Liquid Metal Enabled Flexible Electronics, Soft Machines and Biosensors

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• When I first touched the gallium-based liquid metal in 2018, I was deeply attracted by such a fascinating soft matter due to its combined advantages of fluidity, metallic conductivity, low toxicity, and low viscosity. Then I wanted to do something with it. The first successful try after many failures is magnetic printing of liquid metal. I added magnetic microparticles to the liquid metal, followed by using a magnet to spread the liquid metal over the substrate surface. In such a simple way, liquid metal can be directly printed on various surfaces, without any pretreatment of substrates or granulation of liquid metal. This method avoids many issues arising from the high surface tension since the liquid metal was passively attached to the substrate under the magnetic field. We continuously explore the power of magnetic printing by creating metal-gel bioelectronic devices, and surface-embedded liquid metal electrodes with abrasion resistance.
• I also realized that liquid metal cannot just be used as a stretchable circuit. Multifunctionality is unique for liquid metals, which may reshape the way to create functional devices. I tried to couple the resistive sensing and electrothermal capabilities of liquid metal to create a soft actuator that can autonomously respond to mechanical stimuli like a Venus flytrap. This may inspire the design of bioinspired soft machines with embodied intelligence (e.g. without complicated electronics).
• I am also interested in merging liquid metal into biosensors for point-of-care testing. By using liquid metal as a responsive fluidic valve or a molecular capsule, various diagnostic devices can be operated in an on-demand manner.

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