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Lopez-Garcia M.,CSIC - Institute of Materials Science | Galisteo-Lopez J.F.,CSIC - Institute of Materials Science | Blanco U.,CSIC - Institute of Materials Science | Lopez C.,CSIC - Institute of Materials Science | Garcia-Martin A.,Institute Microelectronica Of Madrid Imm Csic
Advanced Functional Materials | Year: 2010

The optical properties of two-dimensional hybrid photonic-plasmonic crystals are fine-tuned by modifying the dielectric component of the system. The filling fraction of the dielectric component in monolayers of spheres deposited on gold substrates is controlled by means of oxygen-plasma etching. Doing so enables spectral tuning of the optical modes of the system. Experiments are performed on both optically passive and active samples showing the possibility for strong modification of the emission properties of samples containing emitters distributed within the spheres. The change in sphere diameter needed to substantially modify the sample's optical response points to a potential use of these samples as sensors or tunable emitting devices if appropriate polymeric components are employed. The optical properties of two-dimensional hybrid photonic-plasmonic crystals are fine-tuned by employing oxygen plasma to modify the filling fraction of the lattice. Simulations and experiments agree in showing a high degree of spectral tunability of the modes of the system in a continuous manner. When applied to active samples a strong modification of the emission of internal sources is obtained. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Heredia-Guerrero J.A.,University of Seville | San-Miguel M.A.,University of Seville | Luna M.,Institute Microelectronica Of Madrid Imm Csic | Dominguez E.,Estacion Experimental La Mayora CSIC | And 2 more authors.
Soft Matter | Year: 2011

Soft and spherical nanoparticles, named as cutinsomes, have been prepared from concentrated 9(10),16-dihydroxypalmitic acid (diHPA) in aqueous solution. After isolation, cutinsomes have been chemically and structurally characterized by ATR-FTIR, TEM and dynamic atomic force microscopy (dynamic AFM). The nanoparticle can be described as a lipidic, liquid-like and mostly esterified core surrounded by a polar shell of carboxylate/carboxylic acid molecules. Molecular dynamic (MD) simulations have been used to support this model. The structural stability of soft cutinsomes has been tested by deposition on both non-polar (HOPG) and polar (mica) flat substrates. It has been found that the magnitude of the interaction between the polar shell of cutinsomes and the support determines their structure conservation or its spreading or rupture and spill out of the liquid-like content. The structural consistence of these nanoparticles as a function of the polarity of substrate is of interest in elucidating the formation mechanism of cutin, the most abundant biopolyester in nature and a very interesting biomaterial to be mimetized. © 2011 The Royal Society of Chemistry.

Lopez-Garcia M.,CSIC - Institute of Materials Science | Galisteo-Lopez J.F.,CSIC - Institute of Materials Science | Blanco A.,CSIC - Institute of Materials Science | Sanchez-Marcos J.,CSIC - Institute of Materials Science | And 2 more authors.
Small | Year: 2010

A hybrid photonic-plasmonic crystal structure comprising a close-packed monolayer of dielectric spheres deposited on plasmon-supporting gold substrate is investigated. The spontaneous emission of organic dyes embedded in the beads experiences a strong modification in intensity, polarization, and directionality. These facts are accounted for considering the hybridization of modes arising from the photonic and plasmonic components of the structure. © 2010 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim.

Heredia-Guerrero J.A.,University of Seville | Dominguez E.,Estacion Experimental La Mayora | Luna M.,Institute Microelectronica Of Madrid Imm Csic | Benitez J.J.,University of Seville | Heredia A.,University of Malaga
Chemistry and Physics of Lipids | Year: 2010

In the present work, we report the physico-chemical properties and structural characteristics of special polyhydroxy fatty acid nanoparticles after their fusion by means of attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electronic microscopy (SEM), atomic force microscopy (AFM), and light microscopy. All the characteristics and properties investigated have an important degree of similarity to the native plant cutin, the main biopolymer present in the plant cuticles. The supramolecular organization of these polymerized prime nanoparticles after their interaction on cellulose substrate and isolated cuticle samples, simulating the in vivo conditions in epidermal plant cells, strongly suggests a growth of these nanoparticles after a self-assembly process. © 2010 Elsevier Ireland Ltd. All rights reserved.

Chevalier S.,University of Bordeaux 1 | Cuestas-Ayllon C.,University of Zaragoza | Grazu V.,University of Zaragoza | Luna M.,Institute Microelectronica Of Madrid Imm Csic | And 2 more authors.
Langmuir | Year: 2010

This manuscript describes a novel method for the biofunctionalization of glass surfaces with polyhistidine-tagged proteins. The main innovation of this methodology consists of the covalent binding between the nitrilotriacetic acid (NTA) moiety and the proteins, ensuring not only orientation, but also stability of the recombinant proteins on NTA-covered surfaces. In this work, as C-terminal polyhistidine tagged cadherin extracellular fragments have been used, this methodology guarantees the proper orientation of these proteins, by mimicking their insertion into cell plasma membranes. These biofunctionalized surfaces have been characterized by confocal microscopy, X-ray photoelectron spectroscopy, contact angle, and atomic force microscopy, showing a high density of cadherins on the glass surfaces and the stability of the linkage. The prepared materials exhibited a high tendency to promote cell spreading, demonstrating the functionality of the protein and the high utility of these biomaterials to promote cell adhesion events. Interestingly, differences in the cytoskeleton organization have been observed in cells adhering to surfaces with no cadherins or with nonoriented cadherins, in comparison to surfaces functionalized with well-oriented cadherins. This method, which allows the robust immobilization of polyhistidine tagged proteins due to their covalent binding and with a defined orientation, may also find particular usefulness in the making of protein biochips, for analysis of protein-protein interactions, as well as structural and single-molecule studies. © 2010 American Chemical Society.

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