Meffan Claude, Menges Julian, Dolamore Fabian, Mak Daniel, Fee Conan, Dobson Renwick C J, Nock Volker
Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, 8041 New Zealand.
Department of Microengineering, Kyoto University, 615-8540 Kyoto, Japan.
Microsyst Nanoeng. 2022 Mar 21;8:33. doi: 10.1038/s41378-022-00360-8. eCollection 2022.
Controlling fluid flow in capillaric circuits is a key requirement to increase their uptake for assay applications. Capillary action off-valves provide such functionality by pushing an occluding bubble into the channel using a difference in capillary pressure. Previously, we utilized the binary switching mode of this structure to develop a powerful set of fundamental fluidic valving operations. In this work, we study the transistor-like qualities of the off-valve and provide evidence that these structures are in fact functionally complementary to electronic junction field effect transistors. In view of this, we propose the new term capillaric field effect transistor to describe these types of valves. To support this conclusion, we present a theoretical description, experimental characterization, and practical application of analog flow resistance control. In addition, we demonstrate that the valves can also be reopened. We show modulation of the flow resistance from fully open to pinch-off, determine the flow rate-trigger channel volume relationship and demonstrate that the latter can be modeled using Shockley's equation for electronic transistors. Finally, we provide a first example of how the valves can be opened and closed repeatedly.
控制毛细管回路中的流体流动是提高其在分析应用中摄取量的关键要求。毛细管作用截止阀通过利用毛细管压力差将一个阻塞气泡推入通道来提供这种功能。此前，我们利用这种结构的二元切换模式开发了一套强大的基本流体阀操作。在这项工作中，我们研究了截止阀的类似晶体管的特性，并提供证据表明这些结构实际上在功能上与电子结型场效应晶体管互补。鉴于此，我们提出了新术语“毛细管场效应晶体管”来描述这些类型的阀。为支持这一结论，我们给出了模拟流阻控制的理论描述、实验表征和实际应用。此外，我们证明了这些阀也可以重新打开。我们展示了从完全打开到夹断的流阻调制，确定了流速触发通道体积关系，并证明后者可以使用电子晶体管的肖克利方程进行建模。最后，我们提供了阀如何反复打开和关闭的第一个示例。
