Search results for "COMPOSITE"
showing 10 items of 4584 documents
Exceptional affinity of nanostructured organic-inorganic hybrid materials towards dioxygen: confinement effect of copper complexes
2007
We report the exceptional reactivity towards dioxygen of a nanostructured organic-inorganic hybrid material due to the confinement of copper cyclam within a silica matrix. The key step is the metalation reaction of the ligand, which can occur before or after xerogel formation through the sol-gel process. The incorporation of a Cu(II) center into the material after xerogel formation leads to a bridged Cu(I)/Cu(II) mixed-valence dinuclear species. This complex exhibits a very high affinity towards dioxygen, attributable to auto-organization of the active species in the solid. The remarkable properties of these copper complexes in the silica matrix demonstrate a high cooperative effect for O(2…
Ce:YAG composites for white LED
2015
Composites and luminescent polymers have been recently found to be potential candidates for the development of white LED, lasers and luminescent concentrators for solar cells. Due to its luminescence properties YAG doped with lanthanides ions is a good candidate as light emitting filler. In a recent our work, the preparation of a polymeric nanocomposite containing Ce:YAG nanoparticles using in situ polymerization has been reported [1]. A good dispersion of Ce:YAG nanoparticles has been obtained maintaining them luminescence properties. In addition, an increase of thermal stability and stiffness of PMMA was observed [2]. Then, the preparation of Ce:YAG-PMMA composite has been performed by us…
Polymeric Ce:YAG nanocomposites: synthesis and characterization
2015
These last years, the development of hybrid polymer-inorganic nanocomposites has been attracted much attention. In particular, composites containing lanthanide-doped materials as filler are candidates for the development of light emitting diodes, lasers and solar cells. Polymers such as polymethylmethacrylate (PMMA), polycarbonate (PC) and polyurethane (PU) are adequate matrices because their good transmission over the visible spectral range, excellent mechanical properties of plasticity, lightness, easiness of fabrication and low cost of mass production. Yttrium aluminum garnet (YAG) doped with Ce(III) ions is one of the yellow phosphor used in the major commercial white LED combined with …
Discovery of new G-quadruplex binding chemotypes
2013
We report here on the discovery and preliminary evaluation of a novel non-macrocyclic low molecular weight quadruplex-stabilizing chemotype. The lead compounds, based on a furan core, show high G-quadruplex stabilisation and selectivity as well as potent in vitro anti-proliferative activity.
Pyrazole[3,4-d]pyrimidine derivatives loaded into halloysite as potential CDK inhibitors
2021
Uncontrolled cell proliferation is a hallmark of cancer as a result of rapid and deregulated progression through the cell cycle. The inhibition of cyclin-dependent kinases (CDKs) activities is a promising therapeutic strategy to block cell cycle of tumor cells. In this work we reported a new example of nanocomposites based on halloysite nanotubes (HNTs)/pyrazolo[3,4-d]pyrimidine derivatives (Si306 and Si113) as anticancer agents and CDK inhibitors. HNTs/Si306 and HNTs/Si113 nanocomposites were synthesized and characterized. The release kinetics were also investigated. Antitumoral activity was evaluated on three cancer cell lines (HeLa, MDA-MB-231 and HCT116) and the effects on cell cycle ar…
Dynamic processes involved in the pre-vascularization of silk fibroin constructs for bone regeneration using outgrowth endothelial cells
2009
For successful bone regeneration tissue engineered bone constructs combining both aspects, namely a high osteogenic potential and a rapid connection to the vascular network are needed. In this study we assessed the formation of pre-vascular structures by human outgrowth endothelial cells (OEC) from progenitors in the peripheral blood and the osteogenic differentiation of primary human osteoblasts (pOB) on micrometric silk fibroin scaffolds. The rational was to gain more insight into the dynamic processes involved in the differentiation and functionality of both cell types depending on culture time in vitro. Vascular tube formation by OEC was assessed quantitatively at one and 4 weeks of cul…
Growth of human cells on polyethersulfone (PES) hollow fiber membranes.
2004
A novel material of porous hollow fibers made of polyethersulfone (PES) was examined for its ability to support the growth of human cells. This material was made in the absence of solvents and had pore diameters smaller than 100 microm. Human cell lines of different tissue and cell types (endothelial, epithelial, fibroblast, glial, keratinocyte, osteoblast) were investigated for adherence, growth, spread and survival on PES by confocal laser microscopy after staining of the cells with Calcein-AM. Endothelial cell attachment and growth required pre-coating PES with either fibronectin or gelatin. The other cell types exhibited little difference in growth, spread or survival on coated or uncoa…
Growth of human cells on a non-woven silk fibroin net: a potential for use in tissue engineering.
2003
We have examined a novel biomaterial consisting of a non-woven fibroin net produced from silk (Bombyx mori) cocoons for its ability to support the growth of human cells. Various human cells of different tissue and cell types (endothelial, epithelial, fibroblast, glial, keratinocyte, osteoblast) were examined for adherence and growth on the nets by confocal laser microscopy after staining of the cells with calcein-AM and by electron microscopy. All the cells readily adhered and spread over the individual fibers of the nets. Most of the cells were able to grow and survive on the nets for at least 7 weeks and growth not only covered the individual fibers of the net but generally bridged the ga…
Spot compliant neuronal networks by structure optimized micro-contact printing
2001
Neuronal cell growth in vitro can be controlled with micropatterned structures of extracellular matrix proteins such as laminin. This technique is a powerful tool for studying neuronal cell function in order to increase experimental reproducibility and to specifically design innovative experimental setups. In this paper the correlation between the structural dimensions of the ECM pattern and the shape of the resulting cellular network is analyzed. The aim of the present study was to position neuronal cell bodies as precisely as possible and to induce directed cell differentiation. PCC7-MzN cells were cultured on laminin patterns. The line width, node size and gap size in-between cell adhesi…
Polysaccharide nanocrystals as fillers for PLA based nanocomposites
2016
The development of green nanocomposites based on biopolymers and bio-based nanofillers has attracted over the recent years the attention of academic and industrial research. Indeed, these nanocomposites could replace some oil-derived polymers and thus helping to overcome environmental problems. In this regard, PLA as matrix and polysaccharide nanocrystals as fillers are the most promising components to obtain high-performance green bio-nanocomposites suitable for different applications, particularly for packaging and biomedical applications. Indeed, at present, due to its processability, mechanical and biological properties, as well as its commercial availability, poly(lactic acid) (PLA) po…