Flexible manipulation of microfluids using optically regulated adsorption/desorption of hydrophobic materials

Hidenori Nagai*, Takashi Irie, Junko Takahashi, Shin ichi Wakida

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)


To realize highly integrated micro total analysis systems (μTAS), a simply controlled miniaturized valve should be utilized on microfluidic device. In this paper, we describe the application of photo-induced super-hydrophilicity of titanium dioxide (TiO2) to microfluidic manipulation. In addition, we found a new phenomenon for reversibly converting the surface wettability using a polydimethylsiloxane (PDMS) matrix and the photocatalytic properties of TiO2. While PDMS polymer was irradiated with UV, it was confirmed that hydrophobic material was released from the polymer to air. Several prepolymers were identified as the hydrophobic material with a gas chromatograph and mass spectrometer (GC/MS). Here, we successfully demonstrated the flexible manipulation of microfluid in a branched microchannel using the reversible wettability as micro opto-switching valve (MOS/V). The simultaneous control of MOS/Vs was also demonstrated on a 256-MOS/V integrated disk. The MOS/V promises to be one of the most effective flow switching valves for advanced applications in highly integrated micro/nano fluidics.

Original languageEnglish
Pages (from-to)1968-1973
Number of pages6
JournalBiosensors and Bioelectronics
Issue number9-10
Publication statusPublished - 2007 Apr 15
Externally publishedYes


  • Microvalve
  • Photocatalysis
  • Photodesorption
  • Super-hydrophilic
  • Surface wettability
  • Titanium dioxide

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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