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Curcumin is a natural active principle with antioxidant, antibacterial and anti-inflammatory properties. Its use is limited by a low water solubility and fast degradation rate, which hinder its bioavailability. To overcome this problem, curcumin can be delivered through a carrier, which protects the drug molecule and enhances its pharmacological effects. The present work proposes a simple one-pot sol–gel synthesis to obtain a hybrid carrier for curcumin delivery. The hybrid consists of a mesostructured matrix of amorphous silica, which stabilizes the carrier, and hexadecyltrimethylammonium (CTA), a surfactant where curcumin is dissolved to increase its water solubility. The carrier was characterized in terms of morphology (FESEM), physicochemical properties (XRD, FTIR, UV spectroscopy) and release capability in pseudo-physiological solutions. Results show that curcumin molecules were entrapped, for the first time, in a silica-surfactant mesostructured hybrid carrier. The hybrid carrier successfully released curcumin in artificial sweat and in a phosphate buffer saline solution, so confirming its efficacy in increasing curcumin water solubility. The proposed drug release mechanism relies on the degradation of the carrier, which involves the concurrent release of silicon. This suggests strong potentialities for topical administration applications, since curcumin is effective against many dermal diseases while silicon is beneficial to the skin.

Surfactant-templating is one of the most versatile and useful techniques to implement mesoporous systems into solid materials. Various strategies based on various interactions between surfactants and solid precursors have been explored to produce new structures. Zeolites are invaluable as size- and shape-selective solid acid catalysts. Nevertheless, their micropores impose limitations on the mass transport of bulky feed and/or product molecules. Many studies have attempted to address this by utilizing surfactant-assisting technology to alleviate the diffusion constraints. However, most efforts have failed due to micro/mesopore phase separation. Recently, a new technique combining the uses of cationic surfactants and mild basic solutions was introduced to synthesise mesostructured zeolites. These materials sustain the unique characteristics of zeolites (i.e., strong acidity, crystallinity, microporosity, and hydrothermal stability), including tunable mesopore sizes and degrees of mesoporosity. The mesostructured zeolites are now commercially available through Rive Technology, and show superior performance in VGO cracking. This feature article provides an overview of recent explorations in the introduction of mesoporosity into zeolites using surfactant-templating techniques. Various porous materials, preparation methods, physical and catalytic properties of mesostructured zeolites will be discussed.

International audience; Building mesostructured biomaterials is a challenging and exciting task that has attracted much attention because of their use as drug carriers or drug delivery systems. In the case of bioactive materials, the mesostructuration can also deeply impact their physico-chemical properties and the reactivity. In this study, we show how highly ordered mesoporosity influence the early steps of biomineralization process and the reactivity in binary (SiO2-CaO) and ternary (SiO2-CaO-P2O5) bioactive glasses. Conventional porous sol-gel glasses were synthesized using a classical route, while mesostructured glasses were elaborated using a non-ionic surfactant. Textural properties of these materials have been characterized. The in vitro biomineralization process was followed, using Particle Induced X-ray Emission (PIXE) associated to Rutherford Backscattering, Spectrometry (RBS), which are efficient methods for a highly sensitive multi-elemental analysis. Elemental maps of silicon, calcium and phosphorus were obtained at a micrometer scale and revealed for the first time a bulk reactivity for mesostructured glasses. This is a major advantage over conventional glasses, for which the first steps of biomineralization are limited to the periphery of the material. Their enhanced bioactivity combined with their possible use as drug-delivery systems make them promising candidates for bone regeneration.

International audience; An investigation of the porosity of a thin mesoporous titania film was performed using both ellipsoporosimetry and thermoporometry. These films are prepared using the sol-gel process with a block copolymer PEO-PPO-PEO (P123) and a thermal treatment at 350 degrees C. The film is constituted by a single layer with oblate pores whose small and high diameters are respectively equal to 5 and 7 nm. The porous volume is 31% or 36% depending of the method used. The porous titania film has also been used as a template for the growth of silver nanoparticles. Impregnation of the porous film in a silver salt solution is followed by a reduction step with sodium borohydride. Ellipsoporosimetry is then the only way to study the porosity, using a two-layer model. The first thin layer (35 nm) is slightly porous and contains a lot of large silver nanoparticles. The second under layer is thicker (180 nm) and has a porosity similar to the empty layer one.

The structure of the preformed LC mesophase of water:transition metal salt ([M(H2O)6]X2):acid (HX):oligo(ethylene oxide) (or Pluronics):tetramethylorthosilicate (TMOS) mixture during hydrolysis and partial polymerization of the silica source is maintained upon further polymerization and condensation of the silica species in the solid state. The liquid mixture in early stage of the silica polymerization could be casted or dip coated to a surface of a glass or silicon wafer to produce mesostructured silica monoliths and films, respectively. The silica species and ions (metal ions and anions) influence the structure of the LC mesophases (as a result, the structure of silica) and the hydrophilic and hydrophobic balance in the reaction media. The silica structure can be changed from hexagonal to cubic by increasing, for example, the nitrate salt concentration in the nitrate salt systems. A similar transformation takes place in the presence of very low perchlorate salt concentration. The salt concentration in the mesostructured silica can be increased up to 1.1/1.0 salt/SiO2 w/w ratio, in mesostructured silica materials by maintaining its lamella structure in P123 and cubic in the CnEOm systems. However, the materials obtained from the P123 systems undergo transformation from lamella to 2D hexagonal upon calcinations. The method developed in this work can be used to modify the internal surface of the pores with various transition metal ions and metal oxides that may find application in catalysis. © 2006 Elsevier Inc. All rights reserved.

Transition metal salt-pluronic liquid crystalline (TMS-PLC) mesophases of A-P85, B-P85 and ((1 - x)A + xB)-P85 (where A is [Cd(H2O) 4](NO3)2, B is [Zn(H2O) 6](NO3)2 and P85 is a triblock copolymer, HO(CH2CH2O)26(CH2(CH 3)CHO)40(CH2CH2O)26H) have been used to produce mesostructured metal sulfide films. The TMS-PLC mesophases of A-P85, B-P85 and (A + B)-P85 are well ordered with a salt/P85 mole ratio between 3.0 and 11.0 with a 3D hexagonal structure. The reaction between the mesophases of A-P85, B-P85 and ((1 - x)A + xB)-P85 and H2S gas at room temperature produces mesostructured CdS, ZnS and Cd1-xZn xS films, respectively. The initial salt concentrations in the TMS-PLC phase determine the final Cd(ii) and Zn(ii) ions in the Cd 1-xZnxS crystal structure, where x can be controlled between 0.0 and 1.0. Fresh samples of the mesophase reacted under an H 2S atmosphere are continues films that slowly leach out excess P85 producing P85 rich dendrite domains and aggregates of 50 to 100 nm particles of mesostructured CdS, ZnS or Cd1-xZnxS. However, well homogenized TMS-PLC mesophases produce stable film samples upon H2S reaction.

Supramolecular self-assembling of organic CTA+ micelles and inorganic [VO(H2O)PO4]n^q-2 2D-anions for the isolation of hexagonal mesostructured materials can be reached by charge tuning in the inorganic phase through the adjustment of the vanadium mean oxidation state. El Haskouri, Jamal, Jamal.Haskouri@uv.es ; Cabrera Medina, Saul, Saul.Cabrera@uv.es ; Beltran Porter, Aurelio, Aurelio.Beltran@uv.es ; Alamo Serrano, Jaime, Jaime.Alamo@uv.es ; Beltran Porter, Daniel, Daniel.Beltran@uv.es ; Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es