Multiple flow switch using stepwise sheath flow

Masaki Kanai*, Shin Ichiro Otsuka, Hiroaki Nakanishi, Shuichi Shoji

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


In this paper we present a concentration-conservative flow switch using a sheath flow. A novel concept of stepwise flow was proposed to prevent the sample dilution during flow switching. Computational fluid dynamics (CFD) simulations revealed that the stepwise flow suppressed a back flow of the sample reagent that caused the sample dilution. Based on the CFD simulation results, the prototype devices of the flow switch utilizing the stepwise flow were designed. Using fabricated devices, reduction of the sample dilution by the stepwise flow was confirmed. In order to reduce the switching time, pneumatic microvalves were integrated with the flow switch. Its characteristic of the switching time was evaluated experimentally. The switching time was about 130 ms, which was reduced to less than half compared to the case of using off-chip valves. In the case that the sample flow rate is 1 μL/min, it is expected that the flow switch will achieve fluid sampling with the accuracy of the order of nanoliters.

Original languageEnglish
Pages (from-to)3849-3854
Number of pages6
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number6 B
Publication statusPublished - 2004 Jun


  • CFD simulation
  • Flow switch
  • Sample dilution
  • Sheath flow
  • Stepwise flow
  • μTAS

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)


Dive into the research topics of 'Multiple flow switch using stepwise sheath flow'. Together they form a unique fingerprint.

Cite this