退火对镀钽TiNi合金微观组织结构和血液相容性的影响

采用原子力显微镜(AFM)和X射线衍射分析(XRD)研究了退火处理对TiNi合金钽镀层微观组织结构的影响,研究表明采用多弧离子镀在TiNi合金表面沉积得到了β-Ta镀层,经退火处理后,钽镀层的表面粗糙度增加,亚稳定的β-Ta相完全转变为稳定的α-Ta相.采用血小板粘附试验研究了退火对镀钽TiNi合金血液相容性的影响.发现经过退火处理后血小板粘附数量明显降低,血小板没有发生聚集和变形,只有少数长出了伪足,即血小板基本未被激活,说明退火改善了镀钽TiNi合金的血液相容性.     

镁合金支架双重可控释放涂层的制备及药物释放性能研究

在镁合金支架材料WE42表面制备了双重可控腐蚀和药物缓释涂层,并对其药物释放性能进行了研究.DSC研究表明紫杉醇均匀分散在PLGA体系中.药物释放实验表明,PLGA可使紫杉醇长期持续释放,突释较弱,释放是由扩散-降解控制.随载药膜中PEG分子量和含量的增加,药物释放率增加.外层明胶涂层能有效降低药物释放率,延长药物释放时间.     

聚乳酸/辣椒素复合载药薄膜的制备及药物释放

利用静电纺丝法和溶液法分别制备了具有微纳米纤维结构、串珠结构和较密实结构的聚乳酸/辣椒素复合载药薄膜(分别称为薄膜Ⅰ、薄膜Ⅱ和薄膜Ⅲ)。研究了不同载药量(5%、10%和15%,质量分数)和不同微结构对药物释放行为的影响。药物释放研究表明:PLA/Cap复合载药薄膜的微结构和载药量都对药物释放行为有重要的影响。当载药量为5%和10%(质量分数)时,药物释放行为主要受载药薄膜的微结构影响,释放速度由快到慢为:薄膜I、薄膜Ⅱ、薄膜Ⅲ;随着载药量的增加药物释放速度加快,且3种载药薄膜的辣椒素释放速度之间的差别减小。当载药量达15%(质量分数)时,载药量对药物释放行为的影响较微结构的影响更加显著,3种载药薄膜的药物释放行为接近。     

地塞米松-乙交酯丙交酯共聚物作为药物洗脱支架的涂层研究

采用溶液浇注法制备了以乙交酯丙交酯共聚物(PLGA)为载体、地塞米松为药物的载药薄膜。傅立叶红外光谱(FT-IR)结果显示地塞米松被有效地分散在PLGA中;水接触角测试结果表明相比于PLGA薄膜,地塞米松的引入增加了薄膜的亲水性。载药薄膜的体外药物释放行为表明地塞米松存在突释现象,6d后呈现出较好的线性释放特征。体外生物学评价表明装载地塞米松的PLGA表面既对血小板的粘附与激活具有一定的抑制作用,又显著地抑制平滑肌细胞的粘附与增殖。采用超声雾化喷涂法制备了地塞米松药物洗脱支架,扫描电镜观察表明支架表面涂层光滑均匀且连续,支架撑开后没有产生剥落和裂纹。     

醋纤基载药纳米纤维的制备及性能研究

采用静电纺丝制备了载药量分别为10%、20%和30%的单层结构醋酸纤维素(CA)载药纳米纤维膜、载药量为20%的多层结构聚乳酸(PLA)/CA载药/PLA载药纳米纤维膜,药物选用抗菌药单宁(TA)、抗凝血药阿司匹林(AS)和姜黄素(CM),研究了载药膜的体外释药性能,同时以血小板粘附、改良振荡烧瓶法对三种药物的药物活性进行了评价。结果表明:释药性能测试发现,载药量多的纳米膜释药速率更快,多层结构均延缓了释药速率,且PLA层越厚释药速率越低。CM、AS的加入使得血小板大面积团聚现象消失,TA的加入,使纳米膜对大肠杆菌和金黄葡萄球菌的抑菌率分别从24.2%和23.2%增加至90%和92%以上。药物仍保留活性。     

冠脉支架表面载药涂层的制备和性能

采用溶液聚合法制备了改性的聚甲基丙烯酸树脂,作为支架表面载药涂层的药物载体聚合物.采用浸涂法制备了不锈钢基体表面聚合物及聚合物载药涂层,并利用红外光谱及核磁共振波谱分析了所制备共聚物的成分,并评价了物理性能、生物稳定性能以及药物的释放性能.结果表明,所制备的涂层具有较好的生物稳定性,甲基丙烯酸和甲基丙烯酸丁酯的加入提高了聚合物的物理性能,尤其是涂层与金属基体的结合力所制备的药物释放涂层具有缓释紫杉醇的功能,其释放周期超过15 d.聚甲基丙烯酸树脂携带紫杉醇的载药涂层在生物稳定性、物理性能及药物释放性能方面满足冠脉支架的表面涂层的使用要求.     

他克莫司-聚三亚甲基碳酸酯药物洗脱支架涂层研究

以表面溶蚀性可降解聚合物聚三亚甲基碳酸酯（PTMC）为载体,分别采用超声雾化喷涂技术和溶液浇注法制备了以PTMC为涂层载体的他克莫司药物洗脱支架和载药薄膜。傅里叶红外光谱（FT-IR）结果显示他克莫司分散在PTMC中。扫描电子显微镜观察支架撑开后的药物涂层保持连续均匀,没有开裂和剥落。他克莫司洗脱支架的药物释放行为与Weibull模型的相关性最高。体外血小板粘附和平滑肌粘附、增殖实验表明包载他克莫司的PTMC表面具有显著地抑制血小板粘附和平滑肌增生的作用。     

电化学抛光时间对常规和超细晶TiNi合金生物活性的影响

研究了电化学抛光时间(60、180s)对常规和超细晶TiNi合金表面形貌与生物活性的影响。结果表明,电化学抛光时间从60s增加到180s时,常规Ti-Ni合金表面纳米尺度蚀坑数量增多,但仅轻微提高了其生物活性(模拟体液中Ca-P层的生长速率),而超细晶TiNi合金表面纳米蚀坑数量大幅减少,生物活性虽大幅降低,但仍显著高于常规TiNi合金。结果表明,除了增加纳米尺度蚀坑形貌外,组织超细化也是提高生物活性的一个有效方法。     

高压静电抗溶剂法制备甲氨蝶呤-聚乳酸复合微球的研究

基于超临界CO2技术制备的甲氨蝶呤纳米粒为小分子模型药物,采用高压静电抗溶剂法制备甲氨蝶呤-聚乳酸复合微球。用扫描电镜(SEM)、傅立叶红外光谱仪(FT-IR)对该载药复合微球进行表征,并研究其载药量、包封率和药物释放曲线。实验结果表明,甲氨蝶呤-聚乳酸复合微球表面光滑,粒径分布范围在10～50μm之间;FT-IR表明,在高压静电抗溶剂过程中聚乳酸化学结构无变化,有利于其作为药物载体;随着理论载药量增加(2.5%、5%和10%),包封率减少(18.0%、7.1%和2.3%);甲氨蝶呤从聚乳酸微球中释放具有长效缓释的性能,无突释效应。     

载紫杉醇聚乳酸-羟基乙酸纳米粒的体外释药研究

以生物可降解材料聚乳酸-羟基乙酸(PLGA)为载体制备了载紫杉醇纳米粒,重点考察了纳米粒的体外释放特性.采用乳化-溶剂挥发法制备了载紫杉醇PLGA纳米粒,其平均粒径为200nm,载药量为21%,包封率为89.44%;体外释药符合Higuchi方程:Q=3.8796t1/2+30.4649(r=0.9397),同时载紫杉醇纳米粒具有一定的缓释作用.     

镀钽TiNi形状记忆合金表面的XPS分析

采用多弧离子镀的方法在Ti 50.6%(原子分数)Ni形状记忆合金表面沉积了钽镀层。通过X射线光电子能谱(XPS)剖面分析发现TiNi合金表面钽镀层厚度均匀,并且在镀层与基体之间形成一薄层过渡层。将镀钽TiNi合金曝露于空气中后,通过XPS的全谱和高分辨谱图对其表面的成分和价态分析发现,镀钽层表面由于钽在空气中自然氧化形成了一层很薄的钽的氧化膜,最表面为高价钽的氧化物(Ta2O5),次表面为低价钽氧化物的混合物TaO2、TaO和TaOx(x<1)。     

Surface Composition and Corrosion Property of TiNi Alloys Coated with Tantalum Films

Multi-arc ion plating method was employed to coat TiNi alloys with Ta in order to improve radiopacity and corrosion resistance property. The surface composition, corrosion resistance property and Ni ions release amount of TiNi alloys coated with Ta films compared with TiNi alloys, are investigated by means of X-ray photoelectron spectrometry (XPS), electrochemical measurements and atomic absorption spectrophotometry (AAS), respectively. The results show that the coated surface composition is composed of Ta and 0 and the corrosion resistance is improved, whereas the Ni ions release amount of the coated sample is lower than that of the uncoated samples in the whole immersion period, indicating that Ta coating can improve the biocompatibility of TiNi alloys.     

In-vitro release of anti-proliferative paclitaxel from novel balloon-expandable polycaprolactone stents

This report investigated the in-vitro release characteristics of paclitaxel from novel balloon-expandable polycaprolactone stents. Polycaprolactone stents were first manufactured by a lab-made micro-injection molding machine. Paclitaxel and polylactide–polyglycolide (PLGA) copolymer were dissolved in acetonitrile and were coated onto the surface of the stents by a spray coating device, which was designed and built especially for this study. An elution method was utilized to characterize the in-vitro release characteristics of paclitaxel. The high performance liquid chromatography (HPLC) analysis showed that biodegradable stents could provide sustained release of paclitaxel for more than 70 days. Various process parameters that controlled the release rate of paclitaxel were studied. The experimental results suggested that the total period of drug release could be prolonged by adopting 75:25 PLGA copolymers, employing multi-layer coatings, and increasing the drug loading. In addition, the effectiveness of eluted paclitaxel on cell behavior was examined. The results showed that the eluted drug could effectively inhibit the proliferation of smooth muscle cells.     

Effective inhibition of nickel release by tantalum-implanted TiNi alloy and its cyto-compatibility evaluation in vitro

Titanium–nickel (TiNi) shape memory alloy is modified with tantalum (Ta) plasma immersion ion implantation (PIII). Scanning electron microscope (SEM), atomic force microscopy (AFM), inductively coupled plasma mass spectrometry (ICP-MS), methyl-thiazol-tetrazolium (MTT), and cell culture are adopted to evaluate the surface morphology, roughness, Ni release, in vitro cytotoxicity, and cell behavior of TiNi and Ta-implanted TiNi (Ta–TiNi) alloys. Results showed that the surface became rougher and was covered by ordered and uniform grains after Ta implantation. Ni release was averagely inhibited by Ta–TiNi to up to 60% of that in unmodified TiNi alloy within 30 days. MTT assays demonstrated that Ta–TiNi sample allowed greater degree of cell proliferation for both smooth muscle cell and osteoblasts, indicating excellent protection and cyto-compatibility. A negative correlation was observed between Ni release and cell proliferation. Analysis of the cell morphology revealed healthy cells extending on the alloy surface, which indicated that TiNi alloy had good cyto-compatibility despite the initial Ni dissolution, but the implanted Ta would endow traditional TiNi alloy much lower Ni release, improved cyto-compatibility and other potential merits.     

Corrosion and drug release properties of EN-plating/PLGA composite coating on MAO film

The electroless nickel plating/poly(dl-lactide-co-glycolide) composite coating (EN-plating/PLGA composite coating) was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy AZ81 to double control the corrosion and drug release in the hanks' solution. The EN-plating was fabricated on the MAO coating to improve the corrosion resistance by overlaying most pores and micro-cracks on the surface of the MAO film. Meanwhile, a double layered organic poly(dl-lactide-co-glycolide)/paclitaxel (PLGA/PTX) drug releasing coating with a top layered PLGA drug controlled releasing coating on EN plating was prepared to control the drug release rate by adjusting the different lactide: glycolide (LA:GA) ratio of PLGA. Scanning electron microscopy (SEM) and the X-ray powder diffraction (XRD) were used to analyze the morphology and the composition of the EN-plating. The corrosion behavior of the magnesium alloy substrate and the status of the drug in the PLGA matrix were respectively evaluated by Potentiodynamic polarization and Differential scanning calorimetry (DSC). The drug release was determined by ultraviolet–visible (UV–visible) spectrophotometer. EN-plating coating which was composed of compact cauliflower nodules was uniform in size and defect free with no pores or cracks. EN-plating could seal the microcracks and microholes on the outer layer of the MAO coating effectively. The corrosion resistance was improved by preventing the corrosive ions from diffusing to the magnesium alloy substrate. The drug release rate of PTX exhibited a nearly linear sustained-release profile with no significant burst releases.     

紫杉醇在聚甲基丙烯酸树脂中的物化状态

研究了紫杉醇在聚甲基丙烯酸树脂中的化学稳定性、物理分布和物理状态,并分析了其影响因素.结果表明,紫杉醇在复合膜中没有与聚甲基丙烯酸树脂发生化学反应,释放后不改变化学结构;紫杉醇在复合膜中的物理分布受溶剂性质的影响,以四氢呋喃为溶剂,紫杉醇可均匀分布于复合膜中.紫杉醇在复合膜中的存在状态与紫杉醇含量及热处理制度有关.当紫杉醇的含量(质量分数)为10%时,在薄膜中不存在结晶态紫杉醇,当含量大于20%时,出现结晶态紫杉醇.在Tg点附近退火可使薄膜中结晶态紫杉醇的含量增加,从而提高紫杉醇的时效稳定性及其在复合膜中的扩散速度.     

SPS制备TiNi增强镁合金复合材料的微观结构及力学性能

以AZ31镁合金为基体,TiNi形状记忆合金丝为增强体,利用放电等离子烧结法（SPS）制备了TiNi/Mg复合材料,用OM、SEM、EDS对其微观形貌进行表征,并用XRD及DSC研究TiNi丝的相变,同时对该复合材料进行准静态拉伸实验,对其室温及高温力学性能进行研究。结果表明,所制备的TiNi/Mg复合材料中界面处存在Mg、Ti、Ni元素的互扩散现象,并形成宽度约为2 μm的互扩散层;所制备的TiNi/Mg复合材料的高温力学性能高于室温,其中其屈服强度、抗拉强度及弹性模量在100℃时（分别为157 MPa,292 MPa,22 GPa）较室温分别提高了12%、33%和29%,150℃时（分别为143 MPa,251 MPa,20 GPa）较室温分别提高了2%、14%和18%。     

Solventless dry powder coating for sustained drug release using mechanochemical treatment based on the tri-component system of acetaminophen,carnauba wax and glidant

Objective: Solventless dry powder coating methods have many advantages compared to solvent-based methods: they are more economical, simpler, safer, more environmentally friendly and easier to scale up. The purpose of this study was to investigate a highly effective dry powder coating method using the mechanofusion system, a mechanochemical treatment equipped with high compressive and shearing force.Materials and methods: Acetaminophen (AAP) and carnauba wax (CW) were selected as core particles of the model drug and coating material, respectively. Mixtures of AAP and CW with and without talc were processed using the mechanofusion system.Results: Sustained AAP release was observed by selecting appropriate processing conditions for the rotation speed and the slit size. The dissolution rate of AAP processed with CW substantially decreased with an increase in talc content up to 40% of the amount of CW loaded. Increasing the coating amount by two-step addition of CW led to more effective coating and extended drug release. Scanning electron micrographs indicated that CW adhered and showed satisfactory coverage of the surface of AAP particles.Conclusion: Effective CW coating onto the AAP surface was successfully achieved by strictly controlling the processing conditions and the composition of core particles, coating material and glidant. Our mechanochemical dry powder coating method using the mechanofusion system is a simple and promising means of solventless pharmaceutical coating.     

Investigation of the trivalent-chrome coating on 6063 aluminum alloy

In this work, the green trivalent chromium coating on 6063 aluminum alloy surface was made and studied by means of trivalent chromate compound (KCr(SO₄)₂) as inhibitor. The coating was evaluated in 3.5 wt.% NaCl at room temperature using polarization curve, AC impedance spectroscopy (EIS). The results show that the trivalent chromium compounds treated surface presents better corrosion behavior in chloride media than the original material surface. The morphologies and composition and valence state of the coating were examined by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS), respectively. The result indicates that the trivalent chromium chemical conversion coating was made on aluminum alloy surface.     

纳米陶瓷微米高温合金复合涂层组织与性能

采用溶胶-凝胶化学包覆法制备纳米陶瓷微米高温合金复合粉末,用HVOF喷涂技术制备了复合涂层,采用SEM观察和摩擦磨损实验分析了复合粉末和复合涂层的组织和性能.研究表明:复合粉末是以纳米陶瓷为外壳包覆微米级高温合金颗粒核心的核壳式结构;陶瓷壳在喷涂过程中形成液相与高温合金液相熔合,烧结成致密陶瓷相,部分陶瓷在冷却过程中析出结晶体;复合涂层与基体的结合强度为59.2 MPa,摩擦系数为0.766,磨损率比纯高温合金涂层降低了32%.