Browsing by Subject "NANOPARTICULAS"
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artículo de publicación periódica.listelement.badge Carbohydrate-derived polytriazole nanoparticles enhance the antiInflammatory activity of cilostazol(2022-11-30) Rivas, M. Verónica; Musikant, Daniel; Díaz Peña, Rocío; Álvarez, Daniela; Pelazzo, Luciana; Rossi, Ezequiel; Martínez, Karina D.; Errea, María Inés; Pérez, Óscar E.; Varela, Óscar; Kolender, Adriana K."Poly(amide-triazole) and poly(ester-triazole) synthesized from d-galactose as a renewable resource were applied for the synthesis of nanoparticles (NPs) by the emulsification/solvent evaporation method. The NPs were characterized as stable, spherical particles, and none of their components, including the stabilizer poly(vinyl alcohol), were cytotoxic for normal rat kidney cells. These NPs proved to be useful for the efficient encapsulation of cilostazol (CLZ), an antiplatelet and vasodilator drug currently used for the treatment of intermittent claudication, which is associated with undesired side-effects. In this context, the nanoencapsulation of CLZ was expected to improve its therapeutic administration. The carbohydrate-derived polymeric NPs were designed taking into account that the triazole rings of the polymer backbone could have attractive interactions with the tetrazole ring of CLZ. The activity of the nanoencapsulated CLZ was measured using a matrix metalloproteinase model in a lipopolysaccharide-induced inflammation system. Interestingly, the encapsulated drug exhibited enhanced anti-inflammatory activity in comparison with the free drug. The results are very promising since the stable, noncytotoxic NP systems efficiently reduced the inflammation response at low CLZ doses. In summary, the NPs were obtained through an innovative methodology that combines a carbohydrate-derived synthetic polymer, designed to interact with the drug, ease of preparation, adequate biological performance, and environmentally friendly production."proyecto final de grado.listelement.badge Diseño y fabricación de un sistema de transporte controlado de nanopartículas superparamagnéticas para su integración a un biosensor(2020) Altamirano Carlavan, María Agustina; Mosquera, Valeria; Notcovich, Cintia; Berlín, Guillermo Luis"El trabajo presenta el diseño, la fabricación y la caracterización de un sistema de transporte controlado de nanopartículas superparamagnéticas (NPM) que se fundamenta en el uso de los campos magnéticos resultantes de la circulación de corrientes eléctricas. Se concibe con el objetivo de ser integrado a un sistema de diagnóstico del Síndrome Urémico Hemolítico (SUH) que utiliza NPM funcionalizadas con anticuerpos capaces de unirse específicamente a la bacteria causante del mismo. El proyecto Micromaglab (MAGLAB) está actualmente desarrollando este dispositivo de tipo Lab-on-a-Chip (LoC) en el Departamento de Micro y Nanotecnología del Centro Atómico Constituyentes (CAC) perteneciente a la Comisión Nacional de Energía Atómica (CNEA)."artículo de publicación periódica.listelement.badge Enhanced retention of bacteria by TiO2 nanoparticles in saturated porous media(2016-08) Gentile, Guillermina José; Fidalgo de Cortalezzi, María Marta"The simultaneous transport of TiO2 nanoparticles and bacteria Pseudomonas aeruginosa in saturated porous media was investigated. Nanoparticle and bacterium size and surface charge were measured as a function of electrolyte concentration. Sand column breakthrough curves were obtained for single and combined suspensions, at four different ionic strengths. DLVO and classical filtration theories were employed to model the interactions between particles and between particles and sand grains. Attachment of TiO2 to the sand was explained by electrostatic forces and these nanoparticles acted as bonds between the bacteria and the sand, leading to retention. Presence of TiO2 significantly increased the retention of bacteria in the sand bed, but microorganisms were released when nanomaterial influx ceased. The inclusion of nanomaterials in saturated porous media may have implications for the design and operation of sand filters in water treatment."ponencia en congreso.listelement.badge Estudio de la influencia de fuerza iónica, pH y materia orgánica natural en la agregación de nanopartículas de dióxido de titanio(2019-08) Barboni, Tomás; Devoli Díaz, Juan Gabriel; Mujica, Clara; Peralta, Mateo; Gentile, Guillermina José"El objetivo general del presente trabajo fue investigar cómo la agregación de las nanopartículas de dióxido de titanio (TiO2) y su carga de superficie, son influenciadas por el pH, la fuerza iónica y la presencia de materia orgánica natural (MON). Los resultados obtenidos evidenciaron que las nanopartículas de TiO2 sufren un rápido proceso de agregación y en ningún caso fue posible tenerlas en su tamaño primario de 21 nm. Dentro de los resultados más relevantes, se puede mencionar que la influencia de los iones divalentes, como el Ca2+, así como elevados valores de fuerza iónica, 10 mM, tuvieron un gran aporte en la desestabilización de las nanopartículas. La influencia del pH se vio muy marcada en las suspensiones donde había solamente iones indiferentes y en baja concentración. En todos los casos, la adición de MON provocó una gran disminución de los valores de potencial zeta, obteniéndose valores muy negativos y, en consecuencia, se logró aumentar notablemente la estabilidad de las nanopartículas. La forma y estructura de los agregados, así como su tamaño y el de las partículas primarias se pudo también observar por medio de microscopía electrónica de barrido (SEM)."artículo de publicación periódica.listelement.badge Evaluation of silicone fluids and resins as CO2 thickeners for enhanced oil recovery using a computational and experimental approach(2021-09) Gallo Jiménez, Gonzalo Augusto; Erdmann, Eleonora; Cavasotto, Claudio N."CO2 thickeners have the potential to be a game changer for enhanced oil recovery, carbon capture utilization and storage, and hydraulic fracturing. Thickener design is challenging due to polymers’ low solubility in supercritical CO2(scCO2) and the difficulty of substantially increasing the viscosity of CO2. In this contribution, we present a framework to design CO2 soluble thickeners, combining calculations using a quantum mechanical solvation model with direct laboratory viscosity testing. The conductor-like polarizable continuum model for solvation free-energy calculations was used to determine functional silicone and silsesquioxane solubilities in scCO2. This method allowed for a fast and efficient identification of CO2-soluble compounds, revealing silsesquioxanes as more CO2-philic than linear polydimethylsiloxane (PDMS), the most efficient non-fluorinated thickener know to date. The rolling ball apparatus was used to measure the viscosity of scCO2 with both PDMS and silicone resins with added silica nanoparticles. Methyl silicone resins were found to be stable and fast to disperse in scCO2 while having a significant thickening effect. They have a larger effect on the solution viscosity than higher-molecular-weight PDMS and are able to thicken CO2 even at high temperatures. Silicone resins are thus shown to be promising scCO2 thickeners, exhibiting enhanced solubility and good rheological properties, while also having a moderate cost and being easily commercially attainable."artículo de publicación periódica.listelement.badge Interparticle effects in the cotransport of viruses and engineered nanoparticles in saturated porous media(2021-10) Gentile, Guillermina José; Blanco Fernández, María Dolores; Fidalgo de Cortalezzi, María Marta"The effects of P25 TiO2 nanoparticles on the transport in saturated porous media of the bacteriophage PP7 was investigated. Two levels of ionic strength were considered, given by monovalent and divalent cations, Na+ and Ca2+. The viruses and the P25 particles were characterized with respect to size and surface charge, by dynamic light scattering and electron microscopy. The breakthrough curves were obtained for suspensions of each particle and both combined, using UV absorbance to quantify P25 and RT-qPCR for PP7. In the single transport experiments, P25 was retained, while the viruses mostly eluted the sand bed. However, in the cotransport experiments, retention increased for the virus and decreased for the TiO2 nanoparticles under high viral content, due to heteroaggregation among the colloids in the incoming suspension, electrostatic interactions, and ripening. The interparticle interactions were modeled by DLVO theory, resulting in agreement with the experimental observations, which highlights the electrostatic nature."tesis de doctorado.listelement.badge Surface phenomena affecting the transport and removal of viruses and bacteria in natural and engineered porous media: implications for water quality(2016-06) Gentile, Guillermina José; Fidalgo de Cortalezzi, María Marta; Errea, María Inés"El objetivo general de la tesis fue profundizar el conocimiento de las interacciones presentes en las interfases entre superficies, microorganismos y nanomateriales en medios acuosos. En particular se estudiaron las interacciones en tres sistemas diferentes: transporte de microorganismos y nanopartículas a través de lechos porosos, eliminación en sistemas acuosos de bacteriófagos modelo por medio de membranas cerámicas nanoestructuradas, y membranas empleadas en ultrafiltración de aguas para la remoción de bacteriófagos como modelo de virus patógenos. Los resultados obtenidos podrán ser de utilidad para elaborar mejoras en los procesos estudiados con fines de asegurar la calidad del agua. Adicionalmente, se analizó la factibilidad de la aplicación de membranas en el proceso de ósmosis retardada por presión (PRO) para generación de energía eléctrica en el país."artículo de publicación periódica.listelement.badge Virus removal by iron oxide ceramic membranes(2014-09) Fidalgo de Cortalezzi, María Marta; Gallardo, María V.; Yrazu, Fernando M.; Gentile, Guillermina José; Opezzo, Oscar; Pizarro, Ramón A.; Poma, Hugo R.; Rajal, Verónica Beatriz"Nanoporous iron oxide ceramics were studied for the removal of virus contamination from water. Supported and unsupported iron oxide nanostructured hematite was fabricated by a green chemistry route from ferroxane nanoparticles. The material had a surface area of approximately 30 m2/g and a mean pore size of 65 nm. Bacteriophage P22 was chosen as a model for human virus. The kinetics and equilibrium of the attachment process was investigated. P22 adsorption isotherms on iron oxide were described by the Freundlich equation. Batch experiments resulted in 1.5 LRVs. Removal proceeded rapidly for the first 7 h; next, a diffusion-limited stage occurred. Dynamic attachment experiments demanded extensive recirculation to achieve significant reduction levels. Up to 3 LRV were observed. The enhanced performance can be explained by the higher iron oxide area available and the facilitated access to inner porosity sites that were previously unavailable due to slow diffusion. The role of electrostatic interactions in the attachment mechanisms was confirmed by the dependence of the isotherm on the ionic strength of the suspension medium. P22 bacteriophage is expected to attach to the iron oxide by electrostatic forces up to a pH of 6.5. DLVO theory predicts moderately well the interaction energies between P22 particles themselves and between the phage and the ceramic. However, a slight underestimation of the P22–P22 repulsive forces was evident by comparison to the experimental data."