Active microdroplet merging by hydrodynamic flow control using a pneumatic actuator-assisted pillar structure

Dong Hyun Yoon*, Afshan Jamshaid, Junichi Ito, Asahi Nakahara, Daiki Tanaka, Takashiro Akitsu, Tetsushi Sekiguchi, Shuichi Shoji

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


This paper describes a microdroplet merging device that can actively control the merging of various droplets under a wide range of flow conditions, using a simple structure. The microdroplets were trapped and merged in a wide chamber divided by pillars, and their behavior was controlled by two horizontal pneumatic microactuators. Hydrodynamic flow control by the actuation was evaluated numerically, and the trapping and merging of droplets were achieved experimentally and controlled via pressure applied to the microactuators. Furthermore, two independently generated droplets were merged under four different modes, ranging from no merging to four-droplet merging, with different ratios and volumes. The pneumatic actuators allowed not only the control of the number of merged droplets, but also a wide range of applied droplet volumes. The device was fabricated simply using a single-layer PDMS (polydimethylsiloxane) structure, and the continuous merging performance operated using only hydrodynamic flow control without any surfactant. Finally, chemical synthesis of a metal complex was performed by the droplet merging method. Crystallization of the complex was visualized in real time, and the synthesis was verified by ultraviolet-visible spectroscopy.

Original languageEnglish
Pages (from-to)3050-3055
Number of pages6
JournalLab on a Chip
Issue number16
Publication statusPublished - 2014 Aug 21

ASJC Scopus subject areas

  • Bioengineering
  • Biochemistry
  • General Chemistry
  • Biomedical Engineering


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