Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St., Toronto, ON M5S 3G9, Canada.
Lab Chip. 2012 Feb 7;12(3):627-34. doi: 10.1039/c2lc20893h. Epub 2011 Dec 8.
Digital microfluidics (DMF), a fluid-handling technique in which picolitre-microlitre droplets are manipulated electrostatically on an array of electrodes, has recently become popular for applications in chemistry and biology. DMF devices are reconfigurable, have no moving parts, and are compatible with conventional high-throughput screening infrastructure (e.g., multiwell plate readers). For these and other reasons, digital microfluidics has been touted as being a potentially useful new tool for applications in multiplexed screening. Here, we introduce the first digital microfluidic platform used to implement parallel-scale cell-based assays. A fluorogenic apoptosis assay for caspase-3 activity was chosen as a model system because of the popularity of apoptosis as a target for anti-cancer drug discovery research. Dose-response profiles of caspase-3 activity as a function of staurosporine concentration were generated using both the digital microfluidic method and conventional techniques (i.e., pipetting, aspiration, and 96-well plates.) As expected, the digital microfluidic method had a 33-fold reduction in reagent consumption relative to the conventional technique. Although both types of methods used the same detector (a benchtop multiwell plate reader), the data generated by the digital microfluidic method had lower detection limits and greater dynamic range because apoptotic cells were much less likely to de-laminate when exposed to droplet manipulation by DMF relative to pipetting/aspiration in multiwell plates. We propose that the techniques described here represent an important milestone in the development of digital microfluidics as a useful tool for parallel cell-based screening and other applications.
数字微流控（DMF）是一种在电极阵列上通过静电操纵皮升至微升级液滴的流体处理技术，最近在化学和生物学领域的应用中变得非常流行。DMF 设备具有可重构性、无移动部件，并且与传统的高通量筛选基础设施（例如，多孔板读板器）兼容。由于这些原因以及其他原因，数字微流控被吹捧为在多重筛选应用中可能是一种有用的新工具。在这里，我们介绍了第一个用于实现基于细胞的平行规模测定的数字微流控平台。选择荧光法细胞凋亡测定法来测定 caspase-3 活性，因为细胞凋亡作为抗癌药物发现研究的靶标非常受欢迎。使用数字微流控方法和传统技术（即移液、抽吸和 96 孔板）生成了 caspase-3 活性作为 staurosporine 浓度的剂量反应曲线。如预期的那样，与传统技术相比，数字微流控方法的试剂消耗减少了 33 倍。尽管这两种类型的方法都使用相同的检测器（台式多微孔板读板器），但数字微流控方法生成的数据具有更低的检测限和更大的动态范围，因为与在多微孔板中进行移液/抽吸相比，在 DMF 下暴露于液滴操纵的凋亡细胞更不容易去分层。我们提出，这里描述的技术代表了数字微流控作为用于平行基于细胞的筛选和其他应用的有用工具的重要里程碑。
