[Applied Materials and Interfaces] Continuously electrotriggered core coalescence of double-emulsion
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; then, we transfer the emulsion drops into another electrode integrated PDMS 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 controlled triggering of microreactions with high flexibility for a wide range of applications, especially for continuous chemical or cell assays.
Likai Hou, Yukun Ren, Yankai Jia, Xiaokang Deng, Weiyu Liu, Xiangsong Feng, and Hongyuan Jiang ACS Appl. Mater. Interfaces, Just Accepted Manuscript DOI: 10.1021/acsami.7b00670 Publication Date (Web): March 27, 2017 Copyright © 2017 American Chemical Society