School of Mechatronics Engineering and ‡State Key Laboratory of Robotics and System, Harbin Institute of Technology , Harbin 150001, PR China.
ACS Appl Mater Interfaces. 2017 Apr 12;9(14):12282-12289. doi: 10.1021/acsami.7b00670. Epub 2017 Mar 30.
Microfluidically generated double emulsions are promising templates for microreactions, which protect the reaction from external disturbance and enable in vitro analyses with large-scale samples. Controlled combination of their inner droplets in a continuous manner is an essential requirement toward truly applications. Here, we first generate dual-cored double-emulsion drops with different inner encapsulants using a capillary microfluidic device; next, we transfer the emulsion drops into another electrode-integrated polydimethylsiloxane microfluidic device and utilize external AC electric field to continuously trigger the coalescence of inner cores inside these emulsion drops in continuous flow. Hundreds of thousands of monodisperse microreactions with nanoliter-scale reagents can be conducted using this approach. The performance of core coalescence is investigated as a function of flow rate, applied electrical signal, and core conductivity. The coalescence efficiency can reach up to 95%. We demonstrate the utility of this technology for accommodating microreactions by analyzing an enzyme catalyzed reaction and by fabricating cell-laden hydrogel particles. The presented method can be readily used for the controlled triggering of microreactions with high flexibility for a wide range of applications, especially for continuous chemical or cell assays.
微流控生成的双乳液是微反应的有前途的模板，它可以保护反应免受外部干扰，并能够对大规模样品进行体外分析。以连续的方式控制它们的内部液滴的组合是真正应用的基本要求。在这里，我们首先使用毛细管微流控装置生成具有不同内包封剂的双核双乳液滴；接下来，我们将乳液滴转移到另一个集成电极的聚二甲基硅氧烷微流控装置中，并利用外部交流电场连续触发这些乳液滴内的内芯在连续流动中的聚结。使用这种方法可以进行数十万次具有纳升级试剂的单分散微反应。研究了核聚结作为流速、施加的电信号和核电导率函数的性能。聚结效率最高可达 95%。我们通过分析酶催化反应和制造载细胞水凝胶颗粒来证明该技术在容纳微反应方面的实用性。该方法可用于以高灵活性控制触发各种应用的微反应，特别是用于连续化学或细胞分析。
