Rational Design of Bioactive Materials via Substrate Composition and Compliance

描述(申请人提供)：这项探索性研究将拓宽生物材料科学所基于的现有范式，证明细胞生物学文献可以用来指导生物材料表面修饰的发展，从而引发所需的细胞行为。在这项研究中，我们的目的是确定在调控内皮细胞对炎症细胞的募集中起重要作用的主要因素。我们假设这些因素包括与细胞结合的细胞外基质(ECM)蛋白的组成，ECM底物的机械性能，以及流体流动对细胞施加的剪应力。在正常生理条件下，内皮细胞表面产生高水平的一氧化氮(NO)和低数量的细胞内黏附分子1(ICAM-1)和E-选择素分子。ICAM-1和E-选择素是炎症反应的重要分子，因为中性粒细胞上的相应分子可以通过它们与血管内皮细胞结合，而低浓度的NO会导致其中之一的上调。减少炎症是生物材料科学的一个重要目标，因为设备失效的两个最常见的原因是急性炎症和慢性瘢痕形成。我们的第一个目标将通过比较内皮细胞在基质、层粘连蛋白-1、IV型胶原、III型胶原、I型胶原和纤维连接蛋白表面黏附的NO、ICAM-1和E-选择素的水平来实现，这些表面是通过吸附或凝胶产生的。实验将在流动和静态条件下进行。在第二个目标中，我们将在流动和静态条件下测量白细胞与培养在相同底物上的内皮细胞的粘附性。这项研究具有直接适用性的应用是血管移植物和动静脉分流术，它们通常由于植入物边缘的血管壁增厚而失去通畅性，从而堵塞血管管腔并减少血流量。最终，我们将使用这里开发的模型系统来研究生物材料的体外结果和体内疗效之间通常缺乏相关性的问题。在这里，我们使用一种最初为活体显微镜开发的实验技术，这将使我们能够在体内使用相同的实验测量技术，从而极大地促进此类研究。

DESCRIPTION (provided by applicant): This exploratory study will broaden the existing paradigm on which biomaterials science is based by demonstrating that the cell biology literature can be used to guide development of biomaterial surface modifications that can elicit desired cell behaviors. In this study we aim to identify the main factors important in regulation of endothelial cell recruitment of inflammatory cells. We hypothesize that these factors include the composition of the extracellular matrix (ECM) proteins to which the cells bind, the mechanical properties of the ECM substrate, and the shear stress imparted on the cells by fluid flow. In normal physiology, endothelial cells produce high levels of nitric oxide (NO) and low numbers of Intracellular Adhesion Molecule 1 (ICAM-1) and E-selectin molecules on their surfaces. ICAM-1, and E-selectin are important molecules in the initiation of inflammation because correponding molecules on neutrophils can bind to the endothelial lining of blood vessels through them, and low concentrations of NO lead to up-regulation of one of these. Reduction of inflammation is an important goal of biomaterials science as two of the most prevalent reasons for device failure are acute inflammation and chronic scarring. Our first aim will be accomplished by comparing the levels of NO, ICAM-1, and E-selectin produced by endothelial cells adhered to Matrigel, laminin-1, collagen IV, collagen III, collagen I, and fibronectin surfaces which have been created either by adsoption or gelation. Experiments will be performed under flow and static conditions. In the second aim, we will measure leukocyte adhesion to endothelial cells cultured on the same substrates also under flow and static conditions. The applications to which this study has direct applicability are vascular grafts and arteriovenous shunts which often lose patency by vascular wall thickening at the edges of the implant that occludes the vessel lumen and decreases blood flow. Eventually we will use the model system developed here to study the usual lack of correlation between in vitro results and in vivo efficacy of biomaterials. Here we use an experimental technique originally developed for intravital microscopy, and this will greatly facilitate such studies by allowing us to use identical experimental measurement techniques in vivo.