A non-Newtonian liquid metal enabled enhanced electrography
A non-Newtonian liquid metal enabled enhanced electrography
Biopotential signals, like electrocardiography (ECG), electromyography (EMG), and electroencephalography (EEG), can help diagnose cardiological, musculoskeletal and neurological disorders. Dry silver/silver chloride (Ag/AgCl) electrodes are commonly used to obtain these signals. While a conductive hydrogel can be added to Ag/AgCl electrodes to improve the contact and adhesion between the electrode and the skin, dry electrodes are prone to movement. Considering that the conductive hydrogel dries over time, the use of these electrodes often creates an imbalanced skin-electrode impedance and a number of sensing issues in the front-end analogue circuit. This issue can be extended to several other electrode types that are commonly in use, in particular, for applications with a need for long-term wearable monitoring such as ambulatory epilepsy monitoring. Liquid metal alloys, such as eutectic gallium indium (EGaIn), can address key critical requirements around consistency and reliability but present challenges on low viscosity and the risk of leakage. To solve these problems, here, we demonstrate the use of a non-eutectic Ga–In alloy as a shear-thinning non-Newtonian fluid to offer superior performance to commercial hydrogel electrodes, dry electrodes, and conventional liquid metals for electrography measurements. This material has high viscosity when still and can flow like a liquid metal when sheared, preventing leakage while allowing the effective fabrication of electrodes. Moreover, the Ga–In alloy not only has good biocompatibility but also offers an outstanding skin-electrode interface, allowing for the long-term acquisition of high-quality biosignals. The presented Ga–In alloy is a superior alternative to conventional electrode materials for real-world electrography or bioimpedance measurement.
Reproducibility of Results, Biosensing Techniques, Electrodes, Electric Impedance, Alloys, Indium, Electrocardiography, Hydrogels
Timosina, Veronika
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Cole, Tim
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Lu, Hongda
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Shu, Jian
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Zhou, Xiangbo
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Zhang, Chengchen
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Guo, Jinhong
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Kavehei, Omid
eb64ae5e-025f-4bbf-89b2-8ca6fa1af744
Tang, Shi Yang
1d0f15c6-2a3e-4bad-a3d8-fc267db93ed4
1 September 2023
Timosina, Veronika
3bcabfcf-fcec-4932-aa55-81ef6aa12360
Cole, Tim
78cebdf5-e360-4e8e-9dea-ba4b88306980
Lu, Hongda
731b3c09-82ae-408b-8218-95b0de29f2dd
Shu, Jian
10c82f94-8f99-4785-b33f-fa20484344fd
Zhou, Xiangbo
fad0d425-1021-4ce3-8dbd-cf88a03a8a7c
Zhang, Chengchen
abc47c06-4b99-4aed-be72-463f211e9dfa
Guo, Jinhong
d65d7044-32c8-4028-a6b3-d221ad8bf006
Kavehei, Omid
eb64ae5e-025f-4bbf-89b2-8ca6fa1af744
Tang, Shi Yang
1d0f15c6-2a3e-4bad-a3d8-fc267db93ed4
Timosina, Veronika, Cole, Tim, Lu, Hongda, Shu, Jian, Zhou, Xiangbo, Zhang, Chengchen, Guo, Jinhong, Kavehei, Omid and Tang, Shi Yang
(2023)
A non-Newtonian liquid metal enabled enhanced electrography.
Biosensors and Bioelectronics, 235, [115414].
(doi:10.1016/j.bios.2023.115414).
Abstract
Biopotential signals, like electrocardiography (ECG), electromyography (EMG), and electroencephalography (EEG), can help diagnose cardiological, musculoskeletal and neurological disorders. Dry silver/silver chloride (Ag/AgCl) electrodes are commonly used to obtain these signals. While a conductive hydrogel can be added to Ag/AgCl electrodes to improve the contact and adhesion between the electrode and the skin, dry electrodes are prone to movement. Considering that the conductive hydrogel dries over time, the use of these electrodes often creates an imbalanced skin-electrode impedance and a number of sensing issues in the front-end analogue circuit. This issue can be extended to several other electrode types that are commonly in use, in particular, for applications with a need for long-term wearable monitoring such as ambulatory epilepsy monitoring. Liquid metal alloys, such as eutectic gallium indium (EGaIn), can address key critical requirements around consistency and reliability but present challenges on low viscosity and the risk of leakage. To solve these problems, here, we demonstrate the use of a non-eutectic Ga–In alloy as a shear-thinning non-Newtonian fluid to offer superior performance to commercial hydrogel electrodes, dry electrodes, and conventional liquid metals for electrography measurements. This material has high viscosity when still and can flow like a liquid metal when sheared, preventing leakage while allowing the effective fabrication of electrodes. Moreover, the Ga–In alloy not only has good biocompatibility but also offers an outstanding skin-electrode interface, allowing for the long-term acquisition of high-quality biosignals. The presented Ga–In alloy is a superior alternative to conventional electrode materials for real-world electrography or bioimpedance measurement.
Text
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Accepted/In Press date: 19 May 2023
Published date: 1 September 2023
Additional Information:
Funding Information:
This work was funded by Engineering and Physical Sciences Research Council (EPSRC) grant EP/V008382/1 and the Australian Research Council Discovery Project grant DP230100019 .
Publisher Copyright:
© 2023 The Authors
Keywords:
Reproducibility of Results, Biosensing Techniques, Electrodes, Electric Impedance, Alloys, Indium, Electrocardiography, Hydrogels
Identifiers
Local EPrints ID: 481929
URI: http://eprints.soton.ac.uk/id/eprint/481929
ISSN: 0956-5663
PURE UUID: 9156a84f-1c73-4cfe-b3aa-ab9d0d6336a5
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Date deposited: 13 Sep 2023 17:10
Last modified: 18 Mar 2024 04:15
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Contributors
Author:
Veronika Timosina
Author:
Tim Cole
Author:
Hongda Lu
Author:
Jian Shu
Author:
Xiangbo Zhou
Author:
Chengchen Zhang
Author:
Jinhong Guo
Author:
Omid Kavehei
Author:
Shi Yang Tang
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