Droplet-based microreactions with oil encapsulation

Chuang Yuan Lee, Hongyu Yu, Wei Pang, Eun Sok Kim

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


This paper reports a microreaction technology for biochemical assay using nanoliter droplets encapsulated inside oil droplets. Microreaction chambers are constructed on a glass substrate by accumulating oil droplets that are dispensed by a directional droplet ejector. Droplets of different aqueous reagents are then directionally ejected (by other directional droplet ejector adjacent to the oil droplet ejector) into the oil microchambers for parallel and combinatory analysis. Because the reagents are encapsulated in oil, the evaporation rate is reduced by several orders of magnitude, and only small amounts of reagents are required for each assay. The microchamber size and the reagent amount are digitally controlled by the number of ejected oil and reagent droplets, respectively. The ejectors for oil and reagents have been integrated on a single chip so that each assay is performed efficiently without any mechanical movement and alignment. We have carried out both physical and chemical microreactions with this method and observed a negligible difference in response from conventional macroreactions.

Original languageEnglish (US)
Pages (from-to)147-156
Number of pages10
JournalJournal of Microelectromechanical Systems
Issue number1
StatePublished - Feb 2008


  • Acoustic devices
  • Microactuators

ASJC Scopus subject areas

  • Mechanical Engineering
  • Electrical and Electronic Engineering


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