Time and time again humanity is faced with a unifying global crisis that crosses the many great divides in different societies and serves to bring once segregated communities back together as a collective whole. This global community instinctively turns to science to develop the means of addressing its most pressing problems. More often than not, these forces dictate the direction that scientific research takes. This influence is no more apparent than in the field of supramolecular chemistry where, for decades now, its responsibility to tackle such issues has been put on the back burner as a consequence of a lack of platforms with which to deliver this contemporary brand of chemistry to meaningful applications. However, the tide is slowly turning as new materials emerge from the field of nanotechnology that are poised to host the many attractive attributes that are inherent in the chemistry of these supermolecules and also in the mechanostereochemistry of mechanically interlocked molecules (MIMs), which can be reused as a sequel to supramolecular chemistry. Mesoporous silica nanoparticles (SNPs) have proven to be supremely effective solid supports as their surfaces are easily functionalised with either supermolecules or MIMs. In turn, the blending of supramolecular chemistry and mechanostereochemistry with mesoporous SNPs has led to a new class of materials - namely, mechanised SNPs that are effectively biological nanoscale 'bombs' that have the potential to infiltrate cells and then, upon the pulling of a chemical trigger, explode! The development of these materials has been driven by the need to devise new therapies for the treatment of cancer. Recent progress in research promises not only to control the acuteness of this widespread and insidious disease, but also to make the harsh treatment less debilitating to patients. This global scourge is the unifying force that has brought together supramolecular chemistry, mechanostereochemistry and nanotechnology, uniting these three communities for the common good. At the nanoscale level, the mechanism for the release of cargos from the confines of the nanopores in the SNPs is accomplished by way of mechanical modifications made on the surface of these functionalised supports. These mechanical motions rely on both supramolecular, i.e., host-guest complexes, and mechanostereochemical phenomena (e.g., bistable rotaxanes), which are often stimulated by changes in pH, light and redox potentials, in addition to enzymatic catalysis. The future of this field lies in the development of 'smart bombs' wherein the loaded mechanised SNPs are endocytosed selectively by cancer cells, whereupon an intracellular trigger causes release of a cytotoxin, effectively leading to apoptosis. This review serves to highlight (1) the evolution of surface-functionalisation of SNPs with supermolecules and also with MIMs, (2) the mechanisms through which controlled-release of cargo from mechanised SNPs occurs, and (3) results from the in vitro application of these mechanised SNPs.

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Redox-driven mechanical movement, which has been achieved for a liquid-crystalline (LC) bistable [2]rotaxane in the LC phase, is accompanied by obvious electrochromism (electrochemically induced changes in color) of the material. The dumbbell-shaped LC [2]rotaxane with redox-active moieties, which interlocks with an ionic macrocycle, forms ordered redox-active condensed states.

An efficient, site-specific and scalable approach has been developed to produce high-quality and individually addressable conducting polymer nanowire electrode junctions (CPNEJs) in a parallel-oriented array. Polypyrrole and PEDOT conducting polymer nanowires (CPNWs) with uniform diameters (ca. 60-150 nm) were introduced into the desired electrode junctions in a precise manner by performing a three-step constant-current electrochemical process at a low current density and a low concentration of monomers. A low scan rate, cyclic voltammetric method was also employed and gave similar results. These CPNEJ arrays function as a miniaturized sensor for the parallel and real-time detection of gas and organic vapour. The electrochemical approaches utilized allow the conducting polymer chains to self-organize in the CPNWs to form novel polycrystalline structures, observed by high resolution TEM. The weak diffraction rings at 4.88 Å and 4.60 Å were observed for PEDOT and polypyrrole CPNWs, respectively.

A new type of dynamic micromixer combining the concepts of parallel multi-lamination and hydrodynamic focusing was developed for arbitrary control of disguised chemical selectivity.Microreactors are microscopic reaction settings that exhibit unique properties versus traditional macroscopic environments: advantages of microreactors include reduced reagent consumption, high surface-area-to-volume ratios and improved control over mass and heat transfer. [1][2][3][4][5][6][7][8] In addition, fluidic physical phenomena in the microreactors are dramatically different from those observed in the macroscopic reaction apparatuses. [9][10][11] For instance, the inertial effect in the microfluidic environment is negligible (due to a low value of Reynolds number, Re), and thus fluid transport is dictated by fluid viscosity, leading to laminar flow in microchannels. A microfluidics-based reactor is known to be a turbulence-free system, in which diffusion-driven mixing is relatively slow. As a result, one of the most challenging issues in the field of microreactor design is to facilitate mixing in stand-alone devices. Over the past decades enormous efforts have been devoted to develop micromixers (one type of microreactor) that can be categorized into either active or passive ones. 12 Unlike active micromixers, passive ones13 do not require external power, are often composed of robust channel geometry or microstructures, and are developed upon straightforward concepts of increasing contact surfaces and/or shortening the distance for diffusion among different streams. For example, devices based on parallel14 -16 multi-lamination 12 have been developed to achieve efficient mixing. † Mixing may impact reaction outcomes. 17,18 A good example is the diazo coupling reaction 19 between 4-sulfono-benzenediazonium (1) and 1-naphthol (2) under alkaline conditions at room temperature. This reaction is known as a fast competitive consecutive reaction 20 (Scheme 1), where the selectivity between the two major reaction products (i.e., monosubstituted product 3 and disubstituted product 4) is not only determined by intrinsic reaction kinetics 21 (k 1 = 1.2 × 10 7 M −1 s −1 and k 2 = 2 × 10 3 M −1 s −1 ) but also affected by the mixing rates. When reactants 1 and 2 are mixed in a macroscopic setting, the reaction solution is first fragmented by stir-induced turbulence. No matter what mixing approach (e.g., hand mixing or mechanical stirring) is applied, in the best case scenario, the mean radii of the fragmentized solutions are approximately in the range of 100 to 1000 µm, 22,23 leading to a mixing time ranging from a millisecond to seconds. Consequently, the fast reaction between the 1 and 2 happens prior to complete homogeneous mixing to give a complicated reaction mixture containing reactant 2 and products 3 and 4. This phenomenon is known as the disguised chemical selectivity. 20,24,25 In order to avoid the undesired disguised chemical selectivity, micromixers exhibiting fast mixing rates have been developed. 4,20 In this paper,...