For highly-integrated microfluidic systems, an actuation system is necessary to control the flow; however, the bulk of actuation devices including pumps or valves has impeded the broad application of integrated microfluidic systems. Here, we suggest a microfluidic process control method based on built-in microfluidic circuits. The circuit is composed of a fluidic timer circuit and a pneumatic logic circuit. The fluidic timer circuit is a serial connection of modularized timer units, which sequentially pass high pressure to the pneumatic logic circuit. The pneumatic logic circuit is a NOR gate array designed to control the liquid-controlling process. By using the timer circuit as a built-in signal generator, multi-step processes could be done totally inside the microchip without any external controller. The timer circuit uses only two valves per unit, and the number of process steps can be extended without limitation by adding timer units. As a demonstration, an automation chip has been designed for a six-step droplet treatment, which entails 1) loading, 2) separation, 3) reagent injection, 4) incubation, 5) clearing and 6) unloading. Each process was successfully performed for a pre-defined step-time without any external control device.

中文翻译：

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使用模块化定时器电路的多步骤片上实验室过程的完全嵌入式芯片自动化

对于高度集成的微流体系统，必须有一个致动系统来控制流量。然而，包括泵或阀在内的大量致动装置阻碍了集成微流体系统的广泛应用。在这里，我们建议基于内置微流控电路的微流控方法。该电路由流体计时器电路和气动逻辑电路组成。流体定时器电路是模块化定时器单元的串行连接，该定时器单元依次将高压传递到气动逻辑电路。气动逻辑电路是一个NOR门阵列，用于控制液体控制过程。通过使用定时器电路作为内置信号发生器，可以完全在微芯片内部完成多步处理，而无需任何外部控制器。计时器电路每个单元仅使用两个阀，并且通过添加计时器单元可以不受限制地扩展处理步骤的数量。作为演示，已设计了用于六步液滴处理的自动化芯片，该过程需要1）加载，2）分离，3）试剂注入，4）孵育，5）清除和6）卸载。在没有任何外部控制设备的情况下，每个过程都已成功执行了预定的步骤。