Dielectrowetting manipulation for digital microfluidics: creating, transporting, splitting, and merging of droplets
Dielectrowetting manipulation for digital microfluidics: creating, transporting, splitting, and merging of droplets
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DOI：
10.1039/c7lc00006e
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发表时间：
2017-03-21
期刊：
影响因子：
6.1
通讯作者：
Cho, Sung Kwon
中科院分区：
文献类型：
--
作者：
Geng, Hongyao;Feng, Jian;Cho, Sung Kwon
生成、分裂、传输和合并液滴是数字（基于液滴）微流体的基本和关键单元操作。最先进的数字微流体通常在两个平行通道板的典型配置中使用电介质上电润湿（EWOD）来执行这样的操作。本文介绍了这样的操作使用介电润湿（来自液体介电泳），而不是EWOD，与叉指电极阵列。主要和独特的特征是，本液滴操纵对于导电（具有/不具有表面活性剂的水）和非导电（碳酸丙烯酯）流体是有效的。一个同样重要的方面是，操作是在没有覆盖顶板的开放空间中进行的。这种行为归因于介电润湿的固有性质，以产生比EWOD更强的润湿力（具有实现接触角= 0（Ω）的完全润湿以形成薄膜的能力）。使用介电润湿，从大液滴产生各种体积的微液滴并输送。即使当液滴小于电极垫时，也实现了分离单个液滴以及多个液滴并合并它们。上述分离、运输和合并操作对于碳酸亚丙酯以及具有/不具有表面活性剂的DI水是有效的，尽管目前仅证明了产生操作对于碳酸亚丙酯。上述操作均在一个平板上成功地完成，不仅简化了结构和操作过程，而且消除了对处理流体体积的限制。
Generating, splitting, transporting, and merging droplets are fundamental and critical unit operations for digital (droplet-based) microfluidics. State-of-the-art digital microfluidics performs such operations commonly using electrowetting-on-dielectric (EWOD) in the typical configuration of two parallel channel plates. This paper presents such operations using dielectrowetting (derived from liquid dielectrophoresis), not EWOD, with an array of interdigitated electrodes. The major and unique feature is that the present droplet manipulations are effective for conductive (water with/without surfactant) and non-conductive (propylene carbonate) fluids. An equally important aspect is that the manipulations are performed in an open space without the covering top plate. This behavior is attributed to the intrinsic nature of dielectrowetting to generate stronger wetting forces than EWOD (with the ability to achieve complete wetting with contact angle = 0(omicron) to form a thin film). Using dielectrowetting, micro-droplets of various volumes are created from a large droplet and transported. Splitting a single droplet as well as multiple droplets and merging them are also achieved, even when the droplets are smaller than the electrode pads. The above splitting, transport, and merging operations are effective for propylene carbonate as well as DI water with/without surfactant, though the creating operation is proven only for propylene carbonate at this moment. All the above manipulations are successfully carried out on a single plate, which not only simplifies the structure and operation procedure, but could also eliminate the restriction to the volume of fluid handled.