Development of a biomimetic composite scaffold to promote vascular network growth

描述(由申请人提供)：新型仿生支架的开发能够促进和引导新的血管网络生长，是组织工程成功和快速解决慢性伤口愈合的关键障碍。传统上，仿生支架只与细胞外基质(ECM)纤维直径匹配，但我们的初步结果表明，模拟血管ECM的机械、化学和地形特性的支架比传统支架更快地促进新血管网络的生长。这个项目的长期目标是非常成功地制造出促进血管网络生长的仿生支架。该方案的目的是制备新型复合仿生同轴电纺支架，并在体外、体外和体内血管生成模型中测试这些支架促进新生血管生长的倾向。在这里，我们的基础支架将是我们已建立的部分模拟电纺支架，我们将定制剩余的物理属性，以匹配ECM。这一建议的中心假设是，与不模拟血管ECM特性的支架相比，模拟血管ECM多种物理属性的电纺支架将更好地支持新血管的生长。我们的基本原理是，通过设计一种促进功能性血管网络生长的支架，血管组织可以被整合到组织工程产品中，或者可以用于促进伤口愈合。这两种应用的成功，都将极大地改变血管组织工程、组织工程和伤口愈合领域。这一建议与美国国立卫生研究院的使命特别相关，该使命涉及寻求关于系统行为的基本知识，并应用这些知识来延长健康的生命。在我们的初步数据的指导下，这一建议的假设将通过追求三个具体目标来验证：1)构建血管ECM模拟支架，2)研究体外和体外新生血管网络在整个ECM模拟支架中的生长，以及3)利用小鼠伤口愈合模型检测整个ECM模拟支架中的体内血管生成。电纺丝将被用于制备复合仿生同轴支架。支架的物理性能将通过纳米压痕、透射电子显微镜、扫描电子显微镜和测角法进行研究。针对E-选择素、VE-钙粘附素、ICAM等的内皮细胞激活将在细胞培养、生物测定室中和小鼠模型中用流式细胞仪和ELISA进行研究，以监测来自自体细胞来源的新血管生成。这项拟议的工作具有创新性，因为我们开发了一种新的同轴静电纺丝技术，该技术是为提高成型支架的机械性能而量身定做的。此外，我们使用了由该小组开发的促血管生成生物测定室。这项研究将对组织工程/创伤愈合研究产生积极影响，并具有重要意义，因为我们将开发一种技术，在生物兼容的仿生支架内构建新的血管网络。我们已经组建了一支研究团队，他们拥有成功解决这一重要问题的专业知识和动力。 公共卫生相关性：该项目对组织工程领域的成功非常重要，因为在该项目成功完成后，我们将开发出一种在复杂的复合生物兼容仿生支架中快速构建血管网络的方法。这项拟议的研究与公共健康相关，因为我们将获得组织工程多种产品的能力，这些产品具有整合的血管网络，并促进慢性伤口愈合。

DESCRIPTION (provided by applicant): The development of novel biomimetic scaffolds that promote and direct new vascular network growth is a critical hurdle for the success of tissue engineering and for a rapid solution for chronic wound healing. Traditionally, biomimetic scaffolds only match the extracellular matrix (ECM) fiber diameter, but our preliminary results suggest that scaffolds that mimic the mechanical, chemical and topographical properties of the vascular ECM promote new vascular network growth faster than traditional scaffolds. The long-term goal of this project is too successful fabricate biomimetic scaffolds that promote vascular network growth. The objective of this proposal is to fabricate novel composite biomimetic coaxial electrospun scaffolds and to test the propensity of these scaffolds to promote new vascular growth in an in vitro, ex vivo and in vivo angiogenesis model. Here our base scaffolds will be our established partially mimetic electrospun scaffolds and we will tailor the remaining physical properties to match the ECM. The central hypothesis of this proposal is that electrospun scaffolds that mimic multiple physical properties of the vascular ECM will support new vessel growth better than scaffolds that do not mimic the vascular ECM properties. Our rationale is that by designing a scaffold that facilitates functional vascular network growth, vascular tissue can be incorporated into tissue engineered products or can be used to facilitate wound healing. The success of either of these applications, would significantly transform the fields of vascular tissue engineering, tissue engineering and wound healing. This proposal is especially relevant to the NIH's mission that pertains to the pursuit of fundamental knowledge about the behavior of systems and the application of that knowledge to extend healthy life. Guided by our preliminary data, the hypothesis of this proposal will be tested by pursing three specific aims: 1) To fabricate vascular ECM mimicking scaffolds, 2) To investigate the in vitro and ex vivo new vascular network growth throughout ECM mimicking scaffolds, and 3) To examine in vivo angiogenesis throughout ECM mimicking scaffolds using a murine wound healing model. Electrospinning will be used to fabricate complex composite biomimetic coaxial scaffolds. Scaffold physical properties will be investigated with nanoindentation, TEM, SEM and goniometry. Endothelial cell activation will be investigated with flow cytometry and ELISA directed towards E-selectin, VE-cadherin, ICAM, etc., in cell culture, in a bioassay chamber optimized to monitor new angiogenesis from an autologous cell source and in a murine model. The proposed work is innovative because we have developed a new coaxial electrospinning technique that is tailored to enhance the mechanical properties of formed scaffolds. Also, we use a pro-angiogenic bioassay chamber that was developed by this group. This research will have a positive impact on tissue engineering/wound healing research and is significant because we will develop a technique to fabricate new vascular networks within a biocompatible biomimetic scaffold. We have put together a research team that has the expertise and drive to successfully address this important question. PUBLIC HEALTH RELEVANCE: The proposed project is important to the success of the tissue engineering field because after the successful completion of this project we will have developed a method to rapidly fabricate vascular networks within complex composite biocompatible biomimetic scaffolds. The proposed research has relevance to public health because we will gain the ability to tissue engineer multiple products with incorporated vascular networks and facilitate chronic wound healing.