低温等离子体对血管内金属支架的表面改性

生物材料用于人体必须要具备生物相容性。尤其是与血液相接触的材料如血管内支架必须要具备血液相容性。材料的表面特性直接影响血液系统中是否会出现血栓。本针对金属血管内支架的表面特性、与血液的界面反应以及用于提高血液相容性的低温等离子表面改性进行了简要综述。     

NiTi基C型聚对二甲苯膜等离子体处理的表面能及生物相容性

本文对ＮｉＴｉ基Ｃ型聚对二甲苯膜表面经等离子体处理后进行表面浸润角和表 力的测定,从材料表面能的角度探讨其与材料表面血液相容性的关系和特性网状血管内支架动物实验结果。     

管腔内支架用金属材料的生物相容性及其表面改性

管腔内金属支架是用于植入人体各管道狭窄处起支撑作用的医疗器械,因其与人体组织直接接触,故对支架的生物相容性的研究十分重要。本文对用于管腔内支架的３１６Ｌ不锈钢和ＮｉＴｉ合金的耐腐蚀性和生物相容性进行了综合评述;并以冠状动脉支架为应用背景,着重分析了影响血管内支架血液相容性的因素,提出了对支架进行表面改性处理以提高其血液相容性的技术路线。     

生物高分子材料血液相容性研究

生物高分子材料广泛应用于临床医疗,可用作人工血管、起搏器、组织工程支架等,因而必须具备良好的血液相容性.综述了生物高分子材料血液相容性的研究现状,主要包括凝血、血栓形成机理以及抗凝血系统等,重点介绍了高分子材料植入体内引起凝血及血栓形成的具体机制,阐述了设计微相分离结构、化合物接枝改性、引入生物活性分子、材料表面内皮化等改善材料血液相容性的主要途径.最后从分子生物学角度出发展望了今后高分子材料改性的研究方向.     

医用Mg-RE合金血管内支架的研究进展

血管内金属支架是植入人体血管管道狭窄处起支撑作用的医疗器械,其生物相容性十分重要.分析了稀土镁合金作为生物材料的优势和潜力,对Mg-RE合金的腐蚀性、生物相容性及生物可降解性能进行了综合评述;并以冠状动脉支架为应用背景,着重分析了影响血管内支架血液相容性的因素,提出了对支架进行表面改性处理以提高其血液相容性的技术路线.     

生物医用高分子材料的生物相容性及其表面改性技术

生物医用高分子材料是一类具有广泛用途的高科技产品,具有十分重要的应用价值和发展前景。生物相容性是生物医用高分子材料必须具备的优良特性,是材料产品成功应用的关键。目前,人们主要通过材料表面改性来提高生物医用高分子材料的生物相容性,以保证材料与机体相适应,生物医用高分子材料表面改性技术也因此成为人们竞相研究开发的热点。简述了生物医用高分子材料的生物相容性及其表面改性技术的相关问题。     

新型含铜金属心血管支架材料

针对心血管支架内再狭窄问题(ISR),作者团队利用Cu元素对心血管系统的有益生物功能,创新地发展出具有生物功能的新型含铜血管支架材料(含铜不锈钢及钻基合金)。综述了近年来团队在新型含铜金属血管支架材料方面的研究进展。研究结果表明,含铜金属血管支架材料能促进内皮细胞增殖及迁移,并降低其凋亡率;对动脉平滑肌细胞增殖及迁移具有抑制作用,并促进其凋亡;减少血小板在支架表面的粘附,延长动态凝血时间,降低血栓形成倾向。此外,新型含铜金属血管支架材料还具有有优异的生物相容性。动物实验结果表明,含铜不锈钢心血管支架在动物体内可明显促进内皮化、抑制血栓形成,且生物相容性好,可以抑制支架内再狭窄的发生,有望得到临床应用。     

可降解血管支架材料降解行为研究进展

目前可降解血管支架材料包括聚合物、镁合金、铁合金及锌合金,它们的降解特性直接影响其作为血管支架植入后的支撑能力、局部反应和血管修复的预后。聚合物降解时间较易调整、生物相容性较好,但力学性能不足;镁合金的降解存在降解速率快、释氢反应和微环境pH值变化较大的问题;铁合金降解速率太慢;锌合金的降解速率适中,是近年可降解血管内植入材料研究热点。除了材料自身的特性,可降解材料的血管内降解行为还受到环境的离子浓度、酶、pH值和温度等多种因素的影响。综述了目前不同血管内可降解支架材料在模拟体液及动物体内生物降解行为的研究结果,以期为血管内可降解材料研究和产品开发提供参考。     

静电纺PLA/姜黄素复合薄膜血液相容性研究

为了研究静电纺PLA/姜黄素复合薄膜血液相容性,将PLA和姜黄素溶解在三氯甲烷和丙酮体积比为2:1的混合溶剂中,采用静电纺丝技术分别制备纯PLA和姜黄素质量分数为3％的PLA/姜黄素复合薄膜,通过血小板聚集、动态凝血和溶血实验,评价静电纺PLA/姜黄素复合薄膜的血液相容性.实验表明:静电纺复合薄膜的血小板聚集抑制率为53.47％,远大于静电纺纯PLA薄膜的9.43％;复合薄膜的BCI始终大于纯PLA薄膜,且随着时间的延长BCI曲线下降缓慢;PLA/姜黄素复合薄膜的溶血率＜5％,对红细胞的破坏程度很小.故静电纺PLA/姜黄素复合薄膜具备良好的血液相容性,为制备血管支架材料或对现有血管支架材料加膜等方面有潜在的应用价值.     

胆道支架材料生物相容性的研究

胆道支架不仅要求具备优异的力学性能,更重要的是材料在胆道环境中具有良好的生物相容性.采用非平衡磁控溅射设备在不锈钢基体上制备了Ti-O薄膜,研究了其结构及与病人胆汁相互作用.结果表明,Ti-O膜表面具有较高的表面能,不利于细菌粘附及生物膜形成,胆汁稳定性和胆红素变化也是影响支架材料相容性的主要原因,这对开发新型胆道支架...     

Improvement of haemocompatibility of metallic stents by polymer coating

An alternative to open heart surgery in treating arterial diseases causing restricted blood flow is the implantation of intracoronary metallic stents. In spite of the advances in implantation and in spite of the excellent mechanical properties of metallic stents, there are still limitations because of the thrombogenicity of the metal. We have, hence, directed our attention to the coating of metallic stents with an ultrathin polymer layer by chemical vapor deposition (CVD) polymerization of 2-chloroparacyclophan. In a second step of surface modification the poly(2-chloroparaxylylene) layer is modified by treatment with a sulfur dioxide plasma in order to obtain a more hydrophilic surface with new functional groups. The results demonstrate the stable polymer coating of the stents and the improvement of haemocompatibility after treatment with sulfur dioxide plasma. Platelet adhesion is decreased from 85% for the metal surface to 20% for the CVD-coated and sulfur-dioxide-plasma treated surface. © 1999 Kluwer Academic Publishers     

Surface modification of Ti–6Al–4V alloy for biomineralization and specific biological response: Part I,inorganic modification

Titanium and its alloys represent the gold standard for orthopaedic and dental prosthetic devices, because of their good mechanical properties and biocompatibility. Recent research has been focused on surface treatments designed to promote their rapid osteointegration also in case of poor bone quality. A new surface treatment has been investigated in this research work, in order to improve tissue integration of titanium based implants. The surface treatment is able to induce a bioactive behaviour, without the introduction of a coating, and preserving mechanical properties of Ti6Al4V substrates (fatigue resistance). The application of the proposed technique results in a complex surface topography, characterized by the combination of a micro-roughness and a nanotexture, which can be coupled with the conventional macro-roughness induced by blasting. Modified metallic surfaces are rich in hydroxyls groups: this feature is extremely important for inorganic bioactivity (in vitro and in vivo apatite precipitation) and also for further functionalization procedures (grafting of biomolecules). Modified Ti6Al4V induced hydroxyapatite precipitation after 15 days soaking in simulated body fluid (SBF). The process was optimised in order to not induce cracks or damages on the surface. The surface oxide layer presents high scratch resistance.     

Molecular Hemocompatibility of Graphene Oxide and Its Implication for Antithrombotic Applications

Surface‐induced blood clotting is one of the major problems associated with the long‐term use of blood‐contacting biomedical devices. Central to this obstructive blood clotting is the adsorption of plasma proteins following the interactions between blood and material surface. Of all proteins circulating in the blood plasma, albumin and fibrinogen are the two important proteins regulating the blood–material interaction. As such, the adsorption of plasma proteins has been used as an indicator for the assessment of the blood compatibility of the biomedical devices. Numerous nanomaterials have been developed for antithrombotic surface coating applications, including the 2D graphene and its derivatives. Here, the antithrombotic property of albumin‐functionalized graphene oxide (albumin‐GO) and its potential for antithrombotic coating application under flow are investigated. The loading capacities, conformational changes, and adsorptions of albumin and fibrinogen on GO are probed. It is observed that GO possesses a high loading capacity for both proteins and simultaneously, it does not disrupt the overall secondary structure and conformational stability of albumin. Both albumin and fibrinogen adsorb well on the surface of GO. Subsequently, it is demonstrated that the albumin‐functionalized GO possesses enhanced antithrombotic effect and may potentially be used as an antithrombotic coating material of blood‐contacting devices under dynamic flow.     

High-performance organic optoelectronic devices enhanced by surface plasmon resonance

The surface plasmon effect on polymer solar cells and polymer light-emitting diodes is demonstrated by using metal nanoparticles prepared from block copolymer templates. Light absorption of the polymer thin layer is increased with the incorporation of metallic nanostructures, resulting in a significant surface plasmon effect in the optoelectronic devices.     

Electron transfer behavior of monolayer protected nanoclusters and nanowires of silver and gold

Understanding the electron transfer behavior of nanometer sized, both metallic and semiconducting particles and wires is important due to the fundamental interest in size and shape dependent electronic properties and also because of its applications in nano-electronic devices like single electron transistors and molecular switches. Monolayer protected nanoclusters enable one simple and elegant method of synthesis of these types of metallic and semiconducting materials using interfacial chemistry as has been successfully used in several applications ranging from catalysis to molecular electronics. The success of this type of nanostructured materials is due in part to the well known protecting/stabilizing action of the ligands (also known as surface passivating/capping agents), which facilitate the synthesis and processing of these hydrophobic colloids in solution form. The present article discusses the electron transfer behavior of silver nanowires and nanoparticles with varied sizes. In particular, we have investigated the electrochemical properties of silver nanowires (diameter 70 nm, length several micrometers) and compared with the behavior of similar relatively larger sized nanoparticles (size 40 nm). A critical analysis of the redox behavior of silver nanowires and nanoparticles is presented in aqueous medium under various electrolytic conditions along with a comparison of analogous properties of smaller sized (2-7 nm) silver and gold nanoclusters.     

表面改性在生物医用材料研究中的应用

在植入物体性能较好的基础上,表面性能是决定其生物相容性是否良好的至关重要因素。本文针对硬组织和与血液相接触的金属植入物,对表面改性技术、表面改性膜层特点及其应用进行了综合评述,探讨了通过表面改性提高植入物生物相容性的机理,并指出了生物医用材料表面改性的研究发展方向。     

Deposition of boron doped DLC films on TiNb and characterization of their mechanical properties and blood compatibility

Abstract

Diamond-like carbon (DLC) material is used in blood contacting devices as the surface coating material because of the antithrombogenicity behavior which helps to inhibit platelet adhesion and activation. In this study, DLC films were doped with boron during pulsed plasma chemical vapor deposition (CVD) to improve the blood compatibility. The ratio of boron to carbon (B/C) was varied from 0 to 0.4 in the film by adjusting the flow rate of trimethylboron and acetylene. Tribological tests indicated that boron doping with a low B/C ratio of 0.03 is beneficial for reducing friction (μ = 0.1), lowering hardness and slightly increasing wear rate compared to undoped DLC films. The B/C ratio in the film of 0.03 and 0.4 exhibited highly hydrophilic surface owing to their high wettability and high surface energy. An in vitro platelet adhesion experiment was conducted to compare the blood compatibility of TiNb substrates before and after coating with undoped and boron doped DLC. Films with highly hydrophilic surface enhanced the blood compatibility of TiNb, and the best results were obtained for DLC with the B/C ratio of 0.03. Boron doped DLC films are promising surface coatings for blood contacting devices.     

Metallic nanowire-graphene hybrid nanostructures for highly flexible field emission devices

We report a simple but efficient method to prepare metallic nanowire-graphene (MN-G) hybrid nanostructures at a low temperature and show its application to the fabrication of flexible field emission devices. In this method, a graphene layer was transferred onto an anodic alumina oxide template, and vertically aligned Au nanowires were grown on the graphene surface via electrodeposition method. As a proof of concept, we demonstrated the fabrication of flexible field emission devices, where the MN-G hybrid nanostructures and another graphene layer on PDMS substrates were utilized as a cathode and an anode for highly flexible devices, respectively. Our field emission device exhibited stable and high field emission currents even when bent down to the radius of curvature of 25 mm. This MN-G hybrid nanostructure should prove tremendous flexibility for various applications such as bio-chemical sensors, field emission devices, pressure sensors and battery electrodes.     

Electron pumping in graphene mechanical resonators

The combination of high-frequency vibrations and metallic transport in graphene makes it a unique material for nanoelectromechanical devices. In this Letter, we show that graphene-based nanoelectromechanical devices are extremely well suited for charge pumping due to the sensitivity of its transport coefficients to perturbations in electrostatic potential and mechanical deformations, with the potential for novel small scale devices with useful applications.