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Abstract: Spherical mesoporous particles functionalized with carboxylic groups were prepared through a co-condensation route by spraying a solution containing hydrolyzed alkoxide (tetraethoxysilane) and an organosilane (4-(triethoxysilyl) butyronitrile)), in the presence of nonionic block copolymer as template. Samples have been then treated with sulfuric acid to remove the template and to hydrolyze simultaneously the –CN to –COOH groups. The mesoporous spheres show high specific surface area and narrow pore size distribution. TG and FT-IR analysis confirm the incorporation of the carboxylic moieties, whose amount results ca 1meqg−1 by titration with alkali solution. The mean size of mesoporous spheres can be ranged from few microns to submicron by varying the initial precursor concentration of spray-dried synthesis solution. [Copyright &y& Elsevier]

The paper reports the synthesis of an ordered silica mesostructure of the SBA-15 type inside a macroporous bioactive glass–ceramic scaffold of the type SiO2–CaO–K2O, to combine the bioactivity of the latter with the release properties of the former, in view of local drug delivery from implants designed for tissue engineering. The standard procedure for SBA-15 synthesis has been modified to minimize the damage to the scaffold caused by the acidic synthesis medium. The composite system has been characterized by means of Scanning Electron Microscopy (coupled with EDS analysis), Small Angle X-Ray Diffraction, Thermogravimetry analysis and Infrared Spectroscopy: the formation of a well ordered hexagonal mesostructure was confirmed. Ibuprofen has been chosen as model drug. The uploading properties have been investigated of the scaffold-mesoporous silica composite as compared with the scaffold as such, and a five-fold increase in the adsorbing properties toward ibuprofen was found, due to the presence of the ordered mesoporous silica. The ibuprofen release to a SBF solution in vitro is complete in 1 day. Retention of bioactivity from the glass–ceramic scaffold after the silica mesostructure incorporation has been observed. [ABSTRACT FROM AUTHOR]

Abstract: A hybrid CTABr-silica mesophase of the MCM-41 structure type has been synthesized which hosts molecules of methylene blue (MB). XRD and UV–Vis evidence show that MB molecules act as co-surfactant and are located in the proximity of the internal silica surface. Their electrochemical activity has been studied by means of cyclic voltammetry (CV) and compared to that of MB adsorbed on surfactant-free MCM-41, and in aqueous solutions. MB molecules are not released to the solution during CV measurements and are accessible to H3O+ species. The presence of micelles affects the kinetics of the redox process through H3O+ diffusion. With the hybrid system, a second MB species is observed, probably in prevailing interaction with the micelle. [Copyright &y& Elsevier]