Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 01238, USA.
Anal Chem. 2009 Mar 15;81(6):2399-402. doi: 10.1021/ac8026542.
This paper describes a method to control the volume and the velocity of drops generated in a flow-focusing device dynamically and independently. This method involves simultaneous tuning of the temperature of the nozzle of the device and of the flow rate of the continuous phase; the method requires a continuous phase liquid that has a viscosity that varies steeply with temperature. Increasing the temperature of the flow-focusing nozzle from 0 to 80 degrees C increased the volume of the drops by almost 2 orders of magnitude. Tuning both the temperature and the flow rate controlled the drop volume and the drop velocity independently; this feature is not possible in a basic flow-focusing device. This paper also demonstrates a procedure for identifying the range of possible drop volumes and drop velocities for a given flow-focusing device and shows how to generate drops with a specified volume and velocity within this range. This method is easy to implement in on-chip applications where thermal management is already incorporated in the system, such as DNA amplification using the polymerase chain reaction and nanoparticle synthesis.
本文介绍了一种在流聚焦装置中动态且独立地控制液滴体积和速度的方法。该方法涉及同时调节装置喷嘴的温度和连续相的流速；该方法需要使用具有随温度急剧变化的粘度的连续相液体。将流聚焦喷嘴的温度从 0 度升高到 80 度，可使液滴体积增加近 2 个数量级。同时调节温度和流速可以独立控制液滴体积和速度；这在基本的流聚焦装置中是不可能实现的。本文还演示了一种确定给定流聚焦装置可能的液滴体积和速度范围的方法，并展示了如何在该范围内生成具有指定体积和速度的液滴。该方法易于在已经在系统中纳入热管理的芯片应用中实现，例如使用聚合酶链反应进行 DNA 扩增和纳米颗粒合成。
