Microfluidic Tissue Engineering of Small Airway Injuries

在涉及小气道粘液分泌和运动的疾病中，如慢性支气管炎， 囊性纤维化或哮喘，液体堵塞形成阻塞的桥梁，阻塞呼吸道并扰乱气体。 交换。作为对咳嗽的反应，这些桥梁移动，呼吸道重新开放，伴随着 对呼吸道上皮细胞的机械力。同样，在同时涉及呼吸道和肺泡的环境中 空间，如肺炎或充血性心力衰竭，或低潮气量的机械通风 是周期性关闭和重新开放较小的呼吸道，这可能是容易听到的爆裂声 用听诊器。由它们产生的爆炸性瞬变压力波的细胞水平效应 然而，重新开放的事件以前没有被调查过，尽管相关的 塞子破裂会产生很大的压力，是肺损伤的主要原因。这项提案将进行调查， 从实验和理论上讲，流体机械应力对呼吸道上皮细胞的有害影响 在使用微工程气道重新开放期间。具体的假设是，运动和 在气道重新开放期间，小气道系统中液体塞的破裂将产生大量液体。 机械压力和损伤呼吸道上皮细胞，甚至正常情况下亚致死量的液体 机械压力在细菌或高氧等其他伤害的情况下会变得致命。 炎症，扩大损伤的区域和严重程度。这项建议的具体目标是： 1.用于呼吸道上皮细胞体外培养的仿生微流控系统的设计与制作 生理气液界面条件下的细胞。 2.产生具有生理传播速度和破裂频率的液塞 设计的微流控小气道，并结合计算和实验评估 由此产生的流体机械应力及其对细胞损伤的影响。 3.研究液体塞传播/破裂组合造成的协同细胞损伤- 介导的流体机械应力和细菌感染或高氧介导的炎症。另外， 评估表面活性物质作为减少细胞损伤的对策的效果。

In diseases that involve mucus secretion and movement in the small airways, such as chronic bronchitis, cystic fibrosis or asthma, liquid plugs form occluding bridges that obstruct the airway and disrupt gas exchange. In response to cough, these bridges move and the airway is reopened, with the transmission of mechanical forces to airway epithelial cells. Similarly, in the setting that involve both the airway and alveolar space, such as pneumonia or congestive heart failure, or mechanical ventilation with low tidal volumes, there is cyclic closure and reopening of smaller airways, which may be recognized as crackle sounds heard easily with a stethoscope. The cellular-level effect of the explosive transient pressure waves created by these reopening events, however, has not previously been investigated despite the likelihood that the associated plug rupture produces large stresses and is a major cause of lung injury. This proposal will investigate, experimentally and theoretically, the detrimental effect of fluid mechanical stresses on airway epithelial cells during airway reopening using a micro-engineered airway. The specific hypothesis is that the movement and rupture of liquid plugs in the small airway system during airway reopening will generate large fluid mechanical stresses and damage airway epithelial cells, and that even normally sub-lethal amounts of fluid mechanical stress will become lethal in the presence of other insults such as bacteria or hyperoxia-mediated inflammation, expanding the region and severity of injury. The specific aims of this proposal are: 1. Design and fabrication of a biomimetic microfluidic system to perform in vitro culture of airway epithelial cells under physiological air-liquid interface conditions. 2. Generation of liquid plugs with physiological propagation velocities and rupture frequencies within the engineered microfluidic small airways, and combined computational and experimental assessment of the resulting fluid mechanical stresses and their effect on cell injury. 3. Investigate synergistic cellular damage caused by combination of liquid plug propagation/rupture- mediated fluid mechanical stresses and bacterial infection or hyperoxia-mediated inflammation. Also, evaluate the effect of surfactant as a countermeasure to reduce cellular injuries.