100)单晶硅表面制备Si-N-O薄膜.利用X射线光电子能谱(XPS)表征薄膜的成分结构;用血小板粘附试验表征薄膜结构对薄膜血液相容性的影响.研究结果表明,以无机Si为主的Si-N-O薄膜,其血液相容性较差;键合少量O的Si3N4薄膜,其血液相容性较佳.Si-N-O薄膜中N含量和O含量的变化,是导致薄膜结构变化的重要因素.     

AP-CVD法制备的二氧化钛薄膜结构及亲水性研究

基于实现在线镀膜的目的,研究了以TiCl4为钛源,用AP-CVD法在玻璃基板上制备TiO2薄膜的工艺.利用扫描电子显微(SEM)技术和X射线衍射(XRD)技术,研究了不同基板反应温度下薄膜的表面形貌和晶体结构,分析了表面形貌和结构对亲水性的影响.结果表明通过改变反应温度可以控制锐钛矿和金红石的相对量,薄膜的亲水性和表面形貌、粗糙度有密切的关系.     

热处理对TiO2薄膜制备及亲水性的影响

采用廉价的TiCl_4为前驱体水解合成TiO_2水溶胶,利用辊涂装置镀膜并通过热处理制得了一系列TiO_2薄膜。运用X射线粉末衍射(XRD)、扫描电镜(SEM)、紫外-可见光谱(UV-Vis)、光致发光谱(PL)对TiO_2薄膜进行了表征,并采用接触角测量仪考察了热处理温度、避光保存时间、UV光照时间对各薄膜亲水性的影响。结果表明,制得的薄膜不影响玻璃基材的可见光透过率;通过热处理,能有效增强薄膜对可见光的吸收能力,显著抑制光生电子和空穴的复合;当热处理温度为450℃时,TiO_2薄膜表现出了最好的亲水性,其薄膜与水的接触角达到0°。     

改性纳米TiO_2薄膜超亲水性的研究进展

纳米TiO2超亲水薄膜是新型的功能性薄膜,在自洁、防雾和生物兼容性应用等方面起着重要的作用。由于普通的TiO2薄膜禁带宽度较大,亲水性能不佳,使其实际应用受到极大的限制,改性是提高TiO2薄膜超亲水性能的重要手段。因此,对TiO2进行改性就成为该领域的关键课题之一。文中综述了纳米TiO2薄膜的超亲水性机理,以及实现超亲水性表面的改性方法。     

热处理温度对TiO2薄膜光催化及亲水性的影响

采用溶胶-凝胶法及浸渍提拉法在普通的载玻片上制得TiO2薄膜,通过对薄膜及相应粉体的XRD、IR谱及薄膜致密度的测量,分析了热处理温度对TiO2薄膜光催化及超亲水特性的影响.结果表明:薄膜经过不同温度的热处理,光催化活性不同,亲水性能也有显著的差别,经450℃热处理的薄膜光催化活性最高,而在450～550℃的热处理温度范围得到了接触角为0°的超亲水性薄膜;薄膜表面的超亲水性与薄膜中TiO2的晶型、羟基浓度及薄膜的孔隙度有关.     

Monocyte adhesion and adhesion molecule expression on human endothelial cells on plasma-treated PET and PTFE in vitro

The aim of this study was to evaluate in vitro the inflammatory potential of endothelialized surfaces of polyethylene terephthalate (PET) and polytetrafluorethylene (PTFE) after ammonia gas plasma modification. HUVECs grown on polystyrene and HUVECs stimulated with tumor necrosis factor (TNF-alpha) were used as controls. At day 1 and day 7, surfaces were evaluated for U937 cells and HUVECs using flow cytometry and immunohistochemistry. Plasma-treated PET (T-PET) and treated PTFE (T-PTFE) increased U937 cell adhesion compared to the negative control but this was not statistically significant. Maximal adhesion of U937 cells to HUVEC was observed on TNF-alpha stimulated endothelium with significant differences between day 1 and day 7. There was a small increase in U937 cell adhesion to plasma-treated PET compared to PTFE on both day 1 and day 7, but this was not statistically significant. Immunohistochemical staining demonstrated two patterns of distribution for monocyte adhesion on materials. On T-PET the cells were positioned in clusters attached to HUVECs and on T-PTFE the cells were randomly distributed on HUVECs and material. The effects of plasma-treated PET and PTFE on HUVEC adhesion and proliferation were also studied. On day 1 there were slight increases in the growth of HUVECs on both of T-PET and T-PTFE but this was not statistically significant. On day 7, cell number increased significantly on all of surfaces compared to the negative control. The results demonstrate that the plasma treatment of PET and PTFE with ammonia improves the adhesion and growth of endothelial cells and these surfaces do not exhibit a direct inflammatory effect in terms of monocyte adhesion. Plasma-treated PTFE enhances HUVECs growth and was less adhesive for monocytes as compared with treated PET. The monocyte adhesion to endothelial cells on surfaces can be used as a tool for the evaluation of material surface modification and further to study the mechanisms of cell to cell interactions in response to surfaces.     

Optimization of thin film wetting and adhesion behavior

The coatability and adhesion behavior of photoresist films on semiconductor device substrates is related to the magnitudes of the polar components of surface energy of the two materials. The best adhesion during wet etching is achieved if the polar surface energy component γ^p of both the film and the substrate is small. However, in the case of a resist with a reasonably large γ^p, it is necessary to make the γ^p of the substrate sufficiently large to permit good wetting. It is thought that these results are applicable to other thin film-substrate combinations and to adhesion failure during exposure to many different reactive ambients.     

Remodeling of fibrinogen by endothelial cells in dependence on fibronectin matrix assembly. Effect of substratum wettability

The endothelization of cardiovascular implants is desirable to improve their blood compatibility. The capacity of the endothelial cells to attach, migrate, proliferate and function on the implant surface depends on the presence of matrix proteins such as fibronectin (FN) and fibrinogen (FNG). In this study, we show that the deposition of fibrinogen into extracellular matrix-like structures by human umbilical vein endothelial cells (HUVEC) is dependent on FN matrix formation. We found further that the process of organization of both adsorbed and soluble FN and FNG is dependent on the wettability of materials since it was observed only on a hydrophilic and not on a hydrophobic model surface. ₃ integrin was involved in the process of cell attachment to adsorbed FNG, while the mechanism of FNG fibrillogenesis required the activity of the ₁ integrin. Studies of EC morphology showed the predominant peripheral organization of actin filaments and the formation of distinct leading and trailing cell edges suggesting a motile phenotype of cells when they are seeded on FNG. In summary, we concluded that adsorbed fibrinogen may enhance the motility of HUVEC and that soluble FNG requires FN matrix assembly to be organized in fibrilar structures.     

等离子体聚合沉积聚烯丙胺薄膜改性医用不锈钢及内皮细胞粘附行为研究

采用等离子体聚合沉积方法,通过调控占空比参数,在医用不锈钢表面合成含有伯胺基的聚烯丙胺薄膜,并进一步在聚烯丙胺薄膜表面固定了明胶分子.漫反射傅立叶红外光谱和X射线光电子能谱的分析结果表明聚烯丙胺薄膜表面含有伯胺基团,明胶分子有效地固定到了聚烯丙胺薄膜表面.静态接触角测试结果表明固定了明胶分子的聚烯丙胺薄膜表现出较好的亲水性,具有较高的表面能.体外内皮细胞粘附实验及Alamar Blue评价结果表明固定了明胶分子的聚烯丙胺薄膜表现出良好的促内皮细胞粘附性能,且固定明胶分子的脉冲等离子体聚烯丙胺薄膜表面表现出更高的内皮细胞活性.     

图形化表面TiO2薄膜的制备及其对内皮细胞附着形态的影响

采用光刻技术和反应离子刻蚀法(RIE)先在硅表面制备出一系列平面尺寸不同的微图形阵列,然后采用溶胶凝胶(sol-gel)浸渍提拉法在其表面制备出均匀致密、表面粗糙度一致的锐钛矿型纳米晶TiO2薄膜.利用扫描电镜(SEM)和免疫荧光标记实验研究图形尺寸对人脐静脉内皮细胞(HUVEC)附着形态的影响.实验结果发现在化学成分、细胞毒性、表面粗糙度都不对细胞附着形态产生影响的条件下,HUVEC对图形尺寸的响应为:当平面空间足够时细胞的附着伸展性能较好,而当没有足够的平面空间时细胞的附着伸展性能较差.     

In vitro assessment of endothelial cell adhesion mechanism on vascular patches

Endothelial cell (EC) seeding of small caliber vascular grafts prior to their implantation has proved to significantly improve long-term patency in humans. We have previously demonstrated that a monolayer of EC could be obtained on type I collagen-coated knitted ultrathin polyster grafts (InterVascular, La Ciotat, France). Thus, the aim of the present work was to understand the nature of cell adhesion mechanisms involved in the cell /biomaterial interface, using HemaCarotid^® (InterVascular) patches made of type I collagen-coated knitted ultrathin polyster (type I collagen is used to coat patches to attain low permeability). By means of quantitative attachment tests, adhesion blocking assays, RT–PCR for the expression of ₁ integrin mRNA, indirect immunofluorescence with antivinculin antibody, we were able to show that EC are able to adhere to such surfaces by the means (non-unique) of cell surface receptors of the ₁ integrin group. However, the latter are probably downregulated at the cell/biomaterial interface.     

Enhanced adhesion of osteoblastic cells on polystyrene films by independent control of surface topography and wettability

We independently controlled surface topography and wettability of polystyrene (PS) films by CF₄ and oxygen plasma treatments, respectively, to evaluate the adhesion and proliferation of human fetal osteoblastic (hFOB) cells on the films. Among the CF₄ plasma-treated PS films with the average surface roughness ranging from 0.9 to 70 nm, the highest adhesion of hFOB cells was observed on a PS film with roughness of ~ 11 nm. When this film was additionally treated by oxygen plasma to provide a hydrophilic surface with a contact angle less than 10°, the proliferation of bone-forming cell was further enhanced. Thus, the plasma-based independent modification of PS film into an optimum nanotexture for human osteoblast cells could be appplied to materials used in bone tissue engineering.     

Tissue-engineered endothelial cell layers on surface-modified Ti for inhibiting in vitro platelet adhesion

Abstract

A tissue-engineered endothelial layer was prepared by culturing endothelial cells on a fibroblast growth factor-2 (FGF-2)–l-ascorbic acid phosphate magnesium salt n-hydrate (AsMg)–apatite (Ap) coated titanium plate. The FGF-2–AsMg–Ap coated Ti plate was prepared by immersing a Ti plate in supersaturated calcium phosphate solutions supplemented with FGF-2 and AsMg. The FGF-2–AsMg–Ap layer on the Ti plate accelerated proliferation of human umbilical vein endothelial cells (HUVECs), and showed slightly higher, but not statistically significant, nitric oxide release from HUVECs than on as-prepared Ti. The endothelial layer maintained proper function of the endothelial cells and markedly inhibited in vitro platelet adhesion. The tissue-engineered endothelial layer formed on the FGF-2–AsMg–Ap layer is promising for ameliorating platelet activation and thrombus formation on cardiovascular implants.     

Effect of hydrophobicity on in vitro streptococcal adhesion to dental alloys

Non-specific interactions such as electrostatic interactions, and surface free energy are of importance in bacterial adhesion to dental surfaces as they determine whether or not bacteria are attracted to the surface. The relationship between adherence of Streptococcus mitis, S. mutans, S. oralis and S. sanguinis on precious and non-precious dental alloys, and the bacterial and alloy surface hydrophobicities (a measure of the surface free energy) was studied. The number of adhering bacteria was determined by fluorescence microscopy counts. The hydrophobicity of the bacteria and alloy surfaces were evaluated by adhesion to hexadecane and water contact angles, respectively. Our results showed that (i) the surfaces of the tested alloys were hydrophobic, (ii) S. sanguinis, S. mutans and S. oralis were hydrophobic, and (iii) S. mitis was hydrophilic. S. oralis, the more hydrophobic strain, demonstrated the highest adherence on the tested materials, whereas S. mitis adhered least on the hydrophobic surfaces. For the tested alloys, bacterial adherence was highest for the high gold content alloy, and lowest for the non-precious alloy. Our results showed that for the tested bacterial strains, there was a significant correlation between bacterial adhesion and substratum hydrophobicity: hydrophobic metal surfaces favor adhesion of hydrophobic bacteria.