As a class of emerging multifunctional soft materials, gallium-based liquid metal (LM) amalgams, metal/nonmetal particles dispersed in an LM environment, suggest a combination of intriguing properties. In this article, Mg particles in gallium-indium alloy for making new conceptual biomedical materials, which can adapt to any irregular skin surface, are introduced, and superior photothermal effect with a 61.5% photothermal conversion (PTC) increase with respect to that of the LM is realized. The formation of a new intermetallic phase Mg Ga and adjustable surface roughness, which guarantees a rapid temperature increase when illuminated by laser, are found to be responsible for the photothermal effect enhancement. The obtained soft metallic mixtures also possess excellent thermal conductivity, favorable formability, together with benign biocompatibility. The potential use of the currently produced LM mixtures for conformable photothermal therapy (PTT) of skin tumors, which is hard to precisely heat otherwise via conventional ways, is explored. The soft Mg-GaIn mixtures can adapt to irregular tumor shapes to achieve conformable and minimal invasive tumor treatment. In vivo experiments on skin-tumor-bearing mice show obvious tumor growth suppression and life span extension after PTT treatment. As a novel functional PTC material, the Mg-GaIn mixtures exhibit promising potentials in the coming clinical cancer theranostics.

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Accurately mapping neuronal activity across brain networks is critical to understand behaviors, yet it is very challenging due to the need of tools with both high spatial and temporal resolutions. Here, penetrating arrays of flexible microelectrodes made of low‐impedance nanomeshes are presented, which are capable of recording single‐unit electrophysiological neuronal activity and at the same time, transparent, allowing to bridge electrical and optical brain mapping modalities. These 32 transparent penetrating electrodes with site area, 225 µm2, have a low impedance of ≈149 kΩ at 1 kHz, an adequate charge injection limit of ≈0.76 mC cm−2, and up to 100% yield. Mechanical bending tests reveal that the array is robust up to 1000 bending cycles, and its high transmittance of 67% at 550 nm makes it suitable for combining with various optical methods. A temporary stiffening using polyethylene glycol allows the penetrating nanomesh arrays to be inserted into the brain minimally invasively, with in vivo validation of recordings of spontaneous and evoked single‐unit activity of neurons across layers of the mouse visual cortex. Together, these results establish a novel neurotechnology—transparent, flexible, penetrating microelectrode arrays—which possesses great potential for brain research.

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A gas-mediated fabrication of centimeter-scale two-dimensional (2D) semiconductors and ultraviolet photodetector by a liquid metal-based printing was reported. Various large-scale 2D materials (Ga2O3, In2O3, SnO) were demonstrated to be directly printed at ambient air on different substrates. Such printing represents a generic, fast, clean, and scalable technique to quickly manufacture 2D semiconductors. The electrical properties were explored to quantify the printed 2D films, which were somewhat deficient in previous studies. In particular, to explore and facilitate the advantages of this 2D semiconductor in functional electronic applications, strategies for realizing fully printed Ga2O3/Si heterojunction photodetector via low-temperature and low-cost processes were developed. The device exhibits excellent sensibility and rapid photoresponse times. This work offers feasible way to develop high-performance ultraviolet photodetector for mass production. It also suggests a promising direction for making large-scale 2D photoelectronic and electronic systems and is expected to be extensively useful in the coming time.