Lim F, Yu X H, Cooper S L
Department of Chemical Engineering, University of Wisconsin, Madison 53706.
Biomaterials. 1993 Jun;14(7):537-45. doi: 10.1016/0142-9612(93)90243-u.
A series of oligoethylene oxide monoalkyl(aryl) alcohol ethers was grafted on to the backbone of a polytetramethylene oxide (PTMO)-based polyurethane, in an attempt to improve its biocompatibility. Each polyurethane contained a different pendant chain grafted to the urethane nitrogen atoms. The grafted chains consisted of various short lengths of hydrophillic oligomeric poly(ethylene oxide) (PEO) spacer segments and alkyl/aryl hydrophobic terminal groups. By using the 1H-NMR (nuclear magnetic resonance) technique, the extent of grafting was found to range from 7 to 12 mol% substitution of the urethane hydrogen groups. The surface properties of these materials were evaluated using high-vacuum, air-equilibrated and water-equilibrated methods. X-ray photoelectron spectroscopy (XPS) and static and dynamic contact angle experiments were performed. XPS showed that all of the grafted polyurethane surfaces contained higher ratios of C1s to O1s than the base polyurethane. These C:O contents correlate with the C:O ratios of the grafted chains. Dynamic contact angle analysis showed larger contact angle hysteresis for the grafted polyurethanes. The grafted polyurethanes generally exhibit lower complement activation, measured by an in vitro assay for C3a. A canine ex vivo arteriovenous series shunt was used to monitor platelet and fibrinogen deposition on these polymers. The incorporation of short ethylene oxide spacer segments with terminal C18 linear alkyl chains resulted in an improved short-term (up to 15 min) blood compatibility compared to the underivatized polyurethane. At longer blood contact times, all the grafted polyurethanes were more thrombogenic than the base polyurethane. In addition, there was no observable correlation between the material surface properties and the blood contact response.
一系列低聚环氧乙烷单烷基（芳基）醇醚被接枝到聚四亚甲基醚二醇（PTMO）基聚氨酯的主链上，以试图改善其生物相容性。每种聚氨酯都含有接枝到氨基甲酸酯氮原子上的不同侧链。接枝链由各种不同长度的亲水性低聚聚环氧乙烷（PEO）间隔段和烷基/芳基疏水端基组成。通过使用1H-核磁共振（NMR）技术，发现接枝程度在氨基甲酸酯氢基团取代量的7%至12摩尔%范围内。使用高真空、空气平衡和水平衡方法评估了这些材料的表面性质。进行了X射线光电子能谱（XPS）以及静态和动态接触角实验。XPS表明，所有接枝聚氨酯表面的C1s与O1s之比均高于基础聚氨酯。这些C:O含量与接枝链的C:O比率相关。动态接触角分析表明，接枝聚氨酯的接触角滞后较大。通过C3a的体外测定法测得，接枝聚氨酯通常表现出较低的补体激活。使用犬类体外动静脉串联分流装置监测血小板和纤维蛋白原在这些聚合物上的沉积。与未衍生化的聚氨酯相比，含有末端C18直链烷基链的短环氧乙烷间隔段的引入改善了短期（长达15分钟）血液相容性。在更长的血液接触时间下，所有接枝聚氨酯比基础聚氨酯更具血栓形成性。此外，材料表面性质与血液接触反应之间没有可观察到的相关性。
