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Updated: Sep 2, 2025
A Detailed Protocol for Perspiration Monitoring Using a Novel, Small, Wireless Device
Published on: November 24, 2016
Resettable sweat-powered wearable electrochromic biosensor
Martin C Hartel1, Dongwook Lee2, Paul S Weiss3
1Department 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.
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.
