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This work reports a reversible braking system for micromotors that can be controlled by small temperature changes (≈5 °C). To achieve this, gated‐mesoporous organosilica microparticles are internally loaded with metal catalysts (to form the motor) and the exterior (partially) grafted with thermosensitive bottle‐brush polyphosphazenes to form Janus particles. When placed in an aqueous solution of H2O2 (the fuel), rapid forward propulsion of the motors ensues due to decomposition of the fuel. Conformational changes of the polymers at defined temperatures regulate the bubble formation rate and thus act as brakes with considerable deceleration/acceleration observed. As the components can be easily varied, this represents a versatile, modular platform for the exogenous velocity control of micromotors. [ABSTRACT FROM AUTHOR]

The field of imaging has developed considerably over the past decade and recent advances in the area of nanotechnology, in particular nanomaterials, have opened new opportunities. Polymeric nanoparticles are particularly interesting and a number of novel materials, characterized by stimuli-responsive characteristics and fluorescent tagging, have allowed visualization, intracellular labeling and real-time tracking. In some of the latest applications the nanoparticles have been used for imagining of tumor cells, both in vivo and ex vivo. [ABSTRACT FROM AUTHOR]

Three new hybrid gated mesoporous materials ( SN3-1, SNH2-2, and SN3-3) loaded with the dye [Ru(bipy)3]2+ (bipy=bipyridine) and capped with different tetrathiafulvalene (TTF) derivatives (having different sizes and shapes and incorporating different numbers of sulfur atoms) have been prepared. The materials SN3-1 and SN3-3 are functionalized on their external surfaces with the TTF derivatives 1 and 3, respectively, which were attached by employing the 'click' chemistry reaction, whereas SNH2-2 incorporates the TTF derivative 2, which was anchored to the solid through an amidation reaction. The final gated materials have been characterized by standard techniques. Suspensions of these solids in acetonitrile showed 'zero release', most likely because of the formation of dense TTF networks around the pore outlets. The release of the entrapped [Ru(bipy)3]2+ dye from SN3-1, SNH2-2, and SN3-3 was studied in the presence of selected explosives (Tetryl, TNT, TNB, DNT, RDX, PETN, PA, and TATP). SNH2-2 showed a fairly selective response to Tetryl, whereas for SN3-1 and SN3-3 dye release was found to occur with Tetryl, TNT, and TNB. The uncapping process in the three materials can be ascribed to the formation of charge-transfer complexes between the electron-donating TTF units and the electron-accepting nitroaromatic explosives. Finally, solids SNH2-2 and SN3-1 have been tested for Tetryl detection in soil with good results, pointing toward a possible use of these or similar hybrid capped materials as probes for the selective chromo-fluorogenic detection of nitroaromatic explosives. [ABSTRACT FROM AUTHOR]

Manganese ions are embedded in microporous silica nanoparticles to catalyse the degradation of the H SB 2 sb O SB 2 sb "fuel" to water and gaseous oxygen. Keywords: bottle-brush polymers; mesoporous silica; micromotors; microparticles; polyphosphazenes EN bottle-brush polymers mesoporous silica micromotors microparticles polyphosphazenes 3187 3187 1 02/17/21 20210215 NES 210215 B Self-propelled micromotors b with a reversible braking system are shown. Manganese ions are embedded in microporous silica nanoparticles to catalyse the degradation of the H SB 2 sb O SB 2 sb "fuel" to water and gaseous oxygen. [Extracted from the article]

To celebrate International Women′s Day on March 8th 2016, Chemistry – A European Journal is publishing a special issue dedicated to women around the world currently working in chemical research. The cover picture shows the frontispieces of the Concept, Review, and Minireview articles published in this issue, highlighting the broad range of chemistry that is currently being carried out by female researchers. In the top row from left to right: S. Harutyunyan et al. (page 3558 ff.), J. Sponer et al. (page 3572 ff.), and M. Brimble et al. (page 3622 ff.). In the middle row from left to right: M. Resmini et al. (page 3612 ff.), the logo for International Women′s Day 2016 (http://www. internationalwomensday.com/), and Y. Xie and J. Xie (page 3588 ff.). In the bottom row from left to right: I. Beletskaya and P. Sazonov (page 3644 ff.), T. Gaich and M. Pfaffenbach (page 3600 ff.), and A. Lattanzi and S. Meninno (page 3632 ff.). [ABSTRACT FROM AUTHOR]