Synthesis and Characterization of Patterned Microvascular Networks

这项为期五年的提案将开发体外合成功能性微血管网络的方法。 这项工作的核心是：1）使用光刻来生成三维（3D）结构， 以人类微血管床的形状开放的内部拓扑结构，以及2）合成的 通过连续优化培养条件（剪切应力，内腔压力，氧化应激， 和基质蛋白水解活性）。为圆柱形微血管的成熟而定制的条件，其中 流动剖面很容易确定，将作为微加工通道成熟的起点 和具有非圆形横截面的网络。这项工作将提供培养条件， 两种特征性微血管功能（屏障功能和对细胞因子的反应性）的发展 并将确定这些功能在体外共存的程度。之间的时间相关性 这些行为和组织学变化的出现将建议进一步加强 成熟这项工作还将确定微血管网络如何重塑（即，他们的 横截面形状和网络拓扑随时间变化），并将建议3D设计原则 在连续灌注的情况下保持其初始拓扑结构的网络。一般来说，这 工作将说明光刻方法的组织工程的独特能力。 在短期内，这些网络将作为替代人类血管组织的高通量 筛选可能干扰或增强微血管功能的药物。从长远来看， 网络可以增强体外人工组织的灌注，从而克服其中一个主要问题， 组织工程的障碍。

This five-year proposal will develop methods to synthesize functional microvascular networks in vitro. Central to this work are: 1) the use of lithography to generate three-dimensional (3D) constructs that have open internal topologies in the shape of human microvascular beds, and 2) maturation of as-synthesized structures by sequential optimization of culture conditions (shear stress, lumenal pressure, oxidative stress, and matrix proteolytic activity). Conditions tailored for maturation of cylindrical microvessels, in which the flow profile is easily determined, will serve as a starting point for maturation of microfabricated channels and networks that have non-circular cross-sections. This work will provide culture conditions that enhance the development of two characteristic microvascular functions (barrier function and reactivity to cytokines) and will determine to what extent these functions may co-exist in vitro. Temporal correlation between the emergence of these behaviors and changes in histology will suggest strategies to further enhance maturation. This work will also determine how microvascular networks remodel (i.e., how their cross-sectional shapes and network topologies change over time), and will suggest design principles for 3D networks that preserve their initial topologies in the presence of continuous perfusion. More generally, this work will illustrate the unique capabilities of a lithographic approach to tissue engineering. In the short-term, these networks will serve as surrogate human vascular tissues for high-throughput screening of drugs that may perturb or enhance microvascular function. In the long-term, engineered networks may enhance the perfusion of artificial tissues in vitro, and thereby overcome one of the primary obstacles in tissue engineering.