Microsystem Technologies

, Volume 12, Issue 3, pp 238–246 | Cite as

A microfluidic gel valve device using reversible sol–gel transition of methyl cellulose for biomedical application

Technical paper

Abstract

We have fabricated a microfluidic gel valve device that used reversible sol–gel transition of methyl cellulose (MC). A microheater and a microtemperature sensor were implemented in each microchannel in the gel valve device. Before evaluating the performance of the gel valve device, various properties of the MC solution were investigated using viscometer, spectrophotometer, and NMR. Gelation temperature was increased as the MC concentration was increased. Clear gel, an intermediate state between clear sol and turbid gel, was found at the temperature range from 30–40°C to 50–60°C. Temperature at each microchannel of the device was measured and the effect of the temperature difference on the valve operation was elucidated. In order to have normal operation of the gel valve, it was important to keep the temperature of the heated microchannel around 60°C while keeping the temperature of the flowing microchannel below 35°C. The temperature difference between two microchannels was about 23 K when fan forced cooling (FFC) method was used. For normal performance of the gel valve device, a temporary pause of fluid flow for at least 5 s was required to complete the local gelation in the microchannel. Stable gel valve performance was obtained at the flow rates larger than 5 μl/min. The gel valve device showed no leakage up to 2.07×104 Pa.

Keywords

Methyl cellulose Sol–gel Gel valve BioMEMS 

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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Dae Sung Yoon
    • 1
  • Yoon-Kyoung Cho
    • 2
  • Kwang W. Oh
    • 2
  • Sunhee Kim
    • 3
  • Young Ah Kim
    • 1
  • Jung Im Han
    • 1
  • Geunbae Lim
    • 4
  1. 1.Bio-MEMS Laboratory, Microsystem Research CenterKorea Institute of Science and TechnologySeoulKorea
  2. 2.Digital Bio LaboratorySamsung Advanced Institute of TechnologyKyunggi-doKorea
  3. 3.Department of Chemistry, Surface Science CenterUniversity of PittsburghPittsburghUSA
  4. 4.Department of Mechanical EngineeringPohang University of Science and TechnologyKyungbookKorea

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