Magnetic microparticles decorated with enzymes can penetrate mucin, which is a barrier for most particle-based drug carriers.

Locomotion in fluids at the nanoscale is dominated by viscous drag. One efficient propulsion scheme is to use a weak rotating magnetic field that drives a chiral object. From bacterial flagella to artificial drills, the corkscrew is a universally useful chiral shape for propulsion in viscous environments. Externally powered magnetic micro- and nanomotors have been recently developed that allow for precise fuel-free propulsion in complex media. Here, we combine analytical and numerical theory with experiments on nanostructured screw-propellers to show that the optimal length is surprisingly short-only about one helical turn, which is shorter than most of the structures in use to date. The results have important implications for the design of artificial actuated nano- and micropropellers and can dramatically reduce fabrication times, while ensuring optimal performance.

Devising strategies for the controlled injection of functional nanoparticles and reagents into living cells paves the way for novel applications in nanosurgery, sensing, and drug delivery. Here, we demonstrate the light-controlled guiding and injection of plasmonic Janus nanopens into living cells. The pens are made of a gold nanoparticle attached to a dielectric alumina shaft. Balancing optical and thermophoretic forces in an optical tweezer allows single Janus nanopens to be trapped and positioned on the surface of living cells. While the optical injection process involves strong heating of the plasmonic side, the temperature of the alumina stays significantly lower, thus allowing the functionalization with fluorescently labeled, single-stranded DNA and, hence, the spatially controlled injection of genetic material with an untethered nanocarrier.

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Abstract. This minireview discusses whether catalytically active macromolecules and abiotic nanocolloids, that are smaller than motile bacteria, can self-propel. Kinematic reversibility at low Reynolds number demands that self-propelling colloids must break symmetry. Methods that permit the synthesis and fabrication of Janus nanocolloids are therefore briefly surveyed, as well as means that permit the analysis of the nanocolloids' motion. Finally, recent work is reviewed which shows that nanoagents are small enough to penetrate the complex inhomogeneous polymeric network of biological fluids and gels, which exhibit diverse rheological behaviors.

Immobilization of colloidal assemblies onto solid supports via a fast UV-triggered click-reaction is achieved. Transient assemblies of microparticles and colloidal materials can be captured and transferred to solid supports. The technique does not require complex reaction conditions, and is compatible with a variety of particle assembly methods.

Transition metal dichalcogenides (TMD) have attracted immense research interest owing to their 2D stacking molecular structures and the resulted chemical and physical properties. [1] Among various TMD materials, single-crystal molybdenum disulfide (MoS 2) nanoflakes in the 2H-phase, which constitute the basic unit of various crystalline MoS 2 nanostructures and bulk MoS 2 , possess edge sites and in plane sulfur vacancies which for instance show outstanding catalytic activity with an ultralow hydrogen adsorption Gibbs free energy-similar to that of the most efficient platinum and other noble metals. [2] However, in contrast to platinum, MoS 2 is much cheaper, and because it is a semiconductor, its electric conductivity can be readily tuned by the application of a voltage or light. This has been exploited in a variety of applications. For instance, MoS 2 has been demonstrated as an optical and biochemical sensor material. [3] MoS 2 fieldeffect transistors exhibit an on/off ratio as high as ≈10 8 and near-ideal subthreshold Molybdenum disulfide (MoS 2) is a multifunctional material that can be used for various applications. In the single-crystalline form, MoS 2 shows superior electronic properties. It is also an exceptionally useful nanomaterial in its polycrystalline form with applications in catalysis, energy storage, water treatment, and gas sensing. Here, the scalable fabrication of longitudinal MoS 2 nanostructures, i.e., nanoribbons, and their oxide hybrids with tunable dimensions in a rational and well-reproducible fashion, is reported. The nano ribbons, obtained at different reaction stages, that is, MoO 3 , MoS 2 /MoO 2 hybrid, and MoS 2 , are fully characterized. The growth method presented herein has a high yield and is particularly robust. The MoS 2 nanoribbons can readily be removed from its substrate and dispersed in solution. It is shown that functionalized MoS 2 nanoribbons can be manipulated in solution and assembled in controlled patterns and directly on microelectrodes with UV-click-chemistry. Owing to the high chemical purity and polycrystalline nature, the MoS 2 nanostructures demonstrate rapid optoelectronic response to wavelengths from 450 to 750 nm, and successfully remove mercury contaminants from water. The scalable fabrication and manipulation followed by light-directed assembly of MoS 2 nanoribbons, and their unique properties, will be inspiring for device fabrication and applications of the transition metal dichalcogenides.

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