Multi-functional bilayer polymeric coatings are prepared with both controlled nitric oxide (NO) release and surface-bound active thrombomodulin (TM) alone or in combination with immobilized heparin. The outer-layer is made of CarboSil, a commercially available copolymer of silicone rubber (SR) and polyurethane (PU). The CarboSil is either carboxylated or aminated via an allophanate reaction with a diisocyanate compound followed by a urea-forming reaction between the generated isocyanate group of the polymer and the amine group of an amino acid (glycine), an oligopeptide (triglycine) or a diamine. The carboxylated CarboSil can then be used to immobilize TM through the formation of an amide bond between the surface carboxylic acid groups and the lysine residues of TM. Aminated CarboSil can also be employed to initially couple heparin to the surface, and then the carboxylic acid groups on heparin can be further used to anchor TM. Both surface-bound TM and heparin's activity are evaluated by chromogenic assays and found to be at clinically significant levels. The underlying NO release layer is made with another commercial SR-PU copolymer (PurSil) mixed with a lipophilic NO donor (N-diazeniumdiolated dibutylhexanediamine (DBHD/N(2)O(2))). The NO release rate can be tuned by changing the thickness of top coatings, and the duration of NO release at physiologically relevant levels can be as long as 2 weeks. The combination of controlled NO release as well as immobilized active TM and heparin from/on the same polymeric surface mimics the highly thromboresistant endothelium layer. Hence, such multifunctional polymer coatings should provide more blood-compatible surfaces for biomedical devices.

译文

:多功能双层聚合物涂料既可单独控制一氧化氮(NO)释放,又可与固定化肝素联合使用表面结合的活性血栓调节蛋白(TM)。外层由CarboSil制成,CarboSil是硅橡胶(SR)和聚氨酯(PU)的市售共聚物。 CarboSil通过与二异氰酸酯化合物的脲基甲酸酯反应被羧化或胺化,然后在聚合物的生成的异氰酸酯基团与氨基酸(甘氨酸),寡肽(三甘氨酸)或二胺的胺基之间形成脲形成反应。然后,可通过在表面羧酸基团与TM的赖氨酸残基之间形成酰胺键,将羧化的CarboSil固定在TM上。也可以使用胺化的CarboSil首先将肝素偶联至表面,然后可以进一步使用肝素上的羧酸基团来固定TM。表面结合的TM和肝素的活性均通过生色测定法进行评估,并发现在临床上具有显着水平。下层的NO释放层是由另一种商业SR-PU共聚物(PurSil)与亲油的NO供体(N-重氮二醇二丁基己二胺(DBHD / N(2)O(2)))混合制成的。可以通过改变表面涂层的厚度来调节NO的释放速率,并且在生理上相关的水平上,NO的释放持续时间可以长达2周。从同一聚合物表面上/上的受控NO释放以及固定化的活性TM和肝素的组合模拟了高度抗血栓形成的内皮层。因此,这种多功能聚合物涂层应为生物医学装置提供更多的血液相容性表面。

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