This study explores three unique approaches for closing valves and channels within microfluidic systems, specifically multilayer, centrifugally driven polymeric devices. Precise control over the cessation of liquid movement is achieved through either the introduction of expanding polyurethane foam, the application of direct contact heating, or the redeposition of xerographic toner via chloroform solvation and evaporation. Each of these techniques modifies the substrate of the microdevice in a different way. All three are effective at closing a previously open fluidic pathway after a desired unit operation has taken place, i.e., sample metering, chemical reaction, or analytical measurement. Closing previously open valves and channels imparts stringent fluidic control—preventing backflow, maintaining pressurized chambers within the microdevice, and facilitating sample fractionation without cross-contamination. As such, a variety of microfluidic bioanalytical systems would benefit from the integration of these valving approaches.

中文翻译：

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用于聚合物微流体装置的可关闭阀门和通道。


这项研究探索了三种独特的方法来关闭微流体系统中的阀门和通道，特别是多层、离心驱动的聚合物装置。通过引入膨胀聚氨酯泡沫、应用直接接触加热或通过氯仿溶剂化和蒸发重新沉积静电复印墨粉，可以实现对液体运动停止的精确控制。这些技术中的每一种都以不同的方式修改微型器件的基板。在发生所需的单元操作（即样品计量、化学反应或分析测量）之后，这三种方法都可以有效地关闭先前打开的流体路径。关闭先前打开的阀门和通道可实现严格的流体控制——防止回流、维持微型装置内的加压室，并促进样品分级而不会交叉污染。因此，各种微流体生物分析系统将受益于这些阀门方法的集成。