316L不锈钢表面聚氨酯多孔涂层的制备及其生物性能研究

利用湿法相转化原理在316L不锈钢表面制备聚氨酯涂层时，空气湿度和溶液浓度是影响涂层形貌的两个主要因素．涂层表面形貌的观察结果表明：空气湿度增大或者溶液浓度减少，都有增大涂层表面孔径的趋势，而且可以加深孔的深度．通过控制空气湿度和溶液浓度，孔径可以在几个微米到30多个微米的范围内变化．通过亲疏水性测量、血小板粘附试验和动态凝血试验考察了涂层的血液相容性．以316L不锈钢作为参照组进行对比分析，结果可知：PU多孔涂层表面为超疏水性，明显降低了血小板在材料表面的粘附，延长了动态凝血时间，表现出良好的血液相容性．     

316L不锈钢表面聚氨酯多孔涂层的制备及其生物性能的研究

利用湿法相转化原理在316L不锈钢表面制备聚氨酯涂层时，空气湿度和溶液浓度是影响涂层形貌的两个主要因素。涂层表面形貌的观察结果表明：空气湿度增大或者溶液浓度减少，都有增大涂层表面孔径的趋势，而且可以加深孔的深度。通过控制空气湿度和溶液浓度，孔径可以在几个微米到三十多个微米的范围内变化。通过亲疏水性测量、血小板粘附试验和动态凝血试验考察了涂层的血液相容性。以516L不锈钢作为参照组进行对比分析，结果可知：PU多孔涂层表面为超疏水性，明显降低了血小板在材料表面的粘附，延长了动态凝血时间，表现出良好的血液相容性。     

316L不锈钢支架表面EVAL涂层的制备及性能研究

采用超声-喷涂沉积的方法,在316L不锈钢表面制得聚乙烯-乙烯醇涂层。利用原子力显微镜、接触角测量仪及扫描电镜对涂层表面形貌及性能进行研究。结果表明,316L不锈钢基体、S-EVAL涂层和USEVAL涂层的表面粗糙度Ra分别为123.677,14.994和2.830 nm。S-EVAL涂层和US-EVAL涂层表面接触角分别为75.6和74.3°,均小于316L不锈钢基体接触角。超声-喷涂沉积US-EVAL涂层血小板粘附量最少。     

涂层工艺对聚碳酸亚乙酯载药涂层性能和体外释放动力学的影响

为了考察不同涂层工艺对冠脉支架涂层的影响,分别采用手动浸涂和自动超声喷涂法在316L不锈钢冠脉支架基体表面制备含雷帕霉素的聚碳酸亚乙酯(PEC)涂层。首先对PEC进行了凝胶渗透色谱(GPC)、差示扫描量热(DSC)以及拉伸实验测试,初步证明其物理化学性质适合作支架可降解涂层材料。然后用扫描电子显微镜(SEM)、原子力显微镜(AFM)、接触角测定仪、球囊扩张法等对涂层表面的形貌、亲水性以及涂层和支架基体的结合力进行分析,并在PBS(pH=7.4)模拟体液中测试上述两种工艺方法制备的药物洗脱支架体外药物释放动力学曲线。结果表明,上述两种方法制备的药物涂层在微观结构、亲水性以及与支架的结合力方面存在一定差异,药物释放速率和释放趋势也有所不同,超声喷涂法制备的药物洗脱支架释放速率和释放趋势较稳定。     

PLGA携载紫杉醇涂层包被TiNi合金的表面特性与生物性能

系统研究了PLGA携载紫杉醇包被TiNi合金的表面特性与生物性能。采用原子力显微镜(AFM)和X射线光电子能谱(XPS)研究了药物涂层的表面形貌及化学成分;采用高效液相色谱(HPLC)研究了在pH为7.4的PBS溶液中紫杉醇从TiNi合金表面涂层中释放特性,并通过血小板粘附试验研究了药物涂层的血液相容性。试验结果表明经涂覆后TiNi合金表面化学组成及结构随着载药量的增加而改变。紫杉醇在涂层降解初期释放较快,随着时间的延长,累积释放量增加缓慢。血小板粘附试验表明载药量为0%、10%、20%和30%时涂膜样品表面血小板粘附数量均小于未涂膜样品表面。而随着载药量的增加,涂膜样品表面粘附的血小板数量增加,血小板变形严重,当载药量为30%时,血小板出现明显的聚集现象。     

冠脉支架表面聚醚聚氨酯涂层的制备工艺及性能研究

利用浸涂方法在不锈钢冠脉支架表面制备出聚醚聚氨酯涂层.针对冠脉支架复杂的网状结构,对制备工艺进行了研究.结果表明,该涂层具有完整无缺陷的表面形貌,低的表面粗糙度,满足要求的力学性能,并保持了聚醚聚氨酯的微相分离结构,从而保证了良好的血液相容性.本项研究为探索简便而有效的支架表面涂层制备工艺奠定了基础.     

工业纯钛表面高能喷丸对溶胶-凝胶法制备羟基磷灰石涂层的影响

将表面抛光和高能喷丸处理的工业纯钛在8mol/L NaOH溶液中处理后,采用溶胶-凝胶(sol-gel)法在其表面制备羟基磷灰石(HAP)涂层.用扫描电镜(SEM)、X射线衍射仪(XRD)对涂层的表面、截面形貌及成份进行了分析;用拉伸试验机测试了涂层与基体之间的结合强度;动态凝血实验测试了涂层的血液相溶性;探讨了高能喷丸工艺对钛基体及涂层的影响.结果表明,通过sol-gel法,在两种基体表面制备了HAP涂层;高能喷丸工艺增加了基体的表面粗糙度和表面积,利于HAP的涂覆.提高了涂层与基体间的结合力,由抛光处理的10MPa提高到喷丸处理的30MPa;喷丸基体表面的涂层具有更好的抗凝血性.     

可降解镁合金表面载药涂层的制备和性能

在可降解AZ31B镁合金心血管支架表面成功制备了携带雷帕霉素的聚乳酸-聚三亚甲基碳酸酯(PLA-PTMC)共聚物涂层,评价了涂层的表面形貌、降解性能、血液相容性和药物释放性能.结果表明,PLA-PTMC共聚物作为载药涂层具有良好的柔韧性,表面均匀、光滑,降解周期超过1个月,血液相容性良好.涂层具有缓释雷帕霉素的功能,释药周期超过1个月,可在内膜增生期内有效抑制支架植入后再狭窄的发生,满足冠脉支架表面载药层的使用要求.     

溶胶-凝胶法制备TiO2与SiO2-TiO2薄膜对医用NiTi合金的表面改性

采用溶胶－凝胶法制备TiO2与SiO2-TiO2薄膜，对医用NiTi合金进行表面改性处理，利用X射线衍射（XRD）、原子力显微镜（AFM）、划痕试验和电化学腐蚀试验等手段系统研究了薄膜结构、形态及性能。通过动态凝血时间和血小板粘附的测量研究和评价了薄膜的体外血液相容性。结果表明，在一定范围内，较高热处理温度有利于薄膜与基体间的结合强度和耐腐蚀性的提高；NiTi合金表面镀TiO2与SiO2-TiO2薄膜后，其血液相容性明显提高。     

超声雾化喷涂法制备抗血小板膜糖蛋白单克隆抗体洗脱支架及其生物相容性研究

采用超声雾化喷涂法制备抗血小板膜糖蛋白单克隆抗体洗脱支架。以涂层均匀度和接触角大小来优化壳聚糖单抗涂层参数,在外层喷涂一层左旋聚乳酸作为屏蔽层控制单抗SZ-21的释放速度。通过溶血率检测涂层支架的血液相容性;MTT实验和细胞粘附实验考察涂层支架的细胞相容性。对支架表面涂层进行SEM和EDS分析,结果表明,聚合物和单抗成功涂层到支架表面,且涂层均匀。涂层支架溶血率低于国家标准的5%,涂层支架对血管内皮细胞没有产生明显的毒副作用;涂层支架有良好的细胞相容性,利于细胞在支架上生长。具有屏蔽层的单抗SZ-21涂层支架较没有涂层屏蔽层的单抗SZ-21涂层支架的SZ-21释放明显成缓慢释放,无暴释现象。     

Effect of micro-arc oxidation surface modification on the properties of the NiTi shape memory alloy

In this paper, the effects of micro-arc oxidation (MAO) surface modification (alumina coatings) on the phase transformation behavior, shape memory characteristics, in vitro haemocopatibility and cytocompatibility of the biomedical NiTi alloy were investigated respectively by differential scanning calorimetry, bending test, hemolysis ratio test, dynamic blood clotting test, platelet adhesion test and cytotoxicity testing by human osteoblasts (Hobs). The results showed that there were no obvious changes of the phase transformation temperatures and shape memory characteristics of the NiTi alloy after the MAO surface modification and the coating could withstand the thermal shock and volume change caused by martensite-austenite phase transformation. Compared to the uncoated NiTi alloys, the MAO surface modification could effectively improve the haemocopatibility of the coated NiTi alloys by the reduced hemolysis ratio, the prolonged dynamic clotting time and the decreased number of platelet adhesion; and the rough and porous alumina coatings could obviously promote the adherence, spread and proliferation of the Hobs with the significant increase of proliferation number of Hobs adhered on the surface of the coated NiTi alloys (P?<?0.05).     

Preparation and characterization of rapamycin-loaded PLGA coating stent

In this study, using polylactic acid-co-glycolic acid (PLGA) with a molecular weight of 95,800 Da as drug carrier, three dose (low, moderate, high) rapamycin-eluting stents and the corresponding coating films were prepared. The pre- and post-expansion morphology of the rapamycin-eluting stent was examined by scanning electron microscopy (SEM), indicating that the coating was very smooth and uniform. The coating had the ability to withstand the compressive and tensile strains imparted without cracking from the stent during expansion process. There were many voids on stent coating surface after released for 18 days in release medium. The thermodynamics data of the stent coating film measured by differential scanning calorimetry (DSC) showed a lack of measurable solubility of rapamycin in the PLGA matrix. The release behavior of rapamycin from stent surface had a two phase release profile with a burst release period of about 2 days, followed by a sustained and slow release phase. The mass loss behavior of PLGA appeared linear throughout most of the degradation period, corresponding to an approximately constant mass loss rate. The platelet adhesion tests showed that the rapamycin-eluting films may have a good blood compatibility compared with control samples. Take into these results account, this novel rapamycin-eluting may be a good candidate to resolve in-stent restenosis.     

Effect of nitrogen on blood compatibility of nickel-free high nitrogen stainless steel for biomaterial

The aim of this paper was to study the effect of nitrogen content on blood compatibility including platelet adhesion and kinetic clotting time of nickel-free high nitrogen stainless steel (HNS), also in comparison with a conventional austenitic stainless steel AISI 317L. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface chemical composition. The surface wettability and surface free energy (SFE) of these materials were characterized by water contact angle (WCA) measurement to analysis the relationship between surface properties and blood compatibility. Kinetic clotting time was used to evaluate the blood coagulation for these materials and platelet adhesion was assessed by scanning electron microscopy (SEM). The results showed that more platelets adhered on the surface of 317L stainless steel than that on HNS, and with the increase of nitrogen content, the amount of adherent platelets was further decreased on the surface of HNS. Kinetic clotting time results also showed the increased nitrogen content extended the initial clotting time of HNS. The results of surface properties also explained the effect of nitrogen on blood compatibility by traditional theory of SFE and interfacial energy.     

Ti-Ta-O涂层的抗凝血性研究

利用磁控溅射技术合成了Ti-Ta-O薄膜涂层,采用体外血小板粘附试验,动态凝血时间测定以及动物体内试片埋植试验等评价方法,对涂层的抗凝血特性进行了研究;并采用Tauc法研究了涂层的禁带宽度,研究结果表明,Ti-Ta-O薄膜涂层具有良好的抗凝血特性以及禁带宽度为3．2eV的半导体特性,此外,探讨了Ti-Ta-O涂层的抗凝血机理,并提出材料的半导体特性是影响Ti-Ta-O涂层抗凝血特性的主要原因之一。     

Glutaraldehyde proteinated surfaces: blood compatibility

This paper reports our attempts to crosslink low molecular weight proteins namely trypsin and insulin using glutaraldehyde on polycarbonate surface and to evaluate how such surfaces may affect the blood compatibility of the polymer, by studying the interfacial energies of the modified polymer surface using advancing contact angle technique. The plasma recalcification time and platelet adhesion studies were also carried out. It has been observed that such low molecular weight proteins retard clotting.     

Blood compatibility of zinc–calcium phosphate conversion coating on Mg–1.33Li–0.6Ca alloy

Magnesium alloys as a new class of biomaterials possess biodegradability and biocompatibility in comparison with currently used metal implants. However, their rapid corrosion rates are necessary to be manipulated by appropriate coatings. In this paper, a new attempt was used to develop a zinc-calcium phosphate (Zn-Ca-P) conversion coating on Mg-1.33Li-0.6Ca alloys to increase the biocompatibility and improve the corrosion resistance. In vitro blood biocompatibility of the alloy with and without the Zn-Ca-P coating was investigated to determine its suitability as a degradable medical biomaterial. Blood biocompatibility was assessed from the hemolysis test, the dynamic cruor time test, blood cell count and SEM observation of the platelet adhesion to membrane surface. The results showed that the Zn-Ca-P coating on Mg-1.33Li-0.6Ca alloys had good blood compatibility, which is in accordance with the requirements for medical biomaterials.     

In vitro blood compatibility of poly (hydroxybutyrate-co-hydroxyhexanoate) and the influence of surface modification by alkali treatment

In vitro blood compatibility of poly (hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) was evaluated in comparison with poly (L-lactic acid) (PLLA) by a haemolysis assay, in vitro platelet adhesion test and coagulation measurements including plasma recalcification time (PRT), plasma prothrombin time (PT) and kinetic clotting time. The results showed that PHBHHx exhibited better blood compatibility than PLLA. Furthermore, PHBHHx film was modified by NaOH treatment to improve the surface hydrophilic property and the influence of the surface modification on the blood compatibility was investigated. Surface properties including hydrophilic property, surface appearance and functional groups were characterized by water contact angle measurement, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the hydrophilic property of PHBHHx film was obviously improved by the NaOH treatment. It was also shown that the NaOH treatment could significantly enhance the blood compatibility of PHBHHx by prolonging PRT, PT, and kinetic clotting time and decreasing platelet activation. It is thought that the improvement in the hydrophilic property mainly contributes to the enhancement of blood compatibility.     

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.     

Reduced platelet adhesion and blood coagulation on cross-linked albumin films

Surface-induced thrombosis is a major complication associated with blood-contacting biomaterials. Cross-linked albumin films possessing native albumin characteristics such as resistance to cell adhesion and drug binding ability are available for improving the blood compatibility of biomaterial surfaces. In the present study, we aimed to evaluate the blood compatibility of cross-linked albumin films. Platelet adhesion analysis showed that albumin film coated substrates exhibited very low platelet adhesion, and platelet adhesion was further suppressed by loading the antiplatelet drug, cilostazol, into the film. Monitoring the coagulation process of whole blood using a coaxial-cylinder rotational viscometer showed that the initial time of coagulation in albumin film coated cylinders was delayed compared with that in uncoated cylinders, suggesting that activation of the intrinsic coagulation cascade was reduced on the albumin film coated surface. Thus, surface coating with cross-linked albumin films is a promising approach to conferring biomaterials with antithrombogenic surfaces due to the resistance to platelet adhesion and the antiplatelet drug-releasing capability afforded by the films.