High Density 3D Printed Microfluidics for Cell-Based Biomedical Applications

项目摘要 生长因子、其他细胞信号分子和营养物质的浓度梯度驱动了广泛的生长。 一系列关键的生物过程，包括免疫细胞迁移，血管生成，伤口愈合， 癌症转移和生物体发育。微流体装置被广泛用于创建 相关的浓度梯度，并监测响应于该梯度的细胞行为。 不幸的是，大多数浓度梯度微流体装置被设计为仅假设 扩散输送过程，同时结合平流输送解耦策略， 很大程度上无效和/或缓慢。这种方法导致具体和重要的缺点，包括低 梯度的动态范围，在测量寿命期间不稳定的梯度，以及 设备的不同空间区域之间的梯度不一致。因此，现有 浓度梯度构造的微流体方法不能充分模拟扩散， 产生体内发现的浓度梯度。因此，对于微流体技术存在很大的未满足的需求。 可以快速产生稳定和灵活的浓度梯度的设备， 监测关键的细胞过程。 此更新建议侧重于利用和扩展复杂的高分辨率3D 用于微流体的打印技术，以创建产生浓度梯度的集成设备 具有大动态范围，可在多个源和接收器解决方案之间切换， 可选择的浓度和快速的设置时间（几分钟），以实现时间复用， 稳定的浓度梯度序列。研究工作将包括三个具体目标。第一、 将采用3D模拟来评估大范围的浓度梯度形成 几何形状基于一个新的逆流概念的源和汇流体的目标， 平流与扩散物质输送解耦，需要前者补充源 并且下沉流体，而后者需要产生浓度梯度。接下来，各种 候选几何形状将被3D打印和测试，以迭代优化浓度梯度 动态范围、建立时间、稳定性和均匀性。最佳候选产品将与片上 泵、阀、系列稀释器和储液器，以创建集成系统。最后，这些设备将 用于分析代谢工程菌的趋化性。开发的新功能 赠款期限旨在回答以下重要问题： 发育生物学、细胞对营养信号的反应以及血管生成和癌症生长 和侵略性。

Project Summary Concentration gradients of growth factors, other cell-signaling molecules, and nutrients drive a wide range of critical biological processes, including immune cell migration, angiogenesis, wound healing, cancer metastasis, and organism development. Microfluidic devices are extensively used to both create the relevant concentration gradient, and to monitor cellular behavior in response to that gradient. Unfortunately, most concentration gradient microfluidic devices are designed assuming exclusively diffusional transport processes, while incorporating advective transport decoupling strategies that are largely ineffective and/or slow. This approach results in specific and important drawbacks, including low dynamic range in the gradient, unstable gradients over the lifetime of the measurement, and inconsistency in the gradient between different spatial regions of the device. As a result, existing microfluidic approaches to concentration gradient construction do not adequately mimic the diffusion- generated concentration gradients found in-vivo. Hence, there is a large unmet need for microfluidic devices that can rapidly create stable and flexible concentration gradients that allow sensitive monitoring of critical cellular processes. This renewal proposal focuses on leveraging and extending sophisticated high resolution 3D printing technology for microfluidics to create integrated devices that generate concentration gradients with large dynamic range that are switchable between multiple source and sink solutions with selectable concentration and rapid set up time (few minutes) to enable temporal multiplexing of sequences of stable concentration gradients. Research efforts will consist of three specific aims. First, 3D simulation will be employed to evaluate a wide range of concentration gradient formation geometries based on a new opposing-flow concept for source and sink fluids with the objective of decoupling advective from diffusive mass transport, where the former is needed to replenish source and sink fluids while the latter is required to generate the concentration gradient. Next, a variety of candidate geometries will be 3D printed and tested to iteratively optimize concentration gradient dynamic range, set up time, stability, and uniformity. The best candidates will be integrated with on-chip pumps, valves, serial diluters, and reservoirs to create integrated systems. Finally, such devices will be used to analyze chemotaxis of metabolically engineered bacteria. The new capabilities developed over the grant period are designed to allow important questions to be answered with respect to developmental biology, cellular response to nutritive cues, as well as angiogenesis, and cancer growth and invasiveness.