OVERALL HEMOCOMPATIBILITY PEO-FUNCTIONALIZED SILOXANES

血液-聚合物界面的血栓形成混淆了生物材料的设计。 这项提案调查了一个令人兴奋的家庭的生物相容性。 在生物材料中，末端官能化的聚二甲基硅氧烷 聚(环氧乙烷)(PEO硅氧烷)，以进一步进行这种设计。这个 PEO硅氧烷的性能将被定制以优化血液 兼容性。其中包括聚乙烯的相对分子质量 氧化物)、其束缚密度和PEO的表面能级 底物。血小板行为和RGD蛋白吸附解释了 这些生物材料的血液相容性，将进行检查。巨噬细胞 PEO硅氧烷的粘附性和活化性也将在 以评估他们作为长期植入者的行为。我们会 研究玻璃连蛋白在这些生物材料上的吸附作用 因为它应该进一步表征它们的生物相容性。被吸附的 Vitronectin是黏附血液蛋白中独一无二的，因为血小板 玻璃连蛋白预吸附生物材料的沉积分布类似于 对于急性血栓形成的裸露对应者。的接触角 裸露和蛋白质预吸附的生物医学聚合物将被测量到 希望对PEO硅氧烷的抵抗能力提供洞察 蛋白质吸附。另一种RGD蛋白，纤维蛋白原的吸附， 将进行类似于维他林的研究，因为不同 由于不同的纤维蛋白原，预计纤维蛋白原会有吸附趋势 大小、血浆浓度等。孵化时间和孵化体积 将选择吸附浓度以最大限度地提高生物 吸附蛋白质的活性。 纤维蛋白原和玻璃体凝集素将从柠檬化的人血中分离出来 血浆。人血清白蛋白将作为对照。蛋白 吸附将被量化，动力学将被确定使用 放射性碘化蛋白质。放射性碘标记将使用 氯胺-T法。将使用计算机化的测角仪测量 裸露和蛋白质预吸附的聚氧乙烯硅氧烷的接触角 以确定这些表面的自由能。用于粘合 和吸附实验，将聚氧化硅氧烷旋转浇注到 用三氯硅烷处理过的清洁玻璃封套 让盖子变得疏水。 血小板将以活跃的形式被分离出来，并悬浮在Tyrodes的 人富含血小板凝胶过滤层析液的研究 血浆。将对凝胶过滤后的血小板的粘附性进行评估， 放射性标记它们在体外对裸鼠和裸鼠的粘附 蛋白质预吸附聚合物。将使用扫描电子显微镜 以评估血小板的循环性、扩散面积，从而评估其活化程度。 聚氧化硅氧烷也将用化学发光进行表征。 用光敏素评价细胞内活性氧的释放 巨噬细胞与这些生物材料接触。人类单核细胞- 衍生的巨噬细胞将通过淘洗获得。巨噬细胞将 也可以与PEO硅氧烷表面孵育，裸露或蛋白质- 用扫描电子显微镜预吸附、固定和成像 对其形态和粘附性进行评价。

Thrombosis at the blood-polymer interface confounds biomaterials design. This proposal investigates the biocompatibility of an exciting family of biomaterials, polydimethylsiloxanes end-functionalized with poly(ethylene oxide) (PEO siloxanes), to further such design. The properties of the PEO siloxanes will be tailored to optimize blood compatibility. These include the molecular weight of the poly(ethylene oxide), its tethering density, and the surface energetics of the PEO substrate. Platelet behavior and RGD protein adsorption elucidate the hemocompatibility of these biomaterials and will be examined. Macrophage adhesion and activation on the PEO siloxanes will also be examined in order to appraise their behavior as long-term implants. We will investigate the role of vitronectin adsorbed to these biomaterials because it should further characterize their biocompatibility. Adsorbed vitronectin is unique among adhesive blood proteins since the platelet deposition profiles to vitronectin-preadsorbed biomaterials resemble those to bare counterparts in acute thrombosis. The contact angle of bare and protein-preadsorbed biomedical polymers will be measured to hopefully provide insight into the ability of PEO siloxanes to resist protein adsorption. The adsorption of another RGD protein, fibrinogen, will be studied analogous to that of vitronectin because different adsorption tendencies are expected from fibrinogen due to different size, plasma concentration, and so forth. The incubation time and bulk concentration for adsorption will be selected to maximize the biological activity of adsorbed proteins. Fibrinogen and vitronectin will be isolated from citrated human blood plasma. Human serum albumin will be used as a control. Protein adsorption will be quantified and the kinetics determined using radioiodinated proteins. Radioiodination will be conducted using the chloramine-T method. A computerized goniometer will be used to measure the contact angles of bare and protein-preadsorbed PEO siloxanes in order to determine the free energies of these surfaces. For adhesion and adsorption experiments, the PEO siloxanes will be spin cast onto clean glass coverslips that have been pretreated with trichlorosilane to make the coverslips hydrophobic. Platelets will be isolated in an active form and suspended in Tyrodes' solution using gel-filtration chromatography of human platelet-rich plasma. The adhesion of gel-filtered platelets will be appraised, radiolabelling them for quantification of adhesion in vitro to bare and protein-preadsorbed polymers. Scanning electron microscopy will be used to assess platelet circularity, spread area and thus, activation. The PEO siloxanes will also be characterized with chemiluminescence using lucigenin to appraise the release of reactive oxygen species by macrophages in contact with these biomaterials. The human monocyte- derived macrophages will be obtained by elutriation. Macrophages will also be incubated with surfaces of the PEO siloxanes, bare or protein- preadsorbed, fixed, and imaged with scanning electron microscopy to appraise morphology and adhesion.