The actuation of micro/nanomachines by means of a magnetic field is a promising fuel-free way to transport cargo in microscale dimensions. This type of movement has been extensively studied for a variety of micro/nanomachine designs, and a special magnetic field configuration results in a near-surface walking. We developed “walking” micromachines which transversally move in a magnetic field, and we used them as microrobotic scalpels to enter and exit an individual cancer cell and cut a small cellular fragment. In these microscalpels, the center of mass lies approximately in the middle of their length. The microrobotic scalpels show good propulsion efficiency and high step-out frequencies of the magnetic field. Au/Ag/Ni microrobotic scalpels controlled by a transversal rotating magnetic field can enter the cytoplasm of cancer cells and also are able to remove a piece of the cytosol while leaving the cytoplasmic membrane intact in a microsurgery-like manner. We believe that this concept can be further developed for potential biological or medical applications.

Succeeding graphene, monoelemental two-dimensional (2D) materials such as germanene and silicene, coined as "Xenes", have attracted vast scientific and technological interests. Adding covalently bonded hydrogen on both sides of germanene leads to germanane (i.e., hydrogen-terminated germanene, GeH). Further, the covalent functionalization of germanane allows the tuning of its physical and chemical properties. Diverse variants of germananes have been synthesized, but current research is primarily focused on their fundamental properties. As a case in point, their applications as photo-and electrocatalysts in the field of modern energy conversion have not been explored. Here, we prepare 2D germanene-based materials, specifically germanane and germananes functionalized by various alkyl chains with different terminal groupsgermanane with methyl, propyl, hydroxypropyl, and 2-(methoxycarbonyl)ethyland investigate their structural, morphological, optical, electronic, and electrochemical properties. The bond geometries of the functionalized structures, their formation energies, and band gap values are investigated by density functional theory calculations. The functionalized germananes are tested as photoelectrocatalysts in the hydrogen evolution reaction (HER) and photo-oxidation of water. The performance of the germananes is influenced by the functionalized groups, where the germanane with −CH 2 CH 2 CH 2 OH termination records the lowest HER overpotentials and with −H termination reaches the highest photocurrent densities for water oxidation over the entire visible spectral region. These positive findings serve as an overview of organic functionalization of 2D germananes that can be expanded to other "Xanes" for targeted tuning of the optical and electronic properties for photo-and electrochemical energy conversion applications.

Research on wearable sensing technologies has been gaining considerable attention in the development of portable bio-monitoring devices for personal health. However, traditional energy storage systems with defined size and shape have inherent limitations in satisfying the performance requirements for flexible electronics. To overcome this constraint, three different configurations of flexible asymmetric supercapacitor (FASC) are fabricated on polyester/cellulose blend (PCB) cloth substrate using Ti 3 C 2 nanosheet (NS) and 1T WS 2 NS as electrodes, and aqueous pluronic gel as an electrolyte. Benefiting from the 2D material electrodes, the interdigitated FASC configuration exhibits excellent performance, flexibility, cyclic stability, wearability and can be configured into multiple units and shapes, which far exceed that exhibited by the textile-based FASC. Furthermore, the arbitrary ("AFN") and sandwich ("FLOWER") configurations Ti 3 C 2 NS/1T WS 2 NS FASC can be assembled directly on a PCB cloth substrate, thereby offering good structural integrity coupled with ease of assembly into integrated circuits of different shapes. More specifically, a lightweight, flexible, and wearable bio-monitoring system is developed by integrating force sensing device with interdigitated FASC, which can be used to monitor the physical status of human body during various activities. A potential application of this system in healthcare is successfully demonstrated and discussed.

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Yeasts play a key role in the production of alcoholic beverages by fermentation processes. However, because of their continuous growth, they commonly cause spoilage of the final product. Herein, we introduce dual magnetic/light‐responsive self‐propelled microrobots that can actively move in a beer sample and capture yeast cells. The presence of magnetic nanoparticles on the surface of the microrobots enables their magnetic actuation under fuel‐free conditions. In addition, their photoactivity under visible‐light irradiation leads to an overall enhancement of their swimming and yeast removal capabilities. It was found that after the application of the microrobots into a real unfiltered beer sample, these micromachines were able to remove almost 100 % of residual yeasts. In addition, these microrobots could also be added at the initial step of the fermentation process without altering the final beer properties, such as alcohol level, color, and pH. This work demonstrates the potential of using externally actuated microrobots as an innovative and low‐cost solution for avoiding yeast spoilage in complex liquid environments, such as alcoholic beverages. Therefore, these autonomous self‐propelled microrobots open new avenues for future applications in the food industry.

MXene‐based materials play an important role in the field of energy storage devices, owing to their layered structure with gravimetric/volumetric capacitances higher than that of graphene. However, owing to their tendency to bond to hydrogen or due to van der Walls forces, their performance is often reduced by the restacking of layers and subsequent reduction of their active surface area. In this work, we investigate the charge storage capacitance enhancement after inserting 1T‐phase WS2 nanospacers into the matrix of MXene Ti3C2 through a simple sonication‐assisted procedure, forming a 2D stack structure. We demonstrated that each exfoliation step enhances the capacitive behavior when compared to the starting MAX phase (Ti3AlC2). This new sandwich material shall have profound influence on the construction of 2D materials‐based supercapacitors.

The coronavirus disease 2019 (COVID‐19) has prompted an urgent demand for nanotechnological solutions towards the global healthcare crisis, particularly in the field of diagnostics, vaccines, and therapeutics. As an emerging tool for nanoscience and technology, micro/nanorobots have demonstrated advanced performances, such as self-propelling, precise maneuverability, and remote actuation, thus hold great potential to provide breakthroughs in the COVID-19 pandemic. Here we show a plasmonic-magnetic nanorobot-based simple and efficient COVID-19 detection assay through an electronic readout signal. The nanorobots consist of Fe 3 O 4 backbone and the outer surface of Ag, that rationally designed to perform magnetic-powered propulsion and navigation, concomitantly the probe nucleic acids transport and release upon the hybridization which can be quantified with the differential pulse voltammetry (DPV) technique. The magnetically actuated nanorobots swarming enables enhanced micromixing and active targeting, thereby promoting binding kinetics. Experimental results verified the enhanced sensing efficiency, with nanomolar detection limit and high selectivity. Further testing with extracted SARS-CoV-2 viral RNA samples validated the clinical applicability of the proposed assay. This strategy is versatile to extend targeting various nucleic acids, thus it could be a promising detection tool for other emerging infectious diseases, environmental toxins, and forensic analytes.

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