Liquid metal electrodes micro-array for electrical stimulation via direct contact

David, Romain; Miki, Norihisa

doi:10.1109/memsys.2018.8346565

Cited by 3 publications

(5 citation statements)

References 9 publications

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“…The transfer method in this study has the distinct feature in that the substrate eventually melts and disappears, which makes it more flexible. Another study used LM to fabricate electrode arrays to electrically stimulate biological tissue at the tissue-contacting surface . The LM paste electrodes fabricated in this study are easier to connect and more flexible because they adhere to the biological tissue to make contact.…”

Section: Resultsmentioning

confidence: 99%

“…Another study used LM to fabricate electrode arrays to electrically stimulate biological tissue at the tissue-contacting surface. 35 The LM paste electrodes fabricated in this study are easier to connect and more flexible because they adhere to the biological tissue to make contact. The adhesiveness of the LM paste can be considered to be sufficient because vagus nerve stimulation was achieved.…”

Section: Vagus Nerve Direct Stimulationmentioning

confidence: 97%

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Direct Wiring of Liquid Metal on an Ultrasoft Substrate Using a Polyvinyl Alcohol Lift-off Method

Murakami

Tochinai

Tachibana

et al. 2022

ACS Appl. Mater. Interfaces

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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 μm. 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.

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Section: Resultsmentioning

confidence: 99%

Section: Vagus Nerve Direct Stimulationmentioning

confidence: 97%

Direct Wiring of Liquid Metal on an Ultrasoft Substrate Using a Polyvinyl Alcohol Lift-off Method

Murakami

Tochinai

Tachibana

et al. 2022

ACS Appl. Mater. Interfaces

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“…We investigated the usability of the shell created via galvanic replacement onto liquid metal electrodes. We used in this study the flexible chip with liquid metal microelectrode arrays we previously developed . The base system used in these experiments is a polydimethylsiloxane (PDMS) chip of 1 cm by 1 cm presenting an array of four open microchannels of 200 by 200 μm rectangular cross section (Figure A).…”

Section: Resultsmentioning

confidence: 99%

“…We used in this study the flexible chip with liquid metal microelectrode arrays we previously developed. 35 The base system used in these experiments is a polydimethylsiloxane (PDMS) chip of 1 cm by 1 cm presenting an array of four open microchannels of 200 by 200 μm rectangular cross section (Figure 12A). The microchannels were filled with the same liquid metal used for the droplets.…”

Section: ■ Resultsmentioning

confidence: 99%

Tunable Noble Metal Thin Films on Ga Alloys via Galvanic Replacement

David

Miki

2018

Langmuir

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Room-temperature liquid metals such as GaInSn or EGaIn present the most attractive properties for soft and highly stretchable electronics. Recently, several methods have been investigated to functionalize the surface of the liquid metal via coatings and encapsulation. However, most can hardly be extended to other samples than droplets. In this study, we focus on the tunability of the process of galvanic replacement of Ga alloys with gold to form thin-film encapsulation. We characterized in-depth the obtainable composition and structure of a noble metal shell formed on the liquid metal via scanning electron microscopy, energy-dispersive X-ray, and topographic laser microscopy and highlighted the change in mechanism of galvanic replacement in different pH ranges. We showed the tunability of the surface morphology selection of different pH ranges, the solutions concentrations, and the reaction time. The adjustment of the pH of KAuBr solution to the preferential GaO-free domain led to the successful formation of a sub-micrometer thin uniform coating with more than 60% of Au and reduced level of oxygen from 30% down to 10%. We finally demonstrated the effect of the coating composition on the electrical properties of the liquid metal using a simple and fast phase-drop measurement setup on the droplet and microchannels. A high correlation between the amount of noble metal deposited and the electrical properties of the droplets was demonstrated.

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“…Flexible electrodes prepared from LM have good compliance to alleviate mechanical mismatch at the tissue–electrode interface, which plays a key role in long-term implantation stability. In 2018, R. David et al [ 12 ] developed an LM electrode microarray that allows direct electrical stimulation of biological tissues, and in vitro experiments were performed to record the frequency behavior of electrode coupling over the 1 Hz–1 MHz frequency band with input amplitude between 250 mV and 2 V. The first effort to introduce gallium-based LM components into the field of implantable electrical stimulation systems was demonstrated. The following year, Li et al [ 13 ] prepared gallium-indium-tin LM-based electrodes encapsulated in a soft PDMS, and formed IDE capacitors.…”

Section: Introductionmentioning

confidence: 99%

Liquid Metal-Based Flexible Bioelectrodes for Management of In-Stent-Restenosis: Potential Application

Zhang

Deng

2023

Biosensors

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Although vascular stents have been widely used in clinical practice, there is still a risk of in-stent restenosis after their implantation. Combining conventional vascular stents with liquid metal-based electrodes with impedance detection, irreversible electroporation, and blood pressure detection provides a new direction to completely solve the restenosis problem. Compared with conventional rigid electrodes, liquid metal-based electrodes combine high conductivity and stretchability, and are more compliant with the implantation process of vascular stents and remain in the vasculature for a long period of time. This perspective reviews the types and development of conventional vascular stents and proposes a novel stent that integrates liquid metal-based electrodes on conventional vascular stents. This vascular stent has three major functions of prediction, detection and treatment, and is expected to be a new generation of cardiovascular implant with intelligent sensing and real-time monitoring.

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Liquid metal electrodes micro-array for electrical stimulation via direct contact

Cited by 3 publications

References 9 publications

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

Tunable Noble Metal Thin Films on Ga Alloys via Galvanic Replacement

Liquid Metal-Based Flexible Bioelectrodes for Management of In-Stent-Restenosis: Potential Application

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