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Abstract: The submicron scale hybrid hollow silica spheres have been fabricated by employing phosphorylated polyethyleneimine as template/scaffold/catalysis in a mild self-assembly biomineralization approach. The highly phosphorylated polyethyleneimine was shown to be a necessary prerequisite for in vitro formation of hollow silica spheres. In the presence of a neutral phosphate buffer, the monovalent anions H2PO4 − and divalent anions HPO4 2− acted not only as the buffer ions but also as ligands, regulating the shape and morphology of the PEI aggregation, which resulted in the final hollow morphology of silica. The hollow silica particles were very uniform in size, with a diameter of 0.8–1.0μm and a shell thickness of ~70nm. [Copyright &y& Elsevier]

Abstract: A layer of macrocyclic calix[4]arene derivatives has been grafted on the internal surface of the mesochannels of the ordered mesoporous SBA-15 to develop highly efficient trap for heavy transition metal (HTM) ions. To ensure the successful anchoring of calix[4]arene derivatives on the surface of SBA-15, two different types of calix[4]arene derivatives, one with one trimethoxysilane functional group and another with two trimethoxysilane functional groups have been explored. XRD, N2 adsorption and TEM results provide strong evidence that the mesoporous structure of the supporting materials retain their long range ordering throughout the grafting process. Solid-state NMR, TG and FT-IR spectroscopy indicate that both types of calix[4]arene derivatives can be well-anchored on the surface of the wall of SBA-15. Calix[4]arene derivative with only one trimethoxysilane functional group showed high grafting efficiency compared to that with two trimethoxysilane functional groups due to the intramolecular and intermolecular polycondensation between two trimethoxysilane functional groups. The HTM ions extraction capacity in aqueous solution of macrocycle functionalized SBA-15 nanohybrides for a series of HTM ions has been studied. The obtained materials demonstrated very high HTM ions extraction capacity up to 96% for Pb2+ in aqueous solution. [Copyright &y& Elsevier]

Abstract: Highly sensitive and selective nanosensor for labile iron pool (LIP) determination, has been designed and prepared by immobilization of Fluoresceine–Desferrioxamine (Fl–DFO), a bifunctional fluoro-siderophore probe molecule with great affinity for iron ions (pKf =30.7), into highly ordered mesoporous silica structure. Different immobilization methods of Fl–DFO molecules, such as their encapsulation in surfactant micelles used as templating agents for the synthesis of mesoporous silica, direct impregnation into the mesochannels of as-synthesized mesoporous silica and their surface anchoring by covalent binding with propylamine groups implanted by post-synthesis on the internal surface of mesochannels, have been explored. Each nanohybrid has been fully characterized by small angle XRD, TEM, SEM, solid state 29Si and 13C MAS NMR and N2 adsorption–desorption. The fluorescence properties of nanohybrids obtained have been correlated with the immobilization methods, generating interesting information concerning the localization of Fl–DFO molecules in the channels of mesoporous silica. The leaching of Fl–DFO molecules from mesoporous materials has been investigated. The nanosensor prepared by surface anchoring of Fl–DFO at the internal surface of mesochannels showed high performances with no leaching effect and high sensitivity in regards to its responses to ferric ions. Its fluorescence intensity decreased as soon as first FeIII ions are in contact with this nanosensor. A linear relationship between the fluorescence intensity and the ferric ions concentration was observed in low micromolar range. The selectivity of this nanosensor towards other metal ions has also been tested and shown its high affinity to ferric ions. This study can allow the design of a stable, portable, simple, regenerable and cost-effective nanosensor highly sensitive and selective for iron ions with detection limits in the range of cellular LIP in cells, e.g. lower micromolar range. [Copyright &y& Elsevier]

This paper reviews our work on the fabrication of photobiochemical hybrid materials viaimmobilisation of photosynthetically active entities within silica materials, summarising the viability and productivity of these active entities post encapsulation and evaluating their efficiency as the principal component of a photobioreactor. Immobilisation of thylakoids extracted from spinach leaves as well as whole cells such as A. thaliana, Synechococcusand C. caldariumwas carried out in situusing sol–gel methods. In particular, a comprehensive overview is given of the efforts to find the most biocompatible inorganic precursors that can extend the lifetime of the organisms upon encapsulation. The effect of matrix–cell interactions on cell lifetime and the photosynthetic efficiency of the resultant materials are discussed. Precursors based on alkoxides, commonly used in “Chimie Douce” to form porous silica gel, release by-products which are often cytotoxic. However by controlling the formation of gels from aqueous silica precursors and silica nanoparticles acting as “cements” one can significantly enhance the life span of the entrapped organelles and cells. Adapted characteristic techniques have shown survival times of up to 5 months with the photosynthetic production of oxygen recorded as much as 17 weeks post immobilisation. These results constitute a significant advance towards the final goal, long-lasting semi-artificial photobioreactors that can advantageously exploit solar radiation to convert polluting carbon dioxide into useful biofuels, sugars or medical metabolites. [ABSTRACT FROM AUTHOR]

Abstract: The present review outlines the research work realized during last the 10 years in our laboratory in the field of the conception of new nanostructured porous materials, from mesoporous silicas and metal oxides to hierarchical meso–macroporous compounds with various compositions (single and binary metal oxides and aluminosilicates, aluminophosphates and silicoaluminophosphates). An accent was especially made on the evolution in the development of new synthesis strategies for the introduction of a hierarchy in one solid body with and without surfactant molecules. To cite this article: B.-L. Su and al, C. R. Chimie 8 (2005). [Copyright &y& Elsevier]

Highlights: [•] A novel class of mesoporous ZnO/silica composites was synthesized. [•] The best materials present a high surface area and narrow pore size distribution. [•] The small ZnO particle size is preserved for all materials (except for the ZnO-100). [•] The materials preserving the mesoporous organization display a high photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Living cells can be considered as a highly efficient molecular engines spatially enclosed, remaining however fragile. By combining cells with silica materials in an appropriate way, novel living hybrid material technologies can be designed. After showing the real interplay between silica species and living organisms in nature, this featuring article summarizes the considerable progress in cell encapsulation into silica matrixes. Generally speaking, bioencapsulation allows protecting cells from harsh environment and controlling their surrounding as well as their concentration. This combination produces ultimately a device that can be oriented to drive the desired biochemical reactions. Particularly, this article highlights that functional living matters are very promising in the development of new eco-friendly processes. Compared to conventional chemical process, these hybrid systems would be enabled to use greater and in more efficient way renewable resources (i.e. solar energy) to produce a vast array of chemicals. Additionally, encapsulated cell technology has opened the possibility to design various other kinds of bioactive materials such as cleaning systems, biosensors and artificial organs. Through different examples, including the immobilization of microorganisms, photosynthetic organelles, plant cells and animal cells, the interests and the preparation methods of these living hybrid materials are discussed. [Copyright &y& Elsevier]

A new pattern of hierarchical ordering, strings of mesoporous silica spheroids, was synthesized at the interface of CO2–water emulsion systems by the utilization of the additive of Na2CO3 and the structure-directing agent of surfactant Brij 97. The strings were self-constructed with spheroidal particles to form linear and branched patterns. Many defects were observed, which should be important in the formation of mesoporous silica spheroids. Templating of CO2–water emulsion was believed to access the pattern in strings. This work provides one example of micro-construction of alternative morphology, which should be significant on designing the novel patterns of mesoporous silica particles. [Copyright &y& Elsevier]

Highlights: [•] Highly ordered mesoporous silica thin films. [•] Control of mesoporous structure and mesochannels orientation. [•] A comprehensive revisit to synthesis parameters. [•] Wettability of different solvent and AFM study. [•] Pore size and surface area determined by Ellipsometry study. [ABSTRACT FROM AUTHOR]

Abstract: A new class of structured mesoporous materials consisting of gallium oxide nanoparticles embedded and stabilised in a silica matrix was designed, synthesised and tested as catalysts for the epoxidation of various alkenes with aqueous hydrogen peroxide. The structure and texture of the mesoporous gallia–silica composites were elucidated by powder X-ray diffraction, isothermal N2 sorption and TEM. The most active epoxidation catalysts are the materials containing 80 and 90% of Ga2O3 nanoparticles. These materials give much higher epoxide yields compared to the parent nanoparticles, thus demonstrating the positive effect of structuring on the catalytic performance. The synthesis of the mesoporous gallia-silica composite catalysts was optimised by investigating the effect of the calcination conditions. Finally, different methods for recycling the catalysts were studied. Mild calcination at 250°C for 3h under controlled N2 flow was identified as the most suitable treatment to retain the catalytic activity upon reuse. [Copyright &y& Elsevier]

Abstract: The wet impregnation of ammonium heptamolybdate onto silica–alumina is used to prepare MoO3/SiO2–Al2O3 heterogeneous metathesis catalysts. The preparation is inspected in details in conjunction with physico-chemical characterization tools with the aim to identify the parameters that dictate the genesis of active and inactive metathesis species. The effects of the MoO3 loading and of the calcination temperature are systematically explored. The samples are characterized by N2-physisorption, ICP-AES, XRD, Raman, 27Al MAS-NMR and XPS and evaluated in the metathesis of propene to butene and ethene. Particular attention is brought to the interaction of the mesoporous silica–alumina support with the active component, to the decomposition of the precursor salt and to the location of the molybdenum oxide phase with respect to the pores of the support. It is shown that the temperature of calcination influences markedly the performances of the catalyst. High temperature treatments are necessary to decompose efficiently the Mo salt precursor. In the metathesis of propylene, the performances are levelling off when the MoO3 loading is increased above ∼8wt.%. This effect is correlated to the build up of MoO3 crystals and of Al2(MoO4)3 at relatively high loading. [Copyright &y& Elsevier]

Abstract: Cyanidium caldarium (Tilden) Geitler SAG 16.91 has been encapsulated within a porous silica host structure to target novel photosynthetic hybrid materials suitable for use in solar cells or CO2 fixation. C. caldarium cells are both thermophilic and acidophilic; on account of these tolerances the hybrid materials could be employed in more extreme heat conditions. TEM highlights that the external cell membrane can remain intact after encapsulation. The images reveal an alignment of silica gel around the external membrane of the cell, providing evidence that the cell wall acts as both a nucleation and polymerisation site for silica species and that the silica scaffold formed by the aggregation of colloidal particles, generates a porosity that can facilitate the transport of nutrients towards the cell. Epifluorescence microscopy and UV–visible spectroscopy have revealed the preservation of photosynthetic apparatus post-immobilisation. Productivity studies showed how the presence of silica nanoparticles within the matrix can adversely interact with the exterior cellular structures preventing the production of oxygen through photosynthesis. [Copyright &y& Elsevier]

Abstract: ZnO@mesoporous silica nanocomposite was prepared by the impregnation of a CMI-1 material in a Zn(NO3)2 solution followed by calcination under O2. Intensive characterization was carried out by N2 adsorption–desorption measurements, scanning and transmission electron microscopy. The optical properties of the ZnO@mesoporous silica nanocomposite were studied by photoluminescence spectroscopy. Quantum Size Effect was firstly demonstrated by subjecting the sample to a 254nm excitation light, and was further confirmed by using a 680nm excitation laser beam, which implies a two-photon absorption process. By focusing the 680nm laser beam on different places in the sample, a very localized random laser effect, also induced by a two-photon absorption process, was detected. [Copyright &y& Elsevier]