6 results on '"Luis, Yate"'
Search Results
2. Acetate-Induced Disassembly of Spherical Iron Oxide Nanoparticle Clusters into Monodispersed Core–Shell Structures upon Nanoemulsion Fusion
- Author
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Grzegorz Nowaczyk, Stefan Jurga, Luis Yate, Jacek Gapiński, Sławomir Milewski, Ahmet Kertmen, Carmen Vogt, Emerson Coy, Pau Torruella, Muhammet S. Toprak, Francesca Peiró, Ryszard Andruszkiewicz, and Sònia Estradé
- Subjects
Solid-state chemistry ,Chemistry ,Inorganic chemistry ,Ethyl acetate ,Iron oxide ,Nanoparticle ,02 engineering and technology ,Surfaces and Interfaces ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Chemical reaction ,Article ,0104 chemical sciences ,Tetraethyl orthosilicate ,chemistry.chemical_compound ,Pulmonary surfactant ,Chemical engineering ,Electrochemistry ,General Materials Science ,0210 nano-technology ,Spectroscopy ,Iron oxide nanoparticles - Abstract
It has been long known that the physical encapsulation of oleic acid-capped iron oxide nanoparticles (OA–IONPs) with the cetyltrimethylammonium (CTA+) surfactant induces the formation of spherical iron oxide nanoparticle clusters (IONPCs). However, the behavior and functional properties of IONPCs in chemical reactions have been largely neglected and are still not well-understood. Herein, we report an unconventional ligand-exchange function of IONPCs activated when dispersed in an ethyl acetate/acetate buffer system. The ligand exchange can successfully transform hydrophobic OA–IONP building blocks of IONPCs into highly hydrophilic, acetate-capped iron oxide nanoparticles (Ac–IONPs). More importantly, we demonstrate that the addition of silica precursors (tetraethyl orthosilicate and 3-aminopropyltriethoxysilane) to the acetate/oleate ligand-exchange reaction of the IONPs induces the disassembly of the IONPCs into monodispersed iron oxide–acetate–silica core–shell–shell (IONPs@acetate@SiO2) nanoparticles. Our observations evidence that the formation of IONPs@acetate@SiO2 nanoparticles is initiated by a unique micellar fusion mechanism between the Pickering-type emulsions of IONPCs and nanoemulsions of silica precursors formed under ethyl acetate buffered conditions. A dynamic rearrangement of the CTA+–oleate bilayer on the IONPC surfaces is proposed to be responsible for the templating process of the silica shells around the individual IONPs. In comparison to previously reported methods in the literature, our work provides a much more detailed experimental evidence of the silica-coating mechanism in a nanoemulsion system. Overall, ethyl acetate is proven to be a very efficient agent for an effortless preparation of monodispersed IONPs@acetate@SiO2 and hydrophilic Ac–IONPs from IONPCs.
- Published
- 2017
3. Nanoscale Effects of Radiation (UV, X-ray, and γ) on Calcite Surfaces: Implications for its Mechanical and Physico-Chemical Properties
- Author
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Krzysztof Tadyszak, Zuzanna Kabacińska, Ryszard Krzyminiewski, M. Wencka, Luis Yate, and Emerson Coy
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Calcite ,Materials science ,X-ray ,Mineralogy ,02 engineering and technology ,Nanoindentation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,General Energy ,Calcium carbonate ,X-ray photoelectron spectroscopy ,chemistry ,Chemical engineering ,Irradiation ,Physical and Theoretical Chemistry ,0210 nano-technology ,Elastic modulus ,Biomineralization - Abstract
Calcite, the most stable polymorph of calcium carbonate (CaCO3), attracts growing attention due to its wide applications in many fields, such as composite materials, food industry, biomineralization, and dating of archeological and geological objects. Our study shows the influence of UV, X-ray and γ-radiation on the mechanical and physicochemical properties of calcite at the nanoscale. Using nanoindentation technique we observed a clear detriment in the mechanical response (hardness and elastic modulus) of the calcite (104) surface after irradiation, most visible in the case of UV. Changes in mechanical properties were correlated with the accumulation of radiation defects detected using EPR spectroscopy, and information on chemical bonding and composition obtained through XPS analyses. Additionally, the efficiency in generating defects for all three types of radiation was compared, which allowed us to propose a possible mechanism of UV-induced formation of radiation defects in calcite.
- Published
- 2017
4. Study of the Impact of Polyanions on the Formation of Lipid Bilayers on Top of Polyelectrolyte Multilayers with Poly(allylamine hydrochloride) as the Top Layer
- Author
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Hendrik Heinz, Christopher Kirby, Luis Yate, Ronald F. Ziolo, Sergio Moya, Eleftheria Diamanti, Patrizia Andreozzi, Edwin Donath, and Ramiro Anguiano
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Chemistry ,Vesicle ,Bilayer ,technology, industry, and agriculture ,02 engineering and technology ,Quartz crystal microbalance ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Polyelectrolyte ,0104 chemical sciences ,Surfaces, Coatings and Films ,Allylamine ,Polystyrene sulfonate ,chemistry.chemical_compound ,Chemical engineering ,Materials Chemistry ,Organic chemistry ,lipids (amino acids, peptides, and proteins) ,Physical and Theoretical Chemistry ,0210 nano-technology ,Lipid bilayer ,Acrylic acid - Abstract
The impact of polyanions on the formation of lipid bilayers on top of polyelectrolyte multilayers (PEMs) with poly(allylamine hydrochloride) (PAH) as the top layer is studied for the deposition of vesicles of mixed lipid composition, 50:50 molar ratio of zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and negatively charged 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS). PEMs are assembled with polystyrene sulfonate (PSS), poly(acrylic acid) (PAA), and alginic acid sodium salt (Alg) as polyanions. The assembly of the vesicles on the PEMs is followed by means of the quartz crystal microbalance with dissipation. Fluorescence recovery after photobleaching measurements are applied to evaluate bilayer formation. Whereas a bilayer is formed on top of PAH/PSS multilayers, the vesicles are adsorbed on top of PAH/Alg and PAH/PAA multilayers, remaining unruptured or only partially fused. The influence of the surface composition of the PEM and of the bulk properties of the film are analyzed. The phosphate ions present in phosphate-buffered saline (PBS) play a fundamental role in bilayer formation on top of PAH/PSS as they complex with PAH and render the surface potential close to zero. For PAH/PAA and PAH/Alg, PBS renders the surface negative. X-ray photoelectron spectroscopy shows that the dibasic phosphate ions from PBS complex preferentially with PAH in PAH/PAA and PAH/Alg multilayers, whereas monobasic phosphates complex with PAH in PAH/PSS. An explanation for the absence of bilayer formation on PAH/PAA and PAH/Alg is given on the basis of the different affinities of phosphate ions for PAH in combination with the different polyanions.
- Published
- 2017
5. Nanostructured and Selective Filter To Improve Detection of Arsenic on Surface Plasmon Nanosensors
- Author
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Yulieth Catherine Reyes Roa, Stefan Jurga, CIC BiomaGUNE, Luis Emerson Coy Romero, Edgar E Gonzalez, and Luis Yate
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Fluid Flow and Transfer Processes ,Suspended solids ,Materials science ,Process Chemistry and Technology ,Surface plasmon ,Inorganic chemistry ,chemistry.chemical_element ,Bioengineering ,02 engineering and technology ,010501 environmental sciences ,Contamination ,021001 nanoscience & nanotechnology ,01 natural sciences ,Mercury (element) ,Arsenic contamination of groundwater ,chemistry ,Nanosensor ,Environmental chemistry ,Surface plasmon resonance ,0210 nano-technology ,Instrumentation ,Arsenic ,0105 earth and related environmental sciences - Abstract
The development of a pretreatment system to assist surface plasmon sensor-based measurement of arsenic in water is described. The system proposed addresses important issues, regarding the reliable in situ detection of arsenic in water. This system uses a primary filter made of nonactivated cotton fibers for particulate matter and chemical retention agents without modifying the arsenic concentration in the water sample. A secondary filter was designed for retention of mercury, lead, and other heavy metals without alteration of the arsenic concentration in the collected water samples to be sensed. This filter was made with amino-functionalized carbon nanotubes. The results of the operational assessment of this filter show a retention efficiency of 98% for suspended solids, 96% for mercury ions, and 2% for arsenic, a remarkable improvement toward the accurate detection and quantification of arsenic in contaminated waters.
- Published
- 2016
6. Nanostructured Indium Tin Oxide Slides for Small-Molecule Profiling and Imaging Mass Spectrometry of Metabolites by Surface-Assisted Laser Desorption Ionization MS
- Author
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Luis Yate, Carlos López de Laorden, Jordi Llop, Niels-Christian Reichardt, Maria Puigivila, Javier Calvo, and Ana Beloqui
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Scanning electron microscope ,Analytical chemistry ,Lactose ,Substrate (electronics) ,Microscopy, Atomic Force ,Mass spectrometry imaging ,Analytical Chemistry ,Mice ,Polysaccharides ,Ellipsometry ,Image Processing, Computer-Assisted ,Animals ,Humans ,Metabolomics ,Thin film ,Surface-assisted laser desorption/ionization ,Chemistry ,Lasers ,Photoelectron Spectroscopy ,Brain ,Tin Compounds ,Sputter deposition ,Nanostructures ,Indium tin oxide ,Milk ,Pharmaceutical Preparations ,Isotope Labeling ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,Microscopy, Electron, Scanning - Abstract
Due to their electrical conductivity and optical transparency, slides coated with a thin layer of indium tin oxide (ITO) are the standard substrate for protein imaging mass spectrometry on tissue samples by MALDI-TOF MS. We have now studied the rf magnetron sputtering deposition parameters to prepare ITO thin films on glass substrates with the required nanometric surface structure for their use in the matrix-free imaging of metabolites and small-molecule drugs, without affecting the transparency required for classical histology. The custom-made surfaces were characterized by atomic force microscopy, scanning electron microscopy, ellipsometry, UV, and laser desorption ionization MS (LDI-MS) and employed for the LDI-MS-based analysis of glycans and druglike molecules, the quantification of lactose in milk by isotopic dilution, and metabolite imaging on mouse brain tissue samples.
- Published
- 2014
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