Structure and Luminescence Properties of Eu3+-Doped Cubic Mesoporous Silica Thin Films

Eu3+ ions-doped cubic mesoporous silica thin films with a thickness of about 205 nm were prepared on silicon and glass substrates using triblock copolymer as a structure-directing agent using sol–gel spin-coating and calcination processes. X-ray diffraction and transmission electron microscopy analysis show that the mesoporous silica thin films have a highly ordered body-centered cubic mesoporous structure. High Eu3+ ion loading and high temperature calcination do not destroy the ordered cubic mesoporous structure of the mesoporous silica thin films. Photoluminescence spectra show two characteristic emission peaks corresponding to the transitions of5D0-7F1 and 5D0-7F2 of Eu3+ ions located in low symmetry sites in mesoporous silica thin films. With the Eu/Si molar ratio increasing to 3.41%, the luminescence intensity of the Eu3+ ions-doped mesoporous silica thin films increases linearly with increasing Eu3+ concentration

Control of internal (2D and 3D hexagonal) mesostructure and particle morphology of spherical mesoporous silica particles using the emulsion and solvent evaporation (ESE) method

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Ex vivo alendronate localization at the mesoporous titania implant/bone interface

An attractive approach in implant technology is local drug delivery, and design of efficient, safe and reliable treatments. Our\ua0hitherto strategy has been to coat Ti implants with a thin mesoporous TiO2 film that in turn\ua0is loaded with an osteoporosis drug, such as Alendronate (ALN) that is known to suppress osteoclastic activity. This system has proven highly successful and results in excellent osseointegration. However, more detailed information about drug-release and distribution at the bone/implant interface is needed. In this study, (14)C-ALN loaded titanium implants were placed up to 8\ua0weeks into rat tibia and the spatial-temporal distribution of the drug was evaluated. Autoradiography data demonstrated a sustained release of (14)C-ALN and the released\ua0drug remained bound to bone in close vicinity, within 500 micrometers,\ua0of the implants. Liquid scintillation counting experiments confirmed that the distal transport of released (14)C-ALN was extremely low. The results are favorable as they show that ALN stays for a long time in the vicinity of the implant and may therefore improve for a long time the mechanical fixation of bone anchored implants. Moreover, these findings suggest due to the low systemic spreading a minimal risk of Alendronate related systemic side effects

Peptide-induced formation of a tethered lipid bilayer membrane on mesoporous silica

Tethered bilayer lipid membranes (tBLMs) on solid supports have substantial advantages as models of artificial cell membranes for such biomedical applications as drug delivery and biosensing. Compared with untethered lipid membranes, tBLMs have more space between substrate and the bilayer and greater stability. The purpose of this work was to use these properties to fabricate and characterize a zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine lipid tBLM containing 2 mol % 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-maleimide(poly(ethylene glycol))-2000 (DSPE-PEG2000-NHS) lipid tethers on a 3-aminopropyltrimethoxysilane-modified mesoporous silica substrate. A quartz crystal microbalance with dissipation monitoring was used to monitor the process of vesicle adsorption and tBLM self-assembly, and atomic force microscopy was performed to characterize the structural properties of the tBLM obtained. Whereas tether-containing lipid vesicles ruptured neither spontaneously nor as a result of osmotic shock, introduction of an amphipathic α-helical (AH) peptide induced vesicle rupture and subsequent tBLM formation. Taken together, our findings suggest that the AH peptide is an efficient means of rupturing vesicles of both simple and complex composition, and is, therefore, useful for formation of tBLMs on solid and mesoporous materials for applications in biotechnology.NRF (Natl Research Foundation, S’pore)NMRC (Natl Medical Research Council, S’pore