NiTi合金表面低温等离子体接枝类PEG研究

众所周知表面接枝类聚乙二醇(PEG)可以改善材料的生物相容性.本文研究了氧/二(乙二醇)甲醚低温等离子体条件下NiTi合金表面接枝PEG结构及其性质.经X射线光电子能谱(XPS)、衰减全反射红外光谱(ATR-FTIR)、扫描电镜(SEM)和水接触角的分析和表征,证实沉积的涂层为类PEG结构,表面主要聚集大量(-CH2-CH2-O)n键;与改性前相比,接枝后的NiTi合金亲水性有较大提高.     

聚乙二醇-纤维素接枝物固态相变材料的贮热性能

用化学偶联法,将聚乙二醇(PEG)接枝到纤维素分子链上,制备聚乙二醇-纤维素接枝物。用差示扫描量热(DSC)研究了接枝物的热力学性质。结果表明,PEG-CELL接枝物的相变焓、相变温度与PEG的分子量、PEG的质量百分比有关。当PEG的分子量在2000以下时,制备的接枝物相变焓很低;当PEG的分子量大于4000时。同等分子量情况下,相变焓、相变温度随PEG的质量百分含量减少而下降．所制备的PEG-CELL接枝物为固态相变材料,热滞后性降低,具有很好的热稳定性。     

涤纶材料表面固定水蛭素及其血液相容性研究

利用紫外辐照仪在聚对苯二甲酸乙二醇酯(涤纶,PET)膜表面接枝聚丙烯酸(PET-AA)长链分子,再通过化学方法进一步固定水蛭素,获得的改性表面的X光电子能谱分析表明水蛭素分子被有效地固定在PET表面.改性表面的水接触角降低,亲水性得到改善.体外血小板粘附实验的结果显示,固定了水蛭素的PET薄膜的血液相容性比未改性的PET膜有明显的改善.     

聚砜膜的低温等离子体改性及其在膜式氧合器的应用

采用低温等离子体技术对用于膜式氧合器的聚砜(PSf)膜进行表面改性,通过接枝聚乙二醇(PEG)和肝素以改善其血液相容性.系统研究了接枝的PEG分子量及不同等离子体处理条件对改性效果的影响.研究结果表明,当PEG分子量为6 000,等离子预处理功率为150W,预处理时间为2min,处理气体为氩气(Ar)时,改性效果最佳,接触角明显降低,蛋白吸附显著减少.膜的汽液双侧传输性质测试结果表明,改性后的PSf膜保留了初始膜的气体传输性能,基本达到了医用人工肺材料的标准.     

壳聚糖-白蛋白胶束用于构建血液接触材料表面仿生涂层

血管破裂时,血液系统参与凝血反应,起到止血作用。当植入材料与血液接触时会导致凝血级联响应,因此生物材料的血液相容性至关重要。基于纳米材料的独特性能,本研究中,壳聚糖(CS)在交联剂三聚磷酸钠(TPP)的作用下自组装形成CS-TPP胶束,通过静电相互作用在CS-TPP胶束表面接枝牛血清白蛋白(BSA),使其在CS-TPP胶束表面形成一层蛋白膜,研究其血液相容性。通过调整投料比及反应条件,可实现对胶束尺寸的控制。材料学表征结果显示,CS-TPP-BSA胶束的尺寸均一,形态稳定,分散性良好。随后将CS-TPP-BSA胶束通过多巴胺接枝于材料表面,血液试验证实该胶束涂层能够显著提高血液接触材料的血液相容性。该研究为血液接触生物材料的表面改性提供了一种新的手段。     

聚对苯二甲酸乙二醇酯共价接枝多壁碳纳米管及其表征

通过两步法将聚对苯二甲酸乙二醇酯(PET)分子链共价接枝到多壁碳纳米管(MWCNTs)表面,成功地制备了PET/MWCNTs复合材料。聚丙烯酰氯共价接枝MWCNTs的表面具有多个可反应的酰氯基团,通过与PET端羟基间的反应,以聚丙烯酰氯为中间聚合物层,成功将PET分子链接枝到了碳纳米管表面。采用傅立叶变化红外光谱(FT-IR)、透射电镜(TEM)、核磁(1H-NMR)和热失重分析(TGA)对接枝产物进行了表征,结果表明,PET分子已通过共价接枝的方式接枝到碳纳米管表面,被接枝聚合物的量约为MWCNTs的96%,该接枝聚合物层的存在将有利于多壁碳纳米管与PET树脂间相容性的提高,从而使PET/MWCNTs复合材料的性能得到提高。     

嵌段齐聚物修饰纳米SiO2对PET结晶性能的影响

采用溶液聚合法在纳米 SiO2表面接枝两种不同性质的齐聚物聚乙二醇(PEG)和聚对苯二甲酸乙二酯低聚物(LMPET),通过 FTIR、1 H-NMR、XPS 和 HR-TEM 对其结构形貌进行表征。采用熔融共混制备 PET 纳米复合材料,并利用 DSC 和 XRD 对改性纳米 SiO2对 PET 结晶性能的影响进行研究。结果表明,LMPET 通过 PEG 成功接枝到 SiO2表面,粒径尺寸为40~50 nm;纳米 SiO2可作为成核剂诱导 PET 的结晶提高结晶速率,当添加量为2%(质量分数)时,结晶温度得到明显提高。     

接枝共聚法制备PEG/CDA高分子固-固相变材料及其表征

通过接枝共聚法制备了PEG/CDA复合高分子固一固相变材料,用DSC差示扫描量热法及FTIR对其进行了表征,用正交试验法L9(34)研究了PEG分子量、PEG/CDA的质量比对相变材料储热性能,相变温度等的影响,以及反应时间对接枝反应的影响.结果表明,当PEG相对分子量为6000,PEG/CDA质量比为9:1,接枝反应时间为150 min时,材料的储热性最好.     

磷酰胆碱类似物在有机硅材料表面的常压等离子体引发接枝改性研究

采用He常压辉光放电等离子体(APGDP)处理有机硅薄膜材料表面并引发2-甲基丙烯酰氧乙基磷酰胆碱(MPC)在其表面接枝聚合.通过ATR-FTIR对接枝前后膜表面的结构进行表征分析,确定MPC共价接枝到材料表面.改性后膜表面的接触角由101°下降到54°,在室温下保存15天后仍维持在58°左右,表明接枝MPC后有机硅材料获得高亲水性的表面,并能使这一性质较好地保持.接枝前后膜的力学性质变化不大.体外血小板粘附实验表明,接枝MPC后的材料表面能够显著抑制血小板的粘附和聚集,具有优良的血液相容性,可以作为一种新型医用生物弹性体.     

聚已内酯表面磷酸胆碱仿生改性的血液相容性研究

通过表面原子转移自由基聚合法(SI-ATRP)得到具有不同接枝密度的聚2-甲基丙烯酰氧乙基磷酰胆碱改性的聚己内酯薄片(PCL-g-PMPC)。用衰减全反射红外、扫描电镜及接触角直接或间接地证明表面接枝反应成功;并通过蛋白吸附、血小板粘附及凝血时间对其血液相容性进行了评价。结果表明,利用SI-ATRP法在PCL表面接枝一层具有仿细胞外层膜结构的PMPC能不同程度地提高PCL薄片的血液相容性。     

聚乙二醇/涤纶固固相转变材料化学合成工艺的优化

通过对聚乙二醇/涤沦(PEG/PET)固固相变材料(PCM)化学合成所用的交联体系、工艺条件对相变性能和合成产率的研究,优选出PEG/PET PCM合成工艺.研究表明:采用乙二醇作为交联荆,在140℃下,PEG分子量为10000、PEG/PET比率为95/5时,相变焓可高迭112.02J/g,产率可达到96.70%.     

聚乙二醇改性PET／PBT共混体系研究

本文以廉价易得的聚乙二醇(PEG)作结晶促进剂,利用WAXD、DSC研究了PET/PBT共混体系的结晶行为,并以共混体系结晶熔融峰面积计算PET和PBT各自的结晶度。结果发现,加入PEG可以使共混体系冷结晶峰温明显下降,PEG用量越大,冷结晶峰温越低,结晶速度加快;随着PEG分子量增大,当小于2000或等于2000时,冷结晶峰温随之降低,但当分子量≥6000时,冷结晶峰温随之略有升高;加入PEG,对共混体系中PET和PBT各自结晶的作用不同,二者的结晶度随PEG分子量或用量变化不同。     

Surface grafting of blood compatible zwitterionic poly(ethylene glycol) on diamond-like carbon-coated stent

Blood compatibility is the most important aspect for blood-contacting medical devices including cardiovascular stents. In this study, the surface of nickel–titanium (TiNi) stent was coated with diamond-like carbon (DLC) and then subsequently grafted by using zwitterion (N⁺ and SO₃ ⁻)-linked poly(ethylene glycol) (PEG). We hypothesize that this coupling of zwitterion and PEG may significantly improve blood compatibility of DLC-coated TiNi stent. The surface modified TiNi stents, including PEG-grafted stent (DLC-PEG) and zwitterionic PEG-grafted one (DLC-PEG-N-S) were the main focus on the tests of surface characteristics and blood compatibility. The zwitterionic PEG derivatives were obtained from a series of chemical reactions at room temperature. The results exhibited that as compared to the DLC-PEG, the hydrophilicity was much better with DLC-PEG-N-S and significantly increased atomic percentage of oxygen and nitrogen proved the entity of zwitterions on the surface of DLC-PEG-N-S. Meanwhile, the adsorption of blood proteins such as, human serum albumin (HSA) and fibrinogen was found considerably down-regulated in DLC-PEG-N-S, due mainly to the protein-repellant effect of PEG and zwitterion. Microscopic observation also revealed that as compared with the other substrates without zwitterion, the degree of platelet adhesion was the lowest with DLC-PEG-N-S. In addition, DLC-PEG-N-S retained an extended blood coagulation time as measured by activated partial thromboplastin time (APTT). The present results suggested that surface grafting of zwitterionic PEG derivatives could substantially enhance the blood compatibility of TiNi-DLC stent. In conclusion, anti-fouling properties of PEG and zwitterions are expected to be very useful in advancing overall stent performance.     

聚乙二醇化环维黄杨星D的合成及结构表征

将亲水性的聚乙二醇接枝到环维黄杨星D的氨基侧链上,得到一系列未见报道的聚乙二醇化环维黄杨星D,用IR,1H-NM R对产物进行了表征分析,同时进行了水溶性、水接触角及溶血性实验。结果表明,活化的聚乙二醇被成功地接枝到环维黄杨星D上,使其后者亲水性得到了很大的提高,且对红细胞无破坏作用,有优良的血液相容性,为开发环维黄杨星D新型静脉注射剂提供了实验依据。     

Synthesis of poly(ethylene glycol) functionalized MWNTs and their inclusion complexes with α-cyclodextrin

Poly(ethylene glycol) (PEG) functionalized multiwalled carbon nanotubes (MWNTs), prepared by coupling of isocyanate-decorated MWNTs with PEG of different molecular weights (M _n = 400, 1000, 2000, and 4000 g/mol), were used to form inclusion complexes (ICs) with α-cyclodextrin (α-CD) through the grafted PEG chains being threaded with α-CD rings in aqueous solution. The FTIR, TGA, UV-Vis, and scanning electron microscopy (SEM) techniques were employed to characterize the formed ICs. The ICs formation time was monitored by UV-Vis spectroscopy, and the results indicated that the inclusion interaction between MWNT surface anchored PEG chains and α-CD was dependent on the molecular weight of PEG. The grafted PEG with molecular weights of 4000 and 2000 g/mol, respectively, can form ICs with α-CD, while the grafted PEG with molecular weights of 1000 and 400 g/mol, respectively, are difficult to form ICs with α-CD due to the steric hindrance from nanotubes. The stoichiometry value determined by TGA indicated that the ratio of ethylene glycol (EG) unit to α-CD in the resulted ICs was about 15:1. In addition, the morphology of the ICs was observed by SEM and transmission electron microscopy (TEM).     

Polyethylene glycol-grafted bovine pericardium: a novel hybrid tissue resistant to calcification

Calcification is a frequent cause of the clinical failure of bioprosthetic heart valves fabricated from glutaraldehyde pretreated bovine pericardium (GATBP). An investigation was made of the grafting of different molecular weight polyethylene glycol (PEG 600, 1500, 4000 and 6000) via glutaraldehyde (GA) linkages to bovine pericardium (BP) and of their stability and calcification. The process of the calcification profile was studied by in vitro experiments via incubating pericardial samples in a metastable solution of calcium phosphate. Calcification of bovine pericardium grafted with PEG 6000 was significantly decreased compared to low molecular weight PEG grafts or Sodium dodecyl sulphate- (SDS) and GA-treated tissues. The mechanical properties of these modified tissues after enzyme (Trypsin) digestion and calcification were investigated. The biocompatibility aspects of grafted tissues were also established by monitoring the platelet adhesion, octane contact angle and water of hydration. PEG 6000-grafted tissues retained the maximum strength in trypsin buffer and calcium phosphate solutions. Scanning electron micrographs revealed that the PEG-grafted bovine pericardium had substantially inhibited the platelet–surface attachment and their spreading. It is conceivable that high molecular weight polyethylene glycol-grafted pericardium (a hybrid tissue) may be a suitable calcium-resistant material for developing prosthetic valves due to their stability and biocompatibility. © 1999 Kluwer Academic Publishers     

聚酯－聚醚嵌段共聚物的合成及抗静电性能研究

研究和分析了ＰＥＧ分子量、加料次序、反应时间和温度、物料比例、分散剂和固相缩聚等因素对ＰＥＴ－ＰＥＧ嵌段共聚物分子量和耐水性的影响。合成的嵌段共聚酯醚与ＰＥＴ共混纺丝可以显著改善ＰＥＴ纤维的抗静电性能。     

Plasma-modified and polyethylene glycol-grafted polymers for potential tissue engineering applications

Modified and grafted polymers may serve as building blocks for creating artificial bioinspired nanostructured surfaces for tissue engineering. Polyethylene (PE) and polystyrene (PS) were modified by Ar plasma and the surface of the plasma activated polymers was grafted with polyethylene glycol (PEG). The changes in the surface wettability (contact angle) of the modified polymers were examined by goniometry. Atomic Force Microscopy (AFM) was used to determine the surface roughness and morphology and electrokinetical analysis (Zeta potential) characterized surface chemistry of the modified polymers. Plasma treatment and subsequent PEG grafting lead to dramatic changes in the polymer surface morphology, roughness and wettability. The plasma treated and PEG grafted polymers were seeded with rat vascular smooth muscle cells (VSMCs) and their adhesion and proliferation were studied. Biological tests, performed in vitro, show increased adhesion and proliferation of cells on modified polymers. Grafting with PEG increases cell proliferation, especially on PS. The cell proliferation was shown to be an increasing function of PEG molecular weight.     

聚乙二醇对淀粉原位熔融接枝聚乳酸的影响

研究了在聚乙二醇(PEG)存在下,淀粉与丙交酯的原位熔融接枝反应。较系统地考察了PEG的加入量及分子量的变化对淀粉一聚乳酸原位熔融接枝反应的影响。结果表明,当有PEG存在时,丙交酯可以有效地接枝到淀粉链上,得到淀粉一聚乳酸接枝共聚物。PEG对淀粉的增塑效果是影响淀粉与丙交酯熔融接枝反应至关重要的因素。