Graphene e-tattoos for unobstructive ambulatory electrodermal activity sensing on the palm enabled by heterogeneous serpentine ribbons

Hongwoo Jang; Kaan Sel; Eunbin Kim; Sangjun Kim; Xiangxing Yang; Seungmin Kang; Kyoung-Ho Ha; Rebecca Wang; Yifan Rao; Roozbeh Jafari; Nanshu Lu

doi:10.1038/s41467-022-34406-2

Graphene e-tattoos for unobstructive ambulatory electrodermal activity sensing on the palm enabled by heterogeneous serpentine ribbons

Nat Commun. 2022 Nov 3;13(1):6604. doi: 10.1038/s41467-022-34406-2.

Authors

Hongwoo Jang¹, Kaan Sel², Eunbin Kim¹, Sangjun Kim³, Xiangxing Yang⁴, Seungmin Kang⁵, Kyoung-Ho Ha³, Rebecca Wang⁶, Yifan Rao⁶, Roozbeh Jafari^{2

7

8}, Nanshu Lu^{9

10

11

12

13}

Affiliations

¹ Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA.
² Department of Electrical and Computer Engineering at Texas A&M University, College Station, TX, 77843, USA.
³ Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
⁴ Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
⁵ Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
⁶ Department of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin, Austin, TX, 78712, USA.
⁷ Department of Biomedical Engineering at Texas A&M University, College Station, TX, 77843, USA.
⁸ Department of Computer Science and Engineering at Texas A&M University, College Station, TX, 77843, USA.
⁹ Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA. nanshulu@utexas.edu.
¹⁰ Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA. nanshulu@utexas.edu.
¹¹ Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA. nanshulu@utexas.edu.
¹² Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA. nanshulu@utexas.edu.
¹³ Department of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin, Austin, TX, 78712, USA. nanshulu@utexas.edu.

Abstract

Electrodermal activity (EDA) is a popular index of mental stress. State-of-the-art EDA sensors suffer from obstructiveness on the palm or low signal fidelity off the palm. Our previous invention of sub-micron-thin imperceptible graphene e-tattoos (GET) is ideal for unobstructive EDA sensing on the palm. However, robust electrical connection between ultrathin devices and rigid circuit boards is a long missing component for ambulatory use. To minimize the well-known strain concentration at their interfaces, we propose heterogeneous serpentine ribbons (HSPR), which refer to a GET serpentine partially overlapping with a gold serpentine without added adhesive. A fifty-fold strain reduction in HSPR vs. heterogeneous straight ribbons (HSTR) has been discovered and understood. The combination of HSPR and a soft interlayer between the GET and an EDA wristband enabled ambulatory EDA monitoring on the palm in free-living conditions. A newly developed EDA event selection policy leveraging unbiased selection of phasic events validated our GET EDA sensor against gold standards.

Publication types

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

MeSH terms

Galvanic Skin Response
Graphite*
Monitoring, Ambulatory
Tattooing*

Substances

Graphite