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Xiao et al. Soft Sci. 2025, 5, 40 Soft Science
DOI: 10.20517/ss.2025.51

Perspective Open Access

Engineering hydrogel-based conformal epidermal

electrodes for human-machine interaction

2
5,*
1
4,*
1,3
Mingxuan Xiao , Xin Zhang , Yibing Luo , Ruijie Xie , Kai Tao , Jin Wu 1,3,6,*
1
State Key Laboratory of Optoelectronic Materials and Technologies and the Guangdong Province Key Laboratory of Display
Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275,
Guangdong, China.
2
Fujian Key Laboratory of Special Intelligent Equipment Safety Measurement and Control, Fujian Special Equipment Inspection
and Research Institute, Fuzhou 350008, Fujian, China.
3
State Key Laboratory of Transducer Technology, Shanghai 200050, China.
4
Institute of Flexible Electronics (IFE, Future Technologies), Xiang’an Campus, Xiamen University, Xiamen 361102, Fujian, China.
5
The Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace, School of Mechanical Engineering,
Northwestern Polytechnical University, Xi’an 710072, Shaanxi, China.
6
State Key Laboratory of Intelligent Manufacturing Equipment and Technology, Wuhan 430074, Hubei, China.
* Correspondence to: Prof. Jin Wu, State Key Laboratory of Optoelectronic Materials and Technologies and the Guangdong
Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen
University, Xingang Xi Road, Guangzhou 510275, Guangdong, China. E-mail: wujin8@mail.sysu.edu.cn; Prof. Ruijie Xie, Institute
of Flexible Electronics (IFE, Future Technologies), Xiang’an Campus, Xiamen University, Xiang’an South Road, Xiamen 361102,
Fujian, China. E-mail: iferjxie@xmu.edu.cn; Prof. Kai Tao, The Ministry of Education Key Laboratory of Micro and Nano Systems
for Aerospace, School of Mechanical Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072,
Shaanxi, China. E-mail: taokai@nwpu.edu.cn
How to cite this article: Xiao, M.; Zhang, X.; Luo, Y.; Xie, R.; Tao, K.; Wu, J. Engineering hydrogel-based conformal epidermal
electrodes for human-machine interaction. Soft Sci. 2025, 5, 40. https://dx.doi.org/10.20517/ss.2025.51
Received: 12 Jul 2025 First Decision: 21 Jul 2025 Revised: 27 Jul 2025 Accepted: 7 Aug 2025 Published: 22 Aug 2025

Academic Editor: Yong-An Huang Copy Editor: Xing-Yue Zhang Production Editor: Xing-Yue Zhang

Abstract
Hydrogels, with their skin-like physicochemical properties, offer great potential as flexible electrodes for
electrophysiological interfaces and high-quality biosignal acquisition in human-machine interaction systems.
However, traditional hydrogel electrodes often face issues such as mechanical mismatch with skin, low electrical
conductivity, and poor adhesion, which hinder stable biosignal acquisition with high signal-to-noise ratio. To
address these challenges, optimizing conductivity, compliance, and adhesion is crucial. This perspective reviews
recent advancements in hydrogel electrode optimization, materials design, interface engineering, human-machine
interaction applications, and future directions for hydrogel-based biointerfaces.

Keywords: Flexible hydrogel electrodes, human-machine interaction, flexible and wearable epidermal sensor,
hydrogel sensor

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