On-site formation of emulsions by controlled air plugs

Xiaowen Huang, Wenli Hui, Chonglei Hao, Wanqing Yue, Mengsu Yang, Yali Cui, Zuankai Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

19 Citations (Scopus)

Abstract

Air plugs are usually undesirable in microfluidic systems because of their detrimental effect on the system's stability and integrity. By controlling the wetting properties as well as the topographical geometry of the microchannel, it is reported herein that air plugs can be generated in pre-defined locations to function as a unique valve, allowing for the on-site formation of various emulsions including single-component droplets, composite droplets with droplet-to-droplet concentration gradient, blood droplets, paired droplets, as well as bubble arrays without the need for precious flow control, a difficult task with conventional droplet microfluidics. Moreover, the self-generated air valve can be readily deactivated (turned off) by the introduction of an oil phase, allowing for the on-demand release of as-formed droplets for downstream applications. It is proposed that the simple, yet versatile nature of this technique can act as an important method for droplet microfluidics and, in particular, is ideal for the development of affordable lab-on-a-chip systems without suffering from scalability and manufacturing challenges that typically confound the conventional droplet microfluidics. Various emulsions including single-component droplets, composite droplets with droplet-to-droplet concentration gradient, blood droplets, paired droplets, as well as bubble arrays are formed in an on-site manner without the need for precious flow control. This method takes advantage of the valve nature of air plugs, which are usually undesirable in the microfluidic system because of their detrimental effect on the system's stability and integrity

Original languageEnglish
Pages (from-to)758-765
Number of pages8
JournalSmall
Volume10
Issue number4
DOIs
Publication statusPublished - 26 Feb 2014
Externally publishedYes

Keywords

  • droplet microfluidics
  • immobilization
  • point of care diagnostics
  • valve

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)

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