Soft, Skin-Interfaced Microfluidic Systems with Wireless, Battery-Free Electronics for Digital, Real-Time Tracking of Sweat Loss and Electrolyte Composition

Sung Bong Kim, Kun Hyuck Lee, Milan S. Raj, Boram Lee, Jonathan T. Reeder, Jahyun Koo, Aurélie Hourlier-Fargette, Amay J. Bandodkar, Sang Min Won, Yurina Sekine, Jungil Choi, Yi Zhang, Jangryeol Yoon, Bong Hoon Kim, Yeojeong Yun, Seojin Lee, Jiho Shin, Jeonghyun Kim, Roozbeh Ghaffari, John A. Rogers*

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Sweat excretion is a dynamic physiological process that varies with body position, activity level, environmental factors, and health status. Conventional means for measuring the properties of sweat yield accurate results but their requirements for sampling and analytics do not allow for use in the field. Emerging wearable devices offer significant advantages over existing approaches, but each has significant drawbacks associated with bulk and weight, inability to quantify volumetric sweat rate and loss, robustness, and/or inadequate accuracy in biochemical analysis. This paper presents a thin, miniaturized, skin-interfaced microfluidic technology that includes a reusable, battery-free electronics module for measuring sweat conductivity and rate in real-time using wireless power from and data communication to electronic devices with capabilities in near field communications (NFC), including most smartphones. The platform exploits ultrathin electrodes integrated within a collection of microchannels as interfaces to circuits that leverage NFC protocols. The resulting capabilities are complementary to those of previously reported colorimetric strategies. Systematic studies of these combined microfluidic/electronic systems, accurate correlations of measurements performed with them to those of laboratory standard instrumentation, and field tests on human subjects exercising and at rest establish the key operational features and their utility in sweat analytics.

Original languageEnglish (US)
Article number1802876
JournalSmall
Volume14
Issue number45
DOIs
StatePublished - Nov 8 2018

Keywords

  • flexible electrodes
  • microfluidics
  • near field communication
  • sweat conductivity

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)

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  • Cite this

    Kim, S. B., Lee, K. H., Raj, M. S., Lee, B., Reeder, J. T., Koo, J., Hourlier-Fargette, A., Bandodkar, A. J., Won, S. M., Sekine, Y., Choi, J., Zhang, Y., Yoon, J., Kim, B. H., Yun, Y., Lee, S., Shin, J., Kim, J., Ghaffari, R., & Rogers, J. A. (2018). Soft, Skin-Interfaced Microfluidic Systems with Wireless, Battery-Free Electronics for Digital, Real-Time Tracking of Sweat Loss and Electrolyte Composition. Small, 14(45), [1802876]. https://doi.org/10.1002/smll.201802876