Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON M5S 3G9, Canada.
Lab Chip. 2011 Feb 7;11(3):535-40. doi: 10.1039/c0lc00223b. Epub 2010 Oct 29.
Digital microfluidics (DMF) is a technique in which discrete droplets are manipulated by applying electrical fields to an array of electrodes. In an ideal DMF system, each application of driving potential would cause a targeted droplet to move onto an energized electrode (i.e., perfect fidelity between driving voltage and actuation); however, in real systems, droplets are sometimes observed to resist movement onto particular electrodes. Here, we implement a sensing and feedback control system in which all droplet movements are monitored, such that when a movement failure is observed, additional driving voltages can be applied until the droplet completes the desired operation. The new system was evaluated for a series of liquids including water, methanol, and cell culture medium containing fetal bovine serum, and feedback control was observed to result in dramatic improvements in droplet actuation fidelity and velocity. The utility of the new system was validated by implementing an enzyme kinetics assay with continuous mixing. The new platform for digital microfluidics is simple and inexpensive and thus should be useful for scientists and engineers who are developing automated analysis platforms.
数字微流控（DMF）是一种通过向电极阵列施加电场来操纵离散液滴的技术。在理想的 DMF 系统中，每次施加驱动电势都会导致目标液滴移动到通电电极上（即驱动电压和致动之间具有完美的保真度）；然而，在实际系统中，有时会观察到液滴抵抗移动到特定电极上。在这里，我们实现了一种传感和反馈控制系统，其中监测所有液滴运动，使得当观察到运动故障时，可以施加额外的驱动电压，直到液滴完成所需的操作。该新系统对一系列液体（包括水、甲醇和含有胎牛血清的细胞培养基）进行了评估，并且反馈控制导致液滴致动保真度和速度的显著提高。通过实施连续混合的酶动力学测定来验证新系统的实用性。新的数字微流控平台简单且价格低廉，因此对于开发自动化分析平台的科学家和工程师应该是有用的。
