Functional hydrogel structures for autonomous flow control inside microfluidic channels


Hydrogels have been developed to respond to a wide variety of stimuli1,2,3,4,5,6, but their use in macroscopic systems has been hindered by slow response times (diffusion being the rate-limiting factor governing the swelling process). However, there are many natural examples of chemically driven actuation that rely on short diffusion paths to produce a rapid response7. It is therefore expected that scaling down hydrogel objects to the micrometre scale should greatly improve response times. At these scales, stimuli-responsive hydrogels could enhance the capabilities of microfluidic systems by allowing self-regulated flow control. Here we report the fabrication of active hydrogel components inside microchannels via direct photopatterning of a liquid phase. Our approach greatly simplifies system construction and assembly as the functional components are fabricated in situ, and the stimuli-responsive hydrogel components perform both sensing and actuation functions. We demonstrate significantly improved response times (less than 10 seconds) in hydrogel valves capable of autonomous control of local flow.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: A diagram of the fabrication method and images demonstrating a variety of shapes that were polymerized within 35 seconds.
Figure 2: Prefabricated posts in a microchannel serve as supports for the hydrogels, improving stability during volume changes.
Figure 3: A shut-off valve.
Figure 4: The volume response of two different hydrogels with respect to the pH of the surrounding fluid.


  1. 1

    Tanaka,T. et al. Phase transitions in ionic gels. Phys. Rev. Lett. 45, 1636–1639 ( 1980).

    ADS  CAS  Article  Google Scholar 

  2. 2

    Hu,Z., Zhang,X. & Li,Y. Synthesis and application of modulated polymer gels. Science 269, 525–527 (1995).

    ADS  CAS  Article  Google Scholar 

  3. 3

    Tanaka,T., Nishio,I., Sun,S.-T. & Ueno-Nishio,S. Collapse of gels in an electric field. Science 218, 467–469 (1982).

    ADS  CAS  Article  Google Scholar 

  4. 4

    Suzuki,A. & Tanaka,T. Phase transition in polymer gels induced by visible light. Nature 346, 345– 347 (1990).

    ADS  CAS  Article  Google Scholar 

  5. 5

    Kataoka,K., Miyazaki,H., Bunya,M., Okano,T. & Sakurai,Y. Totally synthetic polymer gels responding to external glucose concentration: their preparation and application to on-off regulation of insulin release. J. Am. Chem. Soc. 120, 12694–12695 (1998).

    CAS  Article  Google Scholar 

  6. 6

    Miyata,T., Asami,N. & Uragami,T. A reversibly antigen-responsive hydrogel. Nature 399, 766–769 ( 1999).

    ADS  CAS  Article  Google Scholar 

  7. 7

    Schmidt-Nielsen,K. Animal Physiology (Cambridge Univ. Press, Cambridge, 1975).

    Google Scholar 

  8. 8

    Kovacs,G. T. A. Micromachined Transducers Sourcebook (WCB McGraw-Hill, Boston, 1998).

    Google Scholar 

  9. 9

    Trimmer,W. S. N. Microrobots and micromechanical systems. Sensors Actuators 19, 267–287 (1988).

    Article  Google Scholar 

  10. 10

    Smela,E., Inganäs,O. & Lundström,I. Controlled folding of micrometer-size structures. Science 268, 1735–1738 (1995).

    ADS  CAS  Article  Google Scholar 

  11. 11

    Breen,T., Tien,J., Oliver,S. R. J., Hadzic,T. & Witesides, G. M. Design and self-assembly of open, regular, 3D mesostructures. Science 284, 948–951 (1999).

    ADS  CAS  Article  Google Scholar 

  12. 12

    Jackman,R. J., Brittain,S. T., Adams,A., Prentiss,M. G. & Whitesides, G. M. Design and fabrication of topologically complex, three-dimensional microstructures. Science 280, 2089–2091 (1998).

    ADS  CAS  Article  Google Scholar 

  13. 13

    Kenis,P. J., Ismagilov,R. F. & Whitesides, G. M. Microfabrication inside capillaries using multiphase laminar flow patterning. Science 285, 83 –85 (1999).

    CAS  Article  Google Scholar 

  14. 14

    Cumpston,B. H. et al. Two-photon polymerization initiators for three-dimensional optical data storage and microfabrication. Nature 398 , 51–54 (1999).

    ADS  CAS  Article  Google Scholar 

  15. 15

    Jo,B.-H., Lerberghe,L. M. V., Motsegood, K. M. & Beebe,D. J. Three-dimensional micro-channel fabrication in polydimethylsiloxane (PDMS) elastomer. J. Micromech. Syst. 9, 76– 81 (1999).

    Article  Google Scholar 

Download references


This work was supported by DARPA-MTO.

Author information



Corresponding author

Correspondence to David J. Beebe.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Beebe, D., Moore, J., Bauer, J. et al. Functional hydrogel structures for autonomous flow control inside microfluidic channels. Nature 404, 588–590 (2000).

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.