Direct Wiring of Liquid Metal on an Ultrasoft Substrate Using a Polyvinyl Alcohol Lift-off Method
Direct Wiring of Liquid Metal on an Ultrasoft Substrate Using a Polyvinyl Alcohol Lift-off Method
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DOI：
10.1021/acsami.1c20628
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发表时间：
2022-01-27
影响因子：
9.5
通讯作者：
Ota, Hiroki
中科院分区：
文献类型：
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作者：
Murakami, Koki;Tochinai, Ryota;Ota, Hiroki
近年来，在先进的可穿戴设备、可植入设备和软机器人中，提出了基于生物组织和水凝胶等超软材料的布线和系统构建。在软导电材料中，镓基液态金属(LMS)既具有生物相容性，又具有超软性能，使其成为超软衬底电极的理想匹配材料。然而，凝胶和组织比传统的软基质，如Ecoflex和聚二甲基硅氧烷更柔软，对LMS的润湿性更差。在这项研究中，我们展示了利用牺牲的聚乙烯醇(PVA)薄膜将由Ga基LM和Ni纳米颗粒组成的LM糊状物转移到生物组织和凝胶等超光滑基质上。制备在PVA膜上的LM浆料图案沿表面不规则性附着在超光滑的衬底上，在PVA溶解于水中之前未被PVA膜破坏而转移。可以布线的最小线宽约为165微米。也可以进行三维布线，例如凝胶纤维表面的螺旋结构。将这种转移方法应用于使用LM糊状导线的组织，成功地刺激了大鼠的迷走神经。此外，我们还成功地将在PVA薄膜上构建的温度测量系统转移到凝胶上。固态电子元件和LM浆料之间的连接稳定，并保持了温度传感系统的功能。这种对布线制造和系统集成的基础研究将有助于基于超软基板的先进电子设备的发展。
In recent years, wiring and system construction on ultrasoft materials such as biological tissues and hydrogels have been proposed for advanced wearable devices, implantable devices, and soft robotics. Among the soft conductive materials, Ga-based liquid metals (LMs) are both biocompatible and ultrasoft, making them a good match for electrodes on the ultrasoft substrates. However, gels and tissues are softer and less wettable to the LMs than conventional soft substrates such as Ecoflex and polydimethylsiloxane. In this study, we demonstrated the transfer of LM paste composed of Ga-based LM and Ni nanoparticles onto ultrasoft substrates such as biological tissue and gels using sacrificial polyvinyl alcohol (PVA) films. The LM paste pattern fabricated on the PVA film adhered to the ultrasoft substrate along surface irregularities and was transferred without being destroyed by the PVA film before the PVA's dissolution in water. The minimum line width that could be wired was approximately 165 mu m. Three-dimensional wiring, such as the helical structure on the gel fiber surface, is also possible. Application of this transfer method to tissues using LM paste wiring allowed the successful stimulation of the vagus nerve in rats. In addition, we succeeded in transferring a temperature measurement system fabricated on a PVA film onto the gel. The connection between the solid-state electrical element and the LM paste was stable and maintained the functionality of the temperature-sensing system. This fundamental study of wiring fabrication and system integration can contribute to the development of advanced electric devices based on ultrasoft substrates.