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 生物材料，聚二甲基硅氧烷末端官能化， 聚（环氧乙烷）（PEO硅氧烷），以进一步这种设计。 的 PEO硅氧烷的特性将被定制，以优化血液 兼容性. 这些包括聚（乙烯）的分子量 氧化物）、其束缚密度和PEO的表面能 衬底血小板行为和RGD蛋白吸附阐明了 这些生物材料的血液相容性，并将进行检查。巨噬 在PEO硅氧烷上的粘附和活化也将在 来评估它们作为长期植入物的行为。 我们将 研究玻连蛋白吸附到这些生物材料上的作用 因为它应该进一步表征它们的生物相容性。 吸附 玻连蛋白在粘附性血液蛋白中是独特的，因为血小板 玻连蛋白预吸附生物材料的沉积曲线类似于 与急性血栓形成中的裸对应物相比。 的接触角 将测量裸的和蛋白质预吸附的生物医学聚合物， 希望提供对PEO硅氧烷抵抗 蛋白质吸附 另一种RGD蛋白，纤维蛋白原， 将类似于玻连蛋白进行研究，因为不同的 由于纤维蛋白原的不同， 大小、血浆浓度等等。孵育时间和体积 将选择用于吸附的浓度以最大化生物活性。 吸附蛋白的活性。 将从柠檬酸化人血中分离纤维蛋白原和玻连蛋白 等离子体 人血清白蛋白将用作对照。蛋白 将对吸附进行定量，并使用 放射性碘标记蛋白质。 放射性碘化将使用 氯胺T法 将使用计算机化的测角仪测量 裸露的和蛋白质预吸附的PEO硅氧烷的接触角， 以确定这些表面的自由能。 用于粘附 和吸附实验，将PEO硅氧烷旋涂到 用三氯硅烷预处理的干净盖玻片 以使盖玻片疏水。 血小板将以活跃的形式被隔离，并悬浮在Tyrodes的 使用凝胶过滤色谱法对富含人血小板的溶液 等离子体 将评价凝胶过滤血小板的粘附性， 放射性标记它们以定量体外粘附至裸细胞， 蛋白质预吸附聚合物。采用扫描电子显微镜 以评估血小板的圆形度、扩散面积以及活化。 PEO硅氧烷也将用化学发光进行表征 用光泽精评价活性氧的释放， 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析获得。 Macrology将 也可以与PEO硅氧烷的表面，裸露的或蛋白质- 预吸附、固定并用扫描电子显微镜成像， 评价形态和附着力。

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.