Department of Chemical and Biomolecular Engineering, University of Nebraska, Lincoln, 207 Othmer Hall, Lincoln, NE 68588-0643, USA.
J Biomater Sci Polym Ed. 2011;22(15):1983-99. doi: 10.1163/092050610X529191. Epub 2010 Nov 2.
Surface modifications of polyurethane (PU)-based implantable materials have the potential to enhance or improve hemo- or cellular-biocompatibility. In general, surface modification methods of PU have included surface treatments, physio-adsorption of desired biomolecules, and the covalent immobilization of reactive or therapeutic biomolecules. When multi-protein immobilizations are desired to mimic the enzymatic reactions found on cells and tissues, it is often necessary to design and develop surface modification strategies that will allow the co-immobilization of proteins. In this study, a surface modification strategy is presented that enables the sequential additional of proteins to a bi-dentate moiety grafted onto the PU surface. The modifications were confirmed via IR and XPS signatures. While the strategy presented is applicable to a wide variety of biomolecules, bovine serum albumin (BSA) and human immunoglobulin (hIgG) were selected as model proteins. A total immobilized protein density of 0.298 ± 0.037 μg/cm² was obtained, with nearly equal amounts of protein on each arm of the bi-dentate moiety. Proteins immobilizations were also visualized with immunofluorescent staining. Finally, the method proposed in this study was used to demonstrate a significant increase (P < 0.05) in the catalytic conversion of protein C (PC) to activated PC (APC) using sequentially immobilized thrombomodulin (TM) and endothelial PC receptor (EPCR) as compared to the two proteins immobilized onto a surface in random order.
基于聚氨酯（PU）的可植入材料的表面修饰具有增强或改善血液或细胞生物相容性的潜力。一般来说，PU 的表面修饰方法包括表面处理、所需生物分子的物理吸附以及反应性或治疗性生物分子的共价固定。当需要模拟细胞和组织中存在的酶反应来进行多蛋白固定时，通常需要设计和开发允许蛋白质共固定的表面修饰策略。在这项研究中，提出了一种表面修饰策略，使蛋白质能够顺序添加到接枝到 PU 表面的双齿部分上。通过 IR 和 XPS 特征证实了修饰。虽然提出的策略适用于多种生物分子，但选择牛血清白蛋白（BSA）和人免疫球蛋白（hIgG）作为模型蛋白。获得了 0.298 ± 0.037 μg/cm²的总固定蛋白密度，双齿部分的每个臂上的蛋白量几乎相等。还通过免疫荧光染色观察了蛋白质固定。最后，使用该方法证明了与随机顺序固定到表面上的两种蛋白质相比，通过顺序固定血栓调节蛋白（TM）和内皮蛋白 C 受体（EPCR），固定在表面上的蛋白质 C（PC）到激活的 PC（APC）的催化转化率显著增加（P < 0.05）。
