Underwater surface electromyography (UW-sEMG) acquisition with long-term high quality is crucial to underwater activities, including rehabilitation, fatigue measurement, and sports monitoring. However, most UW-sEMG electrodes suffer significant performance decline, especially for hydrogel electrodes, due to the swelling-induced mechanical, electrical, and adhesive degradation. Maintaining high performance underwater over extended periods is challenging. The controlled underwater adhesion-detachment behavior of starfish is inspirative. Here, a starfish tube feet-inspired hydrogel (STFH) electrode is developed for UW-sEMG recording, including a micro-swelling hydrogel pillar, a biomimetic silicone sucker, and an Ag/AgCl disc electrode. By soaking freeze-dried hydrophilic hydrogel in tannic acid (TA) solution, the hydrogel exhibits skin-like modulus of 22.4 kPa, low skin impedance of 18.3 kΩ (10 Hz) and low equilibrium swelling ratio. Unlike traditional strategies for improving anti-swelling properties, this work leverages the interaction between the sucker and the swollen hydrogel to promote conformal contact. Consequently, the sEMG signal exhibits SNR of 26.7 dB and baseline noise of 12.8 μV even after 60 min of underwater working. The STFH electrode also shows anti-noise capability to resist skin vibration and wave oscillation. This STFH electrode enables durable UW-sEMG acquisition, which could further extend from the arm to the wrist to adapt wearing habits.

中文翻译：

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受海星管脚启发的水凝胶电极，可实现持久的水下表面肌电采集


长期高质量的水下表面肌电图（UW-sEMG）采集对于水下活动（包括康复、疲劳测量和运动监测）至关重要。然而，由于膨胀引起的机械、电气和粘合剂降解，大多数 UW-sEMG 电极的性能显着下降，尤其是水凝胶电极。在水下长时间保持高性能具有挑战性。海星受控的水下粘附-脱离行为具有启发性。在这里，开发了一种用于 UW-sEMG 记录的海星管脚水凝胶 (STFH) 电极，包括微膨胀水凝胶柱、仿生硅胶吸盘和 Ag/AgCl 盘电极。将冻干亲水水凝胶浸泡在单宁酸（TA）溶液中，水凝胶表现出22.4 kPa的类皮模量、18.3 kΩ（10 Hz）的低皮肤阻抗和低平衡溶胀比。与提高抗膨胀特性的传统策略不同，这项工作利用吸盘和膨胀水凝胶之间的相互作用来促进保形接触。因此，即使在水下工作 60 分钟后，sEMG 信号仍表现出 26.7 dB 的信噪比和 12.8 μV 的基线噪声。 STFH电极还表现出抗噪声能力，可以抵抗皮肤振动和电波振荡。这种 STFH 电极可实现持久的 UW-sEMG 采集，可以进一步从手臂延伸到手腕以适应佩戴习惯。