Open-channel microfluidics via resonant wireless power transfer

Christopher Ertsgaard, Daehan Yoo, Peter R. Christenson, Daniel J. Klemme, Sang Hyun Oh

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Open-channel microfluidics enables precise positioning and confinement of liquid volume to interface with tightly integrated optics, sensors, and circuit elements. Active actuation via electric fields can offer a reduced footprint compared to passive microfluidic ensembles and removes the burden of intricate mechanical assembly of enclosed systems. Typical systems actuate via manipulating surface wettability (i.e., electrowetting), which can render low-voltage but forfeits open-microchannel confinement. The dielectric polarization force is an alternative which can generate open liquid microchannels (sub-100 µm) but requires large operating voltages (50–200 VRMS) and low conductivity solutions. Here we show actuation of microchannels as narrow as 1 µm using voltages as low as 0.5 VRMS for both deionized water and physiological buffer. This was achieved using resonant, nanoscale focusing of radio frequency power and an electrode geometry designed to abate surface tension. We demonstrate practical fluidic applications including open mixing, lateral-flow protein labeling, filtration, and viral transport for infrared biosensing—known to suffer strong absorption losses from enclosed channel material and water. This tube-free system is coupled with resonant wireless power transfer to remove all obstructing hardware — ideal for high-numerical-aperture microscopy. Wireless, smartphone-driven fluidics is presented to fully showcase the practical application of this technology.

Original languageEnglish (US)
Article number1869
JournalNature communications
Issue number1
StatePublished - Apr 2022

Bibliographical note

Funding Information:
This research was supported by the National Science Foundation (NSF ECCS 1610333). C.T.E. and D.J.K. acknowledge support from the NSF Graduate Research Fellowship Program. S.-H.O. further acknowledges support from the Sanford P. Bordeau Endowed Chair at the University of Minnesota and the McKnight Foundation. Device fabrication was performed in the Minnesota Nano Center at the University of Minnesota, which is supported by the NSF through the National Nanotechnology Coordinated Infrastructure (NNCI) under Award Number ECCS-1542202. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the NSF through the MRSEC program.

Publisher Copyright:
© 2022, The Author(s).

MRSEC Support

  • Shared

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.


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