疏水疏油纳米银修饰不锈钢材料的制备及生物相容性

采用恒电位电化学沉积法在316L不锈钢表面沉积银纳米修饰层,并置于全氟硅烷溶液中进行疏水修饰,通过控制沉积时间和修饰过程,制备了一系列具有不同界面亲疏水特性的修饰材料.采用扫描电子显微镜(SEM)、能量散射X射线光谱(EDX)仪及接触角测量仪等对材料性能进行了表征;利用四甲基偶氮唑盐(MTT)法和流式细胞仪等检验了材料的血液相容性;并将修饰后的316L不锈钢植入实验动物体内,检验其组织相容性.实验结果表明,该纳米银全氟硅烷修饰的316L不锈钢材料比316L裸不锈钢具有更好的血液及组织相容性,有望成为一种理想的血管支架应用材料.     

聚砜共价键合磷铵两性离子的结构修饰及其血液相容性的研究

利用形成碳-氧键将磷铵两性离子(1)共价键合到聚砜(PSF)材料表面,改善其抗凝血性能.首先对聚砜(PSF)进行氯甲基化反应,生成苄氯结构,然后通过自合成两性离子化合物1中的—OH与氯甲基化聚砜的—CH2Cl反应形成醚键,将两性离子结构接枝在PSF上.用ATR-FTIR、EA和1H-NMR表征了产物结构,并通过水接触角、溶血实验和血小板黏附实验对结构修饰前后材料的亲水性和抗凝血性能进行了比较.改性PSF材料的表面亲水性提高,几种改性PSF材料的溶血率均低于5%,PSF-18.1%1材料的表面几乎没有血小板黏附.结果表明,磷铵两性离子结构修饰的聚砜材料可以显著提高其血液相容性,在血液相容性材料等领域具有潜在的应用价值.     

微纳米多孔不锈钢表面高效吸附活性生物大分子

不锈钢(AISI 316L)是目前在医药器械中应用最为广泛的商业化材料. 下一代的不锈钢智能材料将特殊功能的生物活性分子(或纳米粒子)修饰在金属表面以模拟组织功能、提高生物/细胞相容性, 这是目前材料科学研究的热点领域之一. 本文研究了具有微纳米多孔表面结构的316L 不锈钢对抗体和生物酶分子的吸附作用,并与这些生物分子在光滑表面以及镀金表面的吸附进行了比较. 研究发现不锈钢可通过简单的电化学腐蚀方法在表面产生微纳米多孔结构. 微纳米孔不锈钢表面可稳定地吸附抗体或辣根过氧化物酶分子, 其吸附量与喷镀金表面相当或更好. 用表面活性剂(10%牛血清白蛋白(BSA)或0.2% Tween-20)洗涤不能除去吸附的蛋白.用5% Tween-20 预处理金属表面, 则可减少一半的抗体吸附量; 但表面活性剂预处理对辣根过氧化物酶的吸附没有影响. 吸附蛋白质后的金属表面湿润度大大增加; 蛋白质修饰的微纳米孔不锈钢表面表现出了很好的亲水性(水接触角小于50°), 指示了很好的生物相容性. 而金属表面的湿润度则主要取决于蛋白质物种, 并与蛋白质的吸附量正相关. 吸附于不锈钢微纳米孔表面的抗体仍保持了良好的生物活性; 用此种方式制备的抗CD34抗体修饰的不锈钢血管支架可以高密度并高选择性地吸附其目标细胞(如KG-1细胞). 本文工作为未来制备新型的无高聚物涂层的不锈钢智能医学生物材料提供了基础.     

表面改性SUS316L不锈钢的电化学行为研究

分别以表面镀Rh,表面离子束增强沉积Ta2O5膜及溶胶凝胶法沉积TiO2膜对冠状动脉支架用材料SUS316L不锈钢进行表面改性.采用电化学方法研究了该表面改性试样在Tyrode's模拟人工体液中的电化学行为.结果表明,上述3种表面改性方法均可提高SUS316L不锈钢在模拟人工体液中的阳极极化性能.其中对于采用离子束增强法沉积的Ta2O5膜和溶胶凝胶法沉积的TiO2膜,因Ta和Ti上的d轨道空位已被氧的电子占据,不利于氢吸附,从而抑制了阴极的析氢过程.X射线衍射分析发现,3种改性方法在SUS316L不锈钢表面依次形成均匀而致密的Rh金属层,Ta2O5的无序膜层和TiO2晶态膜层,阻止了合金元素的溶解,改善不锈钢的电化学性能.     

镀银-石墨涂层316L不锈钢双极板的电化学性能测试及表征

316L不锈钢以其质轻,价廉,易加工成型以及良好的导电导热性能而成为极具潜力的质子交换膜燃料电池双极板材料,但其在电池运行环境中仍有一定缺陷.在阴极条件下不锈钢板易钝化,增加了与碳纸扩散层间的界面接触电阻;而在阳极条件下,则由于金属离子的溶解,污染了膜电极,引起催化剂中毒,从而降低电池输出功率,影响电池性能.本文采用喷涂技术在316L不锈钢表面制备导电石墨涂层,测得其与Toray060碳纸的接触电阻为80.6mΩ·cm2.如果在制备石墨涂层前预镀薄层银,则可使其接触电阻降至19.8mΩ·cm2.因此,本文利用Tafel曲线、恒电位氧化等电化学方法,对该镀银-石墨涂层316L不锈钢与原316L不锈钢和镀银316L不锈钢在模拟质子交换膜燃料电池阴、阳极工作环境条件下的耐腐蚀性能进行了研究.结果表明,镀银不锈钢和镀银-石墨涂层不锈钢较原不锈钢的腐蚀电位分别提高了0.49和0.35V,腐蚀电流密度下降1-2个数量级,维持在10-6-10-7A·cm-2.而镀薄银钢板则因为银层较薄存在微孔,使得部分不锈钢基体外露,形成腐蚀电池而更易于腐蚀.     

聚硅氧烷/液晶复合膜的制备及其血液相容性研究

以含氢硅油和乙烯基硅油为基质,在氯铂酸催化下与胆甾醇油烯基碳酸酯液晶共混交联成一定强度的聚硅氧烷／液晶复合膜。借助偏光显微撞观察了不同液日含量在材料表面的状态,通过动态凝血实验、血小板粘附与变形实验、溶血实验等研究材料表面形态与血液相容性的关系。结果表明,含液晶２０％、３０％的液晶膜具有优良的抗凝血性能。     

表面改性聚丙烯的血液相容性研究进展

聚丙烯具有价格低廉、无毒、易于加工等优点,使其在许多领域得到广泛的应用。但是聚丙烯自身有较强的疏水性,与血液相接触时,血浆蛋白会在材料表面大量吸附,诱发血小板的粘附和聚集,从而造成凝血和溶血的发生。在生物医用材料的应用过程中,血液相容性是限制材料能否长期应用的关键因素。本文综述了表面改性法提高聚丙烯血液相容性的研究现状、表面改性方法和常用的大分子单体,并分析了当前聚丙烯表面改性研究存在的问题,展望了具有良好血液相容性聚丙烯的发展前景。     

基于多巴胺自聚合及肝素固定改善钛的血液相容性

利用多巴胺自聚合及肝素固定的方法对纯钛进行表面修饰, 以改善其血液相容性. 采用水接触角测量、 X射线光电子能谱(XPS)和甲苯胺蓝法(TBO)等方法对所修饰的材料进行了表征. 采用溶血实验检测了材料的溶血性能, 并结合活化部分凝血活酶时间(APTT)测试和血小板黏附实验对所修饰材料的血液相容性进行了评价. 结果表明, 多巴胺能够在钛表面实现自聚合, 肝素可以共价接枝在聚多巴胺层上, 经肝素修饰后的材料的表面亲水性显著提高, 而且具有较低的溶血率, APTT时间显著延长, 血小板的黏附数量和被激活程度也显著降低. 因此, 纯钛经多巴胺自聚合以及肝素接枝修饰后的血液相容性得到了显著改善, 有望成为具有抗凝血功能的新型心血管植入材料.     

天然海水中聚吡咯膜的防微生物附着及防腐蚀性能

采用恒电流法在316 L不锈钢电极表面合成聚吡咯(PPy), 通过开路电位、 生物显微镜(BM)、 Tafel极化曲线及电化学交流阻抗(EIS)研究了聚吡咯防止微生物附着及防腐蚀特性. 研究表明, 沉积聚吡咯的316 L不锈钢电极浸泡在天然海水中(0~20 d), 开路电位基本保持不变, 表明电化学合成的聚吡咯膜有良好的防止微生物附着能力, 并通过生物显微镜进行了验证, 且在浸泡的过程中其腐蚀电流密度维持在10^-7 mA/cm², 表现出良好的防腐蚀特性; 浸泡50 d后, 其防腐蚀效率仍高达97.45%. 因此, 电化学合成的聚吡咯具有优异的防止微生物附着和防腐蚀特性.     

纳米Eu2O3/硫酸酯化壳聚糖杂化材料的制备及其抗凝血性能研究

利用表面接枝的方法制备了纳米Eu2 O3/硫酸酯化壳聚糖杂化材料,并用IR,TG和SEM等方法对产物进行了表征,结果表明硫酸酯化壳聚糖接枝在了经过活化后的纳米氧化物表面,细胞毒性实验证明材料具有较低的细胞毒性和较好的细胞相容性.抗凝血实验说明材料具有良好的抗凝血性能.表面接枝方法提高了壳聚糖类化合物的抗凝作用,弥补了比...     

溶胶-凝胶法制备改性TiO2纳米薄膜及其防腐蚀性能

应用溶胶-凝胶法和浸渍提拉技术在316L不锈钢表面分别制备TiO2纳米膜和 B-Fe-Ce改性的TiO2纳米膜. 采用场发射扫描电子显微镜(FE-SEM)、原子力显微镜(AFM)、拉曼光谱法和能量分散谱(EDS)对薄膜进行表征,通过电化学阻抗谱(EIS)和动电位阳极极化曲线的测试考察薄膜的耐蚀性及对不锈钢的保护性能. 结果表明:两种纳米薄膜均含锐钛矿型的TiO2纳米颗粒,纯TiO2纳米膜与改性后的纳米膜中颗粒直径分别约为15和10 nm. TiO2/316L不锈钢和 B-Fe-Ce-TiO2/316L不锈钢膜电极浸泡在0.5 mo.lL-1 NaCl溶液后,后者的电化学反应电阻较大,动电位阳极极化曲线的稳定钝化区较宽,击穿电位更高,说明改性的纳米膜的耐蚀性及其保护性能更好.     

TiO_2/316L不锈钢薄膜电极在NaCl溶液中的耐腐蚀性能

应用sol gel法和提拉技术于 316L不锈钢表面构筑纳米TiO2薄膜,再经水热后处理以消除膜中的细小龟裂.SEM和XRD技术表征膜的形貌和厚度,线性极化法分别考察膜厚度、pH、和Cl浓度对纳米膜电极耐腐蚀性能影响.电化学交流阻抗检测纳米TiO2膜在 0. 5mol/LNaCl溶液中的阻抗随浸泡时间的变化,光电子能谱技术测定了经浸泡 1008h后的纳米膜中各元素相对百分含量和价态.结果表明:在中性或碱性条件下,厚度为 375~464nm的纳米膜其耐腐蚀性随浸泡时间的延长呈现初期增加而后稳定,浸泡 48h后腐蚀电流较之浸泡初期降低 2个数量级,耐腐蚀电阻增加 2个数量级,在浸泡 1 008h内没有发现腐蚀的产物,Fe是以原子态扩散到膜中.     

Structure,hydrophilicity and corrosion resistance of sol–gel derived Ag-containing TiO2 film on plasma nitrided 316L stainless steel

Pure and Ag-containing TiO₂ films (Ag/Ti = 3.3 at.%) are coated on plasma nitrided 316L stainless steel by sol–gel method for biomedical applications. The addition of Ag does not cause obvious change in TG–DSC curves of the dried gels. The rough surface generated by plasma nitriding and the addition of Ag improve structural integrity of the TiO₂ films. X-ray diffraction reveals N loss and oxidation of the nitride layer during calcination treatment, and peaks of Ag or its oxides are not detected. X-ray photoelectron spectroscopy analysis indicates that Ag presents as metallic state in the film. Water contact angles of the coating samples decrease with UV irradiation treatment. The potentiodynamic polarization tests in a Ca-free Hank’s balanced salt solution show that the TiO₂ coated samples have decreased corrosion resistance due to N loss and oxidation of the nitride layer. The methods for crystallization of TiO₂ gel layers with minimized or avoided structural changes of the nitride layer will be tried in order to improve corrosion resistance of the duplex treated 316L stainless steel.     

Preparation,characterization and in vitro anticoagulation of emodin-eluting controlled biodegradable stent coatings

In this study, emodin-eluting poly(lactide-co-glycolide) (PLGA) coating stents and emodin-loaded PLGA films were prepared to explore the potential application of emodin-eluting stent for treating cardiovascular disease. Fourier transform infrared spectra (FTIR) showed all characteristic adsorption peaks of emodin in emodin-loaded PLGA film in comparison to pure emodin. The balloon expansion experiment and surface morphology observation suggested that the integrated emodin-eluting coatings were successfully obtained on the stainless steel surfaces and the coatings had the ability to withstand the strains imparted during balloon experiment. The drug release profile revealed the nearly linear release curve without obvious burst release for different doses of emodin-eluting stents. As compared with stainless steel and PLGA, in vitro platelet adhesion and APTT (activated partial thromboplastin time) tests revealed better blood compatibility of emodin-eluting stent. In conclusion, the results of the present study showed that the emodin-eluting stent has a potential application for treating cardiovascular disease.     

Blood compatibility of surface modified Si incorporated carbon nanotubes film

There is an increasing interest in developing novel film to improve the biocompatibility of cardiovascular implants. In this study, carbon nanotubes (CNT) film was synthesized by on the Si wafers using thermal chemical vapor deposition. The structure, surface properties as well as surface biomedical compatibility were evaluated using different characterization techniques. The contact angles of water on Si, stainless steel and CNT film were 33.7°, 72.4° and 105.1°, respectively. In vitro platelet adhesion experimental results demonstrated that the CNT film significantly reduced thrombogenicity by minimizing the platelet adhesion, activation and aggregation, compared to Si wafer and 316L stainless steel. The hydrophobic properties were determined to be factor contributing to the improved haemocompatibility.     

Fabrication of alternating polycation and albumin multilayer coating onto stainless steel by electrostatic layer-by-layer adsorption

Multilayer films consisting of polyethylenimine (PEI) and albumin were successfully prepared on biomedical 316L stainless steel surface via electrostatic self-assembly of the PEI and albumin. The process of electrostatic self-assembly of PEI/albumin was monitored by125I radiolabeling, electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM). The EIS data revealed that the multilayer coating was stable in Tris-HCl (pH 7.35) buffer solution for 21 days. 125I radiolabeling experiments indicated that less than 10% albumin was eluted by PBS in 45 days. Static platelet adhesion experiments indicated that the PEI/albumin deposited on stainless steel could resist platelet adhesion effectively. Such an easy processing and shape-independent method may have good potential for surface modification of cardiovascular devices.     

Improved blood compatibility of rapamycin-eluting stent by incorporating curcumin

This paper dealt with improving the blood compatibility of the rapamycin-eluting stent by incorporating curcumin. The rapamycin- and rapamycin/curcumin-loaded PLGA (poly(d,l-lactic acid-co-glycolic acid)) coatings were fabricated onto the surface of the stainless steel stents using an ultrasonic atomization spray method. The structure of the coating films was characterized by Fourier transform infrared spectroscopy (FTIR). The optical microscopy and scanning electron microscopy (SEM) images of the drug-eluting stents indicated that the surface of all drug-eluting stents was very smooth and uniform, and there were not webbings and "bridges" between struts. There were not any cracks and delaminations on stent surface after expanded by the angioplasty balloon. The in vitro platelet adhesion and activation were investigated by static platelet adhesion test and GMP140 (P-selection), respectively. The clotting time was examined by activated partially prothromplastin time (APTT) test. The fibrinogen adsorption on the drug-loaded PLGA films was evaluated by enzyme-linked immunosorbent assay (ELISA). All obtained data showed that incorporating curcumin in rapamycin-loaded PLGA coating can significantly decrease platelet adhesion and activation, prolong APTT clotting time as well as decrease the fibrinogen adsorption. All results indicated that incorporating curcumin in rapamycin-eluting coating obviously improve the blood compatibility of rapamycin-eluting stents. It was suggested that it may be possible to develop a drug-eluting stent which had the characteristics of not only good anti-proliferation but also improved anticoagulation.     

Self-assembled monolayers of alkanoic acids on the native oxide surface of SS316L by solution deposition

Stainless steel 316L is a widely used biomaterial substrate whose biocompatibility could be improved by surface modification. As a first step in this process, self-assembled monolayers of octanoic acid, octadecylcarboxylic acid, 16-hydroxyhexadecanoic acid, 12-aminododecanoic acid, and 1,12-dodecane dicarboxylic acid have been formed on the native oxide surface of stainless steel 316L by a simple, one-step solution deposition method. The ordering, close-packing, and coverage of the monolayers formed were characterized by diffuse reflectance infrared spectroscopy, contact angle measurements, and atomic force microscopy. The same procedure was applicable for all long alkyl chain carboxylic acids. This process formed chemically and mechanically stable monolayers. These carboxylic acids formed a bidentate bond with the stainless steel substrate. Robust chemical attachment of the acids to stainless steel through a simple process provides a stepping stone to improving the biocompatibility of stainless steel 316L.