Yates Alexis K, Murray Heather N, Lippmann Ethan S
Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, TN, USA.
Chemical and Biomolecular Engineering Department, Vanderbilt University, Nashville, TN, USA.
SLAS Technol. 2025 Jun;32:100305. doi: 10.1016/j.slast.2025.100305. Epub 2025 May 10.
Microfluidic devices are defined by the application of fluid flow to micron-scale features. Inherent to most experiments involving microfluidic devices is the need to precisely and reproducibly control fluid flow at the microliter scale, often through multiple inlet ports on a single device. While the number of fluid channels per device varies, perfusing multiple inputs requires either the use of multiple flow controllers (often syringe or peristaltic pumps) or the ability to evenly divide fluid across outlets. Towards the latter approach, while a handful of commercial systems exist for splitting fluid flow, these set-ups require significant financial investment, multiple flow control and sensing components, and restrict the user to a predetermined perfusion control system. Simple in-line splitting devices, such a manifolds or T junctions, fail to achieve flow splitting at low flow rates often used in microfluidic systems. To increase capabilities for flow-controlled experiments, we performed experimental analyses of the physical considerations governing even flow splitting under low flow, leading to the design of a microdevice (µ-Split) that can be directly inserted into existing microfluidic set-ups. The µ-Split allows for reproducible, even flow splitting from 10 uL/min to > 2.5 mL/min. By testing multiple device geometries in combination with multiphysics simulations, we identified the design and fabrication features underlying the splitting precision achieved by the µ-Split. Overall, this work provides a useful tool to simplify microfluidic experiments that require evenly divided flow streams, while minimizing the overall device footprint.
微流控设备是通过将流体流动应用于微米级特征来定义的。大多数涉及微流控设备的实验都需要在微升尺度上精确且可重复地控制流体流动，通常是通过单个设备上的多个入口端口来实现。虽然每个设备的流体通道数量各不相同，但灌注多个输入需要使用多个流量控制器（通常是注射器或蠕动泵），或者需要具备在多个出口之间均匀分配流体的能力。对于后一种方法，虽然有少数商业系统可用于分流流体，但这些设置需要大量资金投入、多个流量控制和传感组件，并且限制用户只能使用预定的灌注控制系统。简单的在线分流设备，如歧管或T型接头，在微流控系统常用的低流速下无法实现分流。为了提高流量控制实验的能力，我们对低流量下均匀分流的物理因素进行了实验分析，从而设计出一种可直接插入现有微流控装置的微型设备（µ-Split）。µ-Split能够在10微升/分钟至>2.5毫升/分钟的范围内实现可重复的均匀分流。通过测试多种设备几何形状并结合多物理场模拟，我们确定了µ-Split实现分流精度的设计和制造特征。总体而言，这项工作提供了一个有用的工具，可简化需要均匀分流的微流控实验，同时将整个设备占地面积最小化。
