A Non-Newtonian liquid metal enabled enhanced electrography.
A Non-Newtonian liquid metal enabled enhanced electrography.
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DOI：
10.1016/j.bios.2023.115414
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发表时间：
2023-05
影响因子：
12.6
通讯作者：
Veronika Timosina;Tim Cole;Hongda Lu;Jian Shu;Xiaoping Zhou;Chengchen Zhang;Jinhong Guo;Omid Kavehei;Shiyang Tang
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文献类型：
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作者：
Veronika Timosina;Tim Cole;Hongda Lu;Jian Shu;Xiaoping Zhou;Chengchen Zhang;Jinhong Guo;Omid Kavehei;Shiyang Tang
生物电位信号，如心电图（ECG）、肌电图（EMG）和脑电图（EEG），可以帮助诊断心脏病、肌肉骨骼和神经系统疾病。干银/氯化银（Ag/AgCl）电极通常用于获得这些信号。虽然可以在Ag/AgCl电极中添加导电水凝胶以改善电极与皮肤之间的接触和粘附性，但干燥的电极容易运动。考虑到导电水凝胶随着时间的推移而变干，这些电极的使用通常会在前端模拟电路中产生不平衡的皮肤电极阻抗和许多传感问题。这个问题可以扩展到其他几种常用的电极类型，特别是对于需要长期可穿戴监测的应用，如动态癫痫监测。液态金属合金，如共晶镓铟（EGaIn），可以满足稠度和可靠性方面的关键要求，但在低粘度和泄漏风险方面存在挑战。为了解决这些问题，在这里，我们展示了使用非共晶Ga-In合金作为剪切变薄的非牛顿流体，为商业水凝胶电极、干电极和传统液态金属的电测量提供卓越的性能。这种材料在静止时具有高粘度，在剪切时可以像液态金属一样流动，防止泄漏，同时允许有效地制造电极。此外，Ga-In合金不仅具有良好的生物相容性，而且还提供了出色的皮肤电极界面，允许长期获取高质量的生物信号。所提出的Ga-In合金是一种优越的替代传统电极材料，用于现实世界的电图或生物阻抗测量。
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.