Microporous metal-organic frameworks (MOFs) that display permanent porosity show great promise for a myriad of purposes. The potential applications of MOFs can be developed further and extended by encapsulating various functional species (for example, nanoparticles) within the frameworks. However, despite increasing numbers of reports of nanoparticle/MOF composites, simultaneously to control the size, composition, dispersed nature, spatial distribution and confinement of the incorporated nanoparticles within MOF matrices remains a significant challenge. Here, we report a controlled encapsulation strategy that enables surfactant-capped nanostructured objects of various sizes, shapes and compositions to be enshrouded by a zeolitic imidazolate framework (ZIF-8). The incorporated nanoparticles are well dispersed and fully confined within the ZIF-8 crystals. This strategy also allows the controlled incorporation of multiple nanoparticles within each ZIF-8 crystallite. The as-prepared nanoparticle/ZIF-8 composites exhibit active (catalytic, magnetic and optical) properties that derive from the nanoparticles as well as molecular sieving and orientation effects that originate from the framework material.

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The use of nanomaterials has raised safety concerns, as their small size facilitates accumulation in and interaction with biological tissues. Here we show that exposure of endothelial cells to TiO 2 nanomaterials causes endothelial cell leakiness. This effect is caused by the physical interaction between TiO 2 nanomaterials and endothelial cells' adherens junction protein VE-cadherin. As a result, VE-cadherin is phosphorylated at intracellular residues (Y658 and Y731), and the interaction between VE-cadherin and p120 as well as b-catenin is lost. The resulting signalling cascade promotes actin remodelling, as well as internalization and degradation of VE-cadherin. We show that injections of TiO 2 nanomaterials cause leakiness of subcutaneous blood vessels in mice and, in a melanoma-lung metastasis mouse model, increase the number of pulmonary metastases. Our findings uncover a novel non-receptor-mediated mechanism by which nanomaterials trigger intracellular signalling cascades via specific interaction with VE-cadherin, resulting in nanomaterial-induced endothelial cell leakiness.

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The recent developments of hetero-nanostructures for photocatalytic H2production and CO2reduction are reviewed in detail, based on material compositions that form heterojunctions.

In this paper, we report a novel strategy for surface treatment of hematite nanorods for efficient photodriven water oxidation. This is the first report describing the growth of Sn treated hematite from a-FeOOH nanorod arrays in one step without substantially altering morphologies. With this treatment the photocurrent density increased from 1.24 for pristine hematite nanorods to 2.25 mA cm À2 at 1.23 V vs. RHE (i.e. 81% improvement). The increase in photocurrent density was also accompanied by improved incident-photon-to-current efficiencies and oxygen evolution. The photocurrent improvement is mainly attributed to a reduced electron-hole recombination at the hematite-electrolyte interface through the formation of Fe x Sn 1Àx O 4 layer at the hematite nanorod surface as shown by XPS, HRTEM, EDAX line scan analyses and PEC measurements.

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