Resettable sweat-powered wearable electrochromic biosensor

Martin C Hartel; Dongwook Lee; Paul S Weiss; Joseph Wang; Jayoung Kim

doi:10.1016/j.bios.2022.114565

Resettable sweat-powered wearable electrochromic biosensor

Biosens Bioelectron. 2022 Nov 1:215:114565. doi: 10.1016/j.bios.2022.114565. Epub 2022 Jul 13.

Authors

Martin C Hartel¹, Dongwook Lee², Paul S Weiss³, Joseph Wang⁴, Jayoung Kim⁵

Affiliations

¹ Department of Nanoengineering, University of California, San Diego, La Jolla, CA, 92093, USA; Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
² Department of Medical Engineering, College of Medicine, Yonsei University, Seoul, 03722, South Korea.
³ Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA; Department of Chemistry & Biochemistry, Department of Materials Science & Engineering, and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
⁴ Department of Nanoengineering, University of California, San Diego, La Jolla, CA, 92093, USA. Electronic address: josephwang@eng.ucsd.edu.
⁵ Department of Medical Engineering, College of Medicine, Yonsei University, Seoul, 03722, South Korea. Electronic address: jayoungkim@yonsei.ac.kr.

PMID: 35926393
DOI: 10.1016/j.bios.2022.114565

Abstract

Wearable biofuel cells (BFCs) are being widely studied as self-powered sensors to monitor one's physiological status non-invasively. However, the energy generated by such devices is often insufficient to power accompanying measurement read-out systems and communication protocols. Here, we report a reversible fully printed electrochromic self-powered sensor (ESPS) toward on-body sweat lactate monitoring. The device was realized by integrating a lactate-oxidizable BFC anode, oxygen-reducible BFC cathode, and a reversible Prussian blue (PB) electrochromic display on a single wearable patch. Through modification of the BFC electrodes, the formal potential of the PB display (0.14 V) could be positioned in between the potentials of the lactate oxidation (-0.05 V) and oxygen reduction (0.35 V). Based on this system, the ESPS enables reversible and robust color changes with distinct time- and concentration-dependent profiles. The results demonstrate that the self-powered device has practical on-body applications for continual lactate monitoring with several advantages, including facile reversibility, ease of fabrication, and naked-eye colorimetric read-out.

Keywords: Biofuel cell; Electrochromic; Epidermal biosensor; Self-powered; Sweat; Wearable electronics.

MeSH terms

Biosensing Techniques* / methods
Lactic Acid
Oxygen
Sweat
Wearable Electronic Devices*

Substances

Lactic Acid
Oxygen