Time filter

Source Type

Molina de Aragón, Spain

De Miguel D.,University of Zaragoza | Gallego-Lleyda A.,University of Zaragoza | Anel A.,University of Zaragoza | Martinez-Lostao L.,University of Zaragoza | Martinez-Lostao L.,Institute Nanociencia Of Aragon
Leukemia Research | Year: 2015

Human Apo2-Ligand/TRAIL is a promising antitumor agent. Our group demonstrated that TRAIL was physiologically released to the extracellular medium inserted in lipid vesicles, known as exosomes. Recently we demonstrated that artificial lipid nanoparticles coated with bioactive TRAIL (LUV-TRAIL), which resemble the natural exosomes, greatly improved TRAIL activity compared with the soluble form of this death ligand and were able to induce apoptosis in hematological malignancies. In this study we have deepened the underlying mechanism of action of LUV-TRAIL in hematologic cells. Using histiocytic lymphoma U937 cells, we demonstrated that TRAIL signaling almost exclusively depends on DR5 despite these cells expressing high amounts of DR4, and proved that LUV-TRAIL's higher pro-apoptotic effect relies on its superior ability to induce DR5 clustering on cell surface, therefore enhancing DISC recruitment and triggering caspase activation more efficiently than the soluble form of TRAIL. © 2015 Elsevier Ltd.

Sebastian N.,University of the Basque Country | Gimeno N.,University of Zaragoza | Vergara J.,University of Zaragoza | Lopez D.O.,Polytechnic University of Catalonia | And 4 more authors.
Journal of Materials Chemistry C | Year: 2014

The synthesis and characterization of three bent-rod dimers are reported. Very long flexible spacers that include methylene units and either a phenyl ring or a triazole moiety as connecting structures join the bent- and rod-promesogenic cores. Polarizing microscopy, modulated differential scanning calorimetry, X-ray diffraction at variable temperature and dielectric measurements have been performed to establish the mesophase behaviour of the dimers. The results show a complex supramolecular organization for this kind of flexible dimer in the mesophase. Interestingly, the length and the chemical nature of the flexible linking spacers condition the liquid crystalline properties of these novel compounds. Additionally, it has been found that the chemical structure of the rod-like core plays a key role in determining the kind of mesophase, either nematic or lamellar, formed by these materials. © 2014 the Partner Organisations.

Serrano J.L.,University of Zaragoza | Serrano J.L.,Institute Nanociencia Of Aragon
Macromolecular Chemistry and Physics | Year: 2012

The synthesis and characterization of ionic liquid crystalline dendritic polymers based on the ammonium salts of commercially available poly(propylene imine) (PPI), poly(amidoamine) (PAMAM), poly(ethyleneimine) (PEI), and the fully methylated PEI (PEIMe) with 5-(4-cyanobiphenoxy)pentanoic acid (CBPA) are reported. The occurrence of proton transfer from the carboxylic acid to the amine groups is confirmed using IR and NMR techniques. The mesomorphic behavior is investigated by means of differential scanning calorimetry, polarizing optical microscopy, and X-ray diffractometry. Although CBPA exhibits monotropic nematic mesomorphism, all ionic complexes display enantiotropic liquid crystal properties. The relationship between the mesomorphism of the complexes and their structure is discussed. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Susi T.,Aalto University | Kaskela A.,Aalto University | Zhu Z.,Aalto University | Ayala P.,University of Vienna | And 14 more authors.
Chemistry of Materials | Year: 2011

Nitrogen-doped single-walled carbon nanotubes (N-SWCNTs) were synthesized using a floating catalyst aerosol chemical vapor deposition method, with carbon monoxide as the carbon source, ammonia as the nitrogen source, and iron particles derived from evaporated iron as the catalyst. The material was deposited on various substrates as grown directly from the gas phase as films and subsequently characterized by Raman and optical absorption spectroscopies, sheet resistance measurements, electron microscopy, energy-loss spectroscopy, and X-ray photoelectron spectroscopy.The sheet resistance measurements revealed that the doped films had unexpectedly high resistances. This stands in contrast to the case of N-MWCNT films, where decreased resistance has been reported with N-doping. To understand this effect, we developed a resistor network model, which allowed us to disentangle the contribution of bundle-bundle contacts when combined with data on undoped films. Assuming doping does not significantly change the contacts, the increased resistances of the doped films are likely due to enhanced carrier scattering by defect sites in the nanotubes. This work represents the first experimental report on macroscopic N-SWCNT thin films. © 2011 American Chemical Society.

Hernandez-Ainsa S.,University of Zaragoza | Barbera J.,University of Zaragoza | Marcos M.,University of Zaragoza | Serrano J.L.,Institute Nanociencia Of Aragon
Macromolecules | Year: 2012

Two novel series of dendrimers constituted by the ionic grafting of poly(propyleneimine) PPI-(NH 2) x (x = 4, 8, 16, 32, 64) and poly(amidoamine) PAMAM-(NH 2) x (x = 64) with carboxylic acids bearing an oxadiazole ring have been synthesized, and their liquid crystalline properties have been investigated. Series I is generated by the ionic attachment between the dendrimers and 1,3,4-oxadiazole-containing acids. Series II results from the ionic junction of the dendrimers to 1,2,4-oxadiazole-containing acids. The liquid crystalline behavior has been investigated by means of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffractometry (XRD). The liquid crystal properties are significantly improved in the dendrimers compared to the mesogenic precursors. The structural parameters determined by X-ray diffraction reflect the different supramolecular organization built by each kind of oxadiazole-containing acid introduced. On the basis of these experimental results, a packing model is proposed based on a microsegregation phenomenon and a variable degree of interdigitation between the mesogenic units. The absorption and emission properties of the compounds have also been studied. To our knowledge, these are the first dendrimers reported up to date combining oxadiazole units and liquid crystal properties. © 2011 American Chemical Society.

Discover hidden collaborations