Page 66 - Read Online

Zhao et al. Soft Sci 2024;4:18 Soft Science
DOI: 10.20517/ss.2024.04

Review Article Open Access

Recent advances of sweat sampling, sensing,

energy-harvesting and data-display toward flexible
sweat electronics

1
1,#
1
1
Guangyao Zhao 1,# , Zhiyuan Li , Xingcan Huang , Qiang Zhang , Yiming Liu , Xinge Yu 1,2,*
1
Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China.
2
Hong Kong Center for Cerebro-Cardiovascular Health Engineering, Hong Kong 999077, China.
#
Authors contributed equally.
* Correspondence to: Prof. Xinge Yu, Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee
Avenue, Kowloon Tong, Hong Kong 999077, China. E-mail: xingeyu@cityu.edu.hk
How to cite this article: Zhao G, Li Z, Huang X, Zhang Q, Liu Y, Yu X. Recent advances of sweat sampling, sensing, energy-
harvesting and data-display toward flexible sweat electronics. Soft Sci 2024;4:18. https://dx.doi.org/10.20517/ss.2024.04
Received: 31 Jan 2024 First Decision: 27 Mar 2024 Revised: 9 Apr 2024 Accepted: 7 May 2024 Published: 20 May 2024

Academic Editors: Zhifeng Ren, Roozbeh Ghaffari Copy Editor: Pei-Yun Wang Production Editor: Pei-Yun Wang

Abstract
Sweat contains diverse types of biomarkers that can mirror an individual’s health condition. The forefront research
of sweat monitoring primarily focuses on sensing basic parameters, i.e., sweat rate and single electrolyte
imbalances in controlled laboratory settings. However, recent works show the potential of sweat for the rich
biomarkers in aspects of comprehensive health status display, timely safety alarming, and energy harvesting. The
advances in wearable flexible electronics enable continuous, real-time, noninvasive detection of multiple sweat
components, providing molecular-level insights into human physiology and psychology information; additionally,
the efficient sweat extraction technologies of flexible electronics promote its application in energy harvesting,
contributing to advancing a flexible sweat platform. This review comprehensively explores flexible sweat-based
electronics, encompassing four key aspects: sweat sampling methods, sweat-based sensors, sweat-based energy
harvesters, and sweat data display methods. Firstly, the traditional sweat-based platform is discussed in sweat
sampling, sensing, and data analysis. Then, the development of wearable sweat sampling methods is discussed
with a comparison of the traditional sweat collection methods. After that, the recent advances in sweat-based
biosensors for monitoring diverse sweat analytes, such as the perspiration volume, glucose, lactate, and uric acid
levels, are summarized. Subsequently, this review also highlights the recent progress and potential value of sweat-
based energy harvesters in sweat-activated batteries and bio-fuel cells. Furthermore, multiple data display
methods are proposed to achieve accurate feedback on health status, such as colorimetric techniques, light-
emitting diodes, actuators, etc. Finally, this review concludes the main current challenges faced in practical

© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0
International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, sharing,
adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as
long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and
indicate if changes were made.

www.oaepublish.com/ss