Stretchable, wireless sensors and functional substrates for epidermal characterization of sweat

Xian Huang, Yuhao Liu, Kaile Chen, Woo Jung Shin, Ching Jui Lu, Gil Woo Kong, Dwipayan Patnaik, Sang Heon Lee, Jonathan Fajardo Cortes, John A. Rogers*

*Corresponding author for this work

Research output: Contribution to journalArticle

150 Scopus citations

Abstract

This paper introduces materials and architectures for ultrathin, stretchable wireless sensors that mount on functional elastomeric substrates for epidermal analysis of biofluids. Measurement of the volume and chemical properties of sweat via dielectric detection and colorimetry demonstrates some capabilities. Here, inductively coupled sensors consisting of LC resonators with capacitive electrodes show systematic responses to sweat collected in microporous substrates. Interrogation occurs through external coils placed in physical proximity to the devices. The substrates allow spontaneous sweat collection through capillary forces, without the need for complex microfluidic handling systems. Furthermore, colorimetric measurement modes are possible in the same system by introducing indicator compounds into the depths of the substrates, for sensing specific components (OH-, H+, Cu+, and Fe2+) in the sweat. The complete devices offer Young's moduli that are similar to skin, thus allowing highly effective and reliable skin integration without external fixtures. Experimental results demonstrate volumetric measurement of sweat with an accuracy of 0.06 μL/mm2 with good stability and low drift. Colorimetric responses to pH and concentrations of various ions provide capabilities relevant to analysis of sweat. Similar materials and device designs can be used in monitoring other body fluids. This paper introduces materials and architectures for ultrathin, stretchable wireless sensors that mount on functional elastomeric substrates for epidermal analysis of biofluids. Experimental results demonstrate volumetric measurement of sweat with high accuracy as well as good stability and low drift. Colorimetric responses to pH and concentrations of various ions demonstrate capabilities relevant to chemical analysis of sweat.

Original languageEnglish (US)
Pages (from-to)3083-3090
Number of pages8
JournalSmall
Volume10
Issue number15
DOIs
StatePublished - Aug 13 2014

Keywords

  • epidermal electronics
  • flexible electronics
  • stretchable electronics
  • sweat sensor
  • wireless sensor

ASJC Scopus subject areas

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

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  • Cite this

    Huang, X., Liu, Y., Chen, K., Shin, W. J., Lu, C. J., Kong, G. W., Patnaik, D., Lee, S. H., Cortes, J. F., & Rogers, J. A. (2014). Stretchable, wireless sensors and functional substrates for epidermal characterization of sweat. Small, 10(15), 3083-3090. https://doi.org/10.1002/smll.201400483