silicon wafer, electronic skin, which is usually fabricated with mechanically compliant materials (low modulus, stretchable, and flexible) overcomes the fundamental mismatch between rigid devices and soft biological tissues. [13,14] At present, inorganic and organic electronic materials integrated with elastomeric substrates are the two popular approaches to fabricate electronic skin. Nonstretchable inorganic electronic materials, such as gold, copper, and silver, change the geometric structure to fit the stretched substrates. [15][16][17][18] It is obvious that the complicated, expensive fabrication methods, and limited stretchability of inorganic electronic materials restrict their widespread application. Alternatively, other inorganic electronic materials, such as nanoparticles [19][20][21] and carbon nanotubes, [22][23][24] are deposited on elastomer substrates to form a thin nanopath that can be extended when the substrates are stretched. With low-cost fabrication methods, such as direct printing [20,25] and transfer printing, [21] these materials have been highly successfully used to fabricate stretchable circuits, [26] sensing arrays, [27] and near field communication antennae. [21] Meanwhile, organic electronic materials, such as conductive small molecules and polymers and carbon-based conductive materials, [28] have good stretchability and their special chemical groups provide good conductivity. [29][30][31] However, the conductivities of nanoparticle layers and organic electronic materials are far lower than those of metal conductors. Thus, it is of great importance to develop new materials with both excellent conductivity and stretchability. Most electronic skin is fabricated on a flat device and subsequently transferred to skin. We suggest that the new conductive materials be directly printed onto the skin using a low-cost preparation method and be super-compliant and customizable.Liquid metal (eutectic gallium-indium, EGaIn) is an attractive conductive material that has shown significant promise for broad applications in flexible electronics. With its high electrical conductivity (EGaIn: 3.4 × 10 6 S m −1 ) [32] and excellent fluidity, [33] liquid metal has attracted great interest in many applications, such as stretchable antennae, [34,35] bioelectrodes, [36] strain sensors, [37] pressure sensors, [38] loudspeakers, [39] and soft robots. [40] Additionally, gallium is nontoxic with low vapor pressure, [41] which can be useful in an ambient environment. [42] Meanwhile, various patterning techniques of liquid metal have also been developed, such as microchannel injection, [43] atomized Because of its seamless skin interface, electronic skin has attracted increasing attention in the field of biomedical sensors and medical devices. Most electronic skins are based on organic or inorganic electronic materials. However, the low flexibility of inorganic materials and the limited conductivity of organic materials restricts their widespread use. A new approach is reported to fabricate electronic tattoos from N...

With inherent flexibility, high electroconductivity, excellent thermal conductivity, easy printability and biosafety, gallium-based functional liquid metals (LMs) have been increasingly evaluated for biomedical applications, especially as electronic skin (e-skin). Extending these versatile materials to more challenging applications is a worthwhile pursuit. To realize precise and spatiotemporal multisite tumor treatment under an alternating magnetic field (AMF), an oxidized GaIn (O-GaIn) mixture-based e-skin is developed and demonstrated to be printable. Compared with the commonly utilized nonoxidized GaIn, O-GaIn possesses outstanding adhesion to the skin surface and can be directly and quickly printed into various customized patterns.The LM e-skin thus constructed as conformable bioelectrodes on tumorbearing mice exhibits evident feasibility for administrating non-invasive wireless multisite tumor therapy under AMF exposure due to its favorable magnetothermal effects. These in vivo experiments reveal remarkable tumor growth inhibition and increased life span in mice, especially in the case of multilesion treatment. A favorable biomedical strategy based on O-GaIn material for developing future non-invasive and high-performance cancer therapy, which is also promising for treating whole-body diseases in the future, is provided.while O-GaIn displayed an uneven cut surface with air holes inside (Figure 1b-II,-III). In addition, SEM images revealed that GaIn had a glossy surface, while an obvious rough oxide layer appeared on the surface of O-GaIn-30 and many metal oxide particles arose on the surface of O-GaIn-60 (insets of Figure 1c-e). These SEM images illustrated that different stirring time

Stretchable conductive fibers have gained significant attention in the field of wearable and flexible electronics because of their inherited unique properties. Up to now, there are few reports regarding the highly stretchable fibers with excellent electronic properties. In this work, a highly stretchable fiber with superior electrical conductivity is fabricated, which contains a core fiber, an intermediate modified layer, and an outer eutectic–gallium–indium liquid metal layer. The fiber demonstrates an excellent electrical conductivity of over 103 S cm–1 when stretched up to 500% strain, which is far superior to the existing stretchable conductive fiber. The stretchable conductive fiber shows excellent thermostability with a maximum operating temperature of nearly 250 °C. Such unique fibers can be applied as highly stretchable, deformable conductor to charge a mobile phone, and sensor to monitor human activities. This work offers promising application in the areas of flexible and wearable electronics.

Scheme 1. Schematic illustration of the LM/CA hydrogel preparation and endovascular embolization process. www.advancedsciencenews.com

Electronic skin (e-skin) is attracting huge attention due to its promising applications in diverse fields, including biomimetic machines, artificial intelligence and smart robotics.