title: Continuously Electrotriggered Core Coalescence of Double-Emulsion Drops for Microreactions.
abstract: 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.
authors.affiliation: School of Mechatronics Engineering and ‡State Key Laboratory of Robotics and System, Harbin Institute of Technology , Harbin 150001, PR China.
authors.forename: Likai
authors.identifier: http://orcid.org/0000-0003-3945-9006
authors.initials: L
authors.lastname: Hou
authors.affiliation: School of Mechatronics Engineering and ‡State Key Laboratory of Robotics and System, Harbin Institute of Technology , Harbin 150001, PR China.
authors.forename: Yukun
authors.identifier: http://orcid.org/0000-0002-0167-1274
authors.initials: Y
authors.lastname: Ren
authors.affiliation: School of Mechatronics Engineering and ‡State Key Laboratory of Robotics and System, Harbin Institute of Technology , Harbin 150001, PR China.
authors.forename: Yankai
authors.initials: Y
authors.lastname: Jia
authors.affiliation: School of Mechatronics Engineering and ‡State Key Laboratory of Robotics and System, Harbin Institute of Technology , Harbin 150001, PR China.
authors.forename: Xiaokang
authors.initials: X
authors.lastname: Deng
authors.affiliation: School of Mechatronics Engineering and ‡State Key Laboratory of Robotics and System, Harbin Institute of Technology , Harbin 150001, PR China.
authors.forename: Weiyu
authors.initials: W
authors.lastname: Liu
authors.affiliation: School of Mechatronics Engineering and ‡State Key Laboratory of Robotics and System, Harbin Institute of Technology , Harbin 150001, PR China.
authors.forename: Xiangsong
authors.initials: X
authors.lastname: Feng
authors.affiliation: School of Mechatronics Engineering and ‡State Key Laboratory of Robotics and System, Harbin Institute of Technology , Harbin 150001, PR China.
authors.forename: Hongyuan
authors.initials: H
authors.lastname: Jiang
mesh_terms: D004655:Emulsions / Q000737:chemistry*; D020100:Hydrogels
chemical_list: D004655:Emulsions; D020100:Hydrogels
keywords: double emulsion; droplet; electrocoalescence; microfluidics; microreactor