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Ma et al. Soft Sci 2024;4:8 Soft Science
DOI: 10.20517/ss.2023.41

Research Article Open Access

A dual-mode wearable sensor with coupled ion and

pressure sensing

#
Biao Ma # , Ke Huang # , Gangsheng Chen , Yingnan Tian, Nan Jiang, Chao Zhao, Hong Liu *
State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University,
Sipailou 2#, Nanjing 210096, Jiangsu, China.
#
Authors contributed equally.
* Correspondence to: Prof. Hong Liu, State Key Laboratory of Digital Medical Engineering, School of Biological Science and
Medical Engineering, Southeast University, Sipailou 2#, Nanjing 210096, Jiangsu, China. E-mail: liuh@seu.edu.cn
How to cite this article: Ma B, Huang K, Chen G, Tian Y, Jiang N, Zhao C, Liu H. A dual-mode wearable sensor with coupled ion
and pressure sensing. Soft Sci 2024;4:8. https://dx.doi.org/10.20517/ss.2023.41
Received: 31 Aug 2023 First Decision: 7 Oct 2023 Revised: 7 Nov 2023 Accepted: 23 Nov 2023 Published: 16 Jan 2024

Academic Editor: Zhifeng Ren Copy Editor: Dong-Li Li Production Editor: Dong-Li Li

Abstract
Simultaneous monitoring of the body’s biochemical and biophysical signals via wearable devices can provide a
comprehensive assessment of an individual’s health state. However, current multifunctional sensors for
synchronous biochemical and biophysical sensing rely on discrete sensing units, posing a limitation in increased
complexity in device assembly, signal processing, and system integration. In this study, we report a dual-mode and
self-powered wearable sensor with ion and pressure-sensing capabilities by interfacing a hydrogel film with a solid
ion-selective electrode. The hydrogel film can not only collect natural sweat from the skin but also offer a
piezoionic response to pressure. We show that wrist pulse-induced pressure response can be incorporated into the
noise of the response to sweat sodium ions, allowing for the simultaneous measurement of heart rate and sweat
electrolytes. This work provides an example of simplifying the development of wearable multimode sensors
through the rational design of classic electrochemical sensors.

Keywords: Wearable sweat sensor, ion selective electrode, piezoionic response, hydrogel

INTRODUCTION
Skin-mounted wearable sensors are integrated analytical devices that can monitor various physiological
signals in a real-time and continuous way . Their point of care feature, along with non-invasive or
[1-5]
minimally invasive operations, provides a promising pathway to user-friendly healthcare and

© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0
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