Reactive Ion Plasma Treatment of Cardiovascular Biomaterials to Understand the Effect of Nanotopography on Endothelialization

项目摘要 该项目提出通过将表面形貌与内皮化分离来研究表面形貌在内皮化中的作用。 使用外周血管移植物（PVG）生物材料的反应离子等离子体（RIP）的表面化学，包括 有前途的材料：聚乙烯醇（PVA）。超过一半由合成材料制成的PVG在两个小时内失效 多年的植入和治疗，以减少因素造成的移植失败已显示没有好处， 下肢PVG结局。由于PVG的两种主要失效模式是血栓形成（血液 凝血）和内膜增生（移植物内的组织积聚），理想的PVG生物材料应具有耐受性 都是这种材料的主要属性是：1）具有与天然材料相当的顺应性， 血管，2）不形成血栓，和3）促进内皮化。RIP处理的PVA是一种很有前途的 PVG材料，我们之前已经表明1）易于制造，符合范围从 静脉至动脉血管系统，2）血栓形成性低于当前临床标准PVG材料，以及3） 允许内皮祖细胞（EPCs）在体外在表面上增殖至少48小时。进展 制造可内皮化的PVG受到阻碍，因为这些方法主要涉及 将小分子结合到PVG材料上，这具有与成本，稳定性， 可重复性和可扩展性，尽管受到了极大的关注，但尚未转化为临床。 我们的项目集中在使用RIP处理，一种常见的可扩展的PVA制造工艺， 分离已知在内皮化过程中重要的两种表面性质：表面化学 和地形，以了解促进内皮化的基本因素， 我们的长期目标是生产更好的PVG。我们已经表明，RIP治疗引入了 以表面氮的形式存在的细胞粘附所必需的反应性表面化学，以及纳米纹理 PVA和不同程度的RIP处理。虽然大多数反应性表面化学 在储存230天后，RIP引入的表面仍然很明显，表面变得光滑，EPC不再 储存后粘附或增殖。我们将首先描述表面化学和地形的变化 在储存过程中，以了解材料表面的性质，因为地形松弛（目标1）。我们 然后将解耦表面化学和形貌对内皮细胞（EC）和EPC的影响 附着、增殖和迁移（Aim 2）以及EC和EPC功能， 流体流动（目标3）。这种理解将使我们能够确定表面化学和地形的影响 研究内皮化的重要过程并设计一种快速内皮化的PVG，该PVG仍然存在 专利时间长于目前的临床材料。我们的研究将提供一个更详细的了解的因素 其控制合成生物材料的内皮化，提供了解EC生物学的平台， PVG的改进的翻译，其可以应用于其它生物材料以改进它们的生物整合。

Project Summary This project proposes to investigate the role of surface topography in endothelialization by decoupling it from surface chemistry using reactive ion plasma (RIP) of peripheral vascular graft (PVG) biomaterials, including a promising material: polyvinyl alcohol (PVA). Over half of PVGs made from synthetic materials fail within two years of implantation and therapies to reduce the factors contributing to graft failure have shown no benefit in lower extremity PVG outcomes. Because the two predominant failure modes of PVGs are thrombosis (blood clotting) and intimal hyperplasia (tissue build-up inside the graft), an ideal PVG biomaterial should be resistant to both. The primary attributes of such a material are that it 1) have comparable compliance to the native vasculature, 2) be non-thrombogenic, and 3) encourage endothelialization. RIP-treated PVA is a promising PVG material which we have shown previously 1) is easily manufactured with compliance ranging from that of venous to arterial vasculature, 2) is less thrombogenic than the current clinical standard PVG material, and 3) allows endothelial progenitor cells (EPCs) to proliferate on the surface for at least 48 hours in vitro. Progress in manufacturing endothelializable PVGs has been hampered because the approaches predominantly involve conjugation of small molecules onto the PVG material, which have limitations associated with cost, stability, reproducibility, and scalability and despite significant attention have yet to be translated into the clinic. Our project is focused on using RIP treatment, a common and scalable manufacturing process, of PVA to decouple the two surface properties known to be important in the endothelialization process: surface chemistry and topography, in order to understand the fundamental factors that promote endothelialization and to achieve our long-term goal of manufacturing an improved PVG. We have shown that RIP-treatment introduces reactive surface chemistry necessary for cell adhesion in the form of surface nitrogen, as well as nanotexture to PVA and to varying degrees for different RIP treatments. While most of the reactive surface chemistry introduced by RIP is still apparent after 230 days in storage, the surface becomes smooth and EPCs no longer adhere or proliferate after storage. We will first characterize the changes in surface chemistry and topography during storage in order to understand the nature of the material surface as the topography relaxes (Aim 1). We will then decouple the effects of surface chemistry and topography on endothelial cell (EC) and EPC attachment, proliferation, and migration (Aim 2) as well as EC and EPC function with and without exposure to fluid flow (Aim 3). This understanding will allow us to determine the effect of surface chemistry and topography on the important processes of endothelialization and engineer a rapidly endothelializable PVG which remains patent longer than current clinical materials. Our studies will afford a more detailed understanding of the factors which govern endothelialization of synthetic biomaterials, provide a platform to understand EC biology, and improve translation of PVGs which can be applied to other biomaterials to improve their biointegration.