Institute of Nano Science and Technology, Hanyang University, Seoul, Korea04763.
Analyst. 2021 Mar 21;146(6):1932-1939. doi: 10.1039/d0an02279a. Epub 2021 Jan 25.
Capillary-driven microfluidic devices are of significant interest for on-site analysis because they do not require external pumps and can be made from inexpensive materials. Among capillary-driven devices, those made from paper and polyester film are among the most common and have been used in a wide array of applications. However, since capillary forces are the only driving force, flow is difficult to control, and passive flow control methods such as changing the geometry must be used to accomplish various analytical applications. This study presents several new flow control methods that can be utilized in a laminate capillary-driven microfluidic device to increase available functionality. First, we introduce push and burst valve systems that can stop and start flow. These valves can stop flow for >30 min and be opened by either pressing the channel or inflowing other fluids to the valve region. Next, we propose flow control methods for Y-shaped channels that enable more functions. In one example, we demonstrate the ability to accurately control concentration to create laminar, gradient, and fully mixed flows. In a second example, flow velocity in the main channel is controlled by adjusting the length of the inlet channel. In addition, the flow velocity is constant as the inlet length increases. Finally, the flow velocity in the Y-shaped device as a function of channel height and fluid properties such as viscosity and surface tension was examined. As in previous studies on capillary-driven channels, the flow rate was affected by each parameter. The fluidic control tools presented here will enable new designs and functions for low cost point of need assays across a variety of fields.
基于毛细作用力的微流控装置因其无需外部泵且可由廉价材料制成而备受现场分析的关注。在基于毛细作用力的装置中，纸基和聚酯薄膜基装置最为常见，已被广泛应用于各种领域。然而，由于毛细作用力是唯一的驱动力，因此难以控制流动，必须采用改变几何形状等被动流动控制方法来实现各种分析应用。本研究提出了几种可用于层压式基于毛细作用力的微流控装置的新型流动控制方法，以增加其功能。首先，我们引入了可停止和启动流动的推注和爆裂阀系统。这些阀可停止流动超过 30 分钟，通过按压通道或向阀区流入其他流体即可打开。接下来，我们提出了 Y 型通道的流动控制方法，可实现更多功能。在一个示例中，我们展示了精确控制浓度以创建层流、梯度和完全混合流的能力。在另一个示例中，通过调整入口通道的长度来控制主流道中的流速。此外，随着入口长度的增加，流速保持恒定。最后，还研究了 Y 型装置中的流速与通道高度以及诸如粘度和表面张力等流体性质之间的关系。与之前关于基于毛细作用力的通道的研究一样，流速受到每个参数的影响。本文提出的流体控制工具将为各种领域的低成本即时检测提供新的设计和功能。
