Microfluidic chip with integrated microvalves based on temperature- and pH-responsive hydrogel thin films

Authors

  • M. Bäcker,

    1. Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, 52428 Jülich, Germany
    2. Peter Grünberg Institute (PGI-8), Research Centre Jülich, 52425 Jülich, Germany
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    • Both the authors contributed equally to this work.

  • M. Raue,

    1. Institute of Applied Polymer Chemistry (IAP), Aachen University of Applied Sciences, 52428 Jülich, Germany
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    • Both the authors contributed equally to this work.

  • S. Schusser,

    1. Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, 52428 Jülich, Germany
    2. Peter Grünberg Institute (PGI-8), Research Centre Jülich, 52425 Jülich, Germany
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  • C. Jeitner,

    1. Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, 52428 Jülich, Germany
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  • L. Breuer,

    1. Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, 52428 Jülich, Germany
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  • P. Wagner,

    1. Institute for Materials Research, Hasselt University, 3590 Diepenbeek, Belgium
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  • A. Poghossian,

    1. Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, 52428 Jülich, Germany
    2. Peter Grünberg Institute (PGI-8), Research Centre Jülich, 52425 Jülich, Germany
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  • A. Förster,

    1. Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, 52428 Jülich, Germany
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  • T. Mang,

    1. Institute of Applied Polymer Chemistry (IAP), Aachen University of Applied Sciences, 52428 Jülich, Germany
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  • M. J. Schöning

    Corresponding author
    1. Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, 52428 Jülich, Germany
    2. Peter Grünberg Institute (PGI-8), Research Centre Jülich, 52425 Jülich, Germany
    • Phone: +49-241-6009-53215, Fax: +49-241-6009-53235
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Abstract

Two types of microvalves based on temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) and pH-responsive poly(sodium acrylate) (PSA) hydrogel films have been developed and tested. The PNIPAAm and PSA hydrogel films were prepared by means of in situ photopolymerization directly inside the fluidic channel of a microfluidic chip fabricated by combining Si and SU-8 technologies. The swelling/shrinking properties and height changes of the PNIPAAm and PSA films inside the fluidic channel were studied at temperatures of deionized water from 14 to 36 °C and different pH values (pH 3–12) of Titrisol buffer, respectively. Additionally, in separate experiments, the lower critical solution temperature (LCST) of the PNIPAAm hydrogel was investigated by means of a differential scanning calorimetry (DSC) and a surface plasmon resonance (SPR) method. Mass-flow measurements have shown the feasibility of the prepared hydrogel films to work as an on-chip integrated temperature- or pH-responsive microvalve capable to switch the flow channel on/off.

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