Confocal microscopic evaluation of mixing performance for three-dimensional microfluidic mixer

Takao Yasui, Yusuke Omoto, Keiko Osato, Noritada Kaji, Norikazu Suzuki, Toyohiro Naito, Yukihiro Okamoto, Manabu Tokeshi, Eiji Shamoto, Yoshinobu Baba

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


We developed a confocal microscopic method for a quantitative evaluation of the mixing performance of a three-dimensional microfluidic mixer. We fabricated a microfluidic baker's transformation (MBT) mixer as a three-dimensional passive-type mixer for the efficient mixing of solutions. Although the MBT mixer is one type of ideal mixers, it is hard to evaluate its mixing performance, since the MBT mixer is based on several cycles of complicated three-dimensional microchannel structures. We applied the method developed here to evaluate the mixing of water and a fluorescein isothiocyanate (FITC; diffusion coefficient, 4.9 × 10-10 m2 s-1) solution by the MBT mixer. This method enables us to capture vertical section images for the fluid distributions of FITC and water at different three-dimensional microchannel structures of the MBT device. These images are in good agreement with those of mixing images based on numerical simulations. The mixing ratio could be calculated by the fluorescence intensity at each pixel of the vertical section image; complete mixing is recognized by a mixing ratio of more than 90%. The mixing ratios are measured at different cycles of the MBT mixer by changing the flow rate; the mixing performance is evaluated by comparisons with the mixing ratio of the straight microchannel without the MBT mixer.

Original languageEnglish
Pages (from-to)57-60
Number of pages4
Journalanalytical sciences
Issue number1
Publication statusPublished - 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry


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