Fuel‐Free Synthetic Micro‐/Nanomachines

Inspired by the swimming of natural microorganisms, synthetic micro‐/nanomachines, which convert energy into movement, are able to mimic the function of these amazing natural systems and help humanity by completing environmental and biological tasks. While offering autonomous propulsion, conventional micro‐/nanomachines usually rely on the decomposition of external chemical fuels (e.g., H₂O₂), which greatly hinders their applications in biologically relevant media. Recent developments have resulted in various micro‐/nanomotors that can be powered by biocompatible fuels. Fuel‐free synthetic micro‐/nanomotors, which can move without external chemical fuels, represent another attractive solution for practical applications owing to their biocompatibility and sustainability. Here, recent developments on fuel‐free micro‐/nanomotors (powered by various external stimuli such as light, magnetic, electric, or ultrasonic fields) are summarized, ranging from fabrication to propulsion mechanisms. The applications of these fuel‐free micro‐/nanomotors are also discussed, including nanopatterning, targeted drug/gene delivery, cell manipulation, and precision nanosurgery. With continuous innovation, future autonomous, intelligent and multifunctional fuel‐free micro‐/nanomachines are expected to have a profound impact upon diverse biomedical applications, providing unlimited opportunities beyond one's imagination.     

Pistachio‐Shuck‐Like MoSe2/C Core/Shell Nanostructures for High‐Performance Potassium‐Ion Storage

Potassium‐ion batteries (KIBs) have recently attracted intensive attention because of the abundant potassium resources and their low cost and high safety. However, the major challenge faced by KIBs lies in the lack of stable and high‐capacity materials for the intercalation/deintercalation of large‐size potassium ions. A unique pistachio‐shuck‐like MoSe₂/C core/shell nanostructure (PMC) is synthesized herein as an advanced anode for boosting the performance of KIBs. This PMC is featured with a few layers of molybdenum selenide as the core with an expanded interlayer spacing of ≈0.85 nm, facilitating the intercalation/deintercalation of K ions, and a thin amorphous carbon as the shell, which can confine the active molybdenum selenide nanosheets during cycling for maintaining the high structural stability. Most importantly, as a whole, the PMC has the advantages of reducing the surplus hollow interior space for improving its packing density and buffering the volume expansion during the K‐ion intercalation for further enhancing the stability. As a consequence, the PMC shows a very high capacity of 322 mAh g^?1 at 0.2 A g^?1 over 100 cycles, and can still remain 226 mAh g^?1 at 1.0 A g^?1 for a long period of 1000 cycles, which is among the best‐reported KIBs anodes.     

Biomolecule‐Functionalized Solid‐State Ion Nanochannels/Nanopores: Features and Techniques

Solid‐state ion nanochannels/nanopores, the biomimetic products of biological ion channels, are promising materials in real‐world applications due to their robust mechanical and controllable chemical properties. Functionalizations of solid‐state ion nanochannels/nanopores by biomolecules pave a wide way for the introduction of varied properties from biomolecules to solid‐state ion nanochannels/nanopores, making them smart in response to analytes or external stimuli and regulating the transport of ions/molecules. In this review, two features for nanochannels/nanopores functionalized by biomolecules are abstracted, i.e., specificity and signal amplification. Both of the two features are demonstrated from three kinds of nanochannels/nanopores: nucleic acid–functionalized nanochannels/nanopores, protein‐functionalized nanochannels/nanopores, and small biomolecule‐functionalized nanochannels/nanopores, respectively. Meanwhile, the fundamental mechanisms of these combinations between biomolecules and nanochannels/nanopores are explored, providing reasonable constructs for applications in sensing, transport, and energy conversion. And then, the techniques of functionalizations and the basic principle about biomolecules onto the solid‐state ion nanochannels/nanopores are summarized. Finally, some views about the future developments of the biomolecule‐functionalized nanochannels/nanopores are proposed.     

MoS2/ta‐C‐Kombinationsschichten hergestellt durch Laser‐Arc‐Technologie

MoS₂/ta‐C coatings produced by laserarc‐technology A series of MoS₂ and combined MoS₂/ta‐C coatings were prepared by lasercontrolled arc evaporation (Laser‐Arc) in order to study the tribological coating behaviour under vacuum and atmospheric conditions. Very low friction coefficients down to 0.005 were measured under high vacuum. By using a ta‐C underlayer beneath the MoS₂ a increased lifetime up to 5×10⁵ load cycles could be obtained. Also under atmospheric conditions the underlayer had a beneficial effect on coating performance.