Person: Rubio Retama, Benito Jorge
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First Name
Benito Jorge
Last Name
Rubio Retama
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Química en Ciencias Farmacéuticas
Area
Química Física
Identifiers
8 results
Search Results
Now showing 1 - 8 of 8
Item Enhancement of the Upconversion Emission by Visible-to-Near-Infrared Fluorescent Graphene Quantum Dots for miRNA Detection(ACS Applied Materials & Interfaces, 2016) Laurenti, Marco; Paez-Pérez, Miguel; Algarra González, Manuel; Alonso Cristobal, Paulino; López Cabarcos, Enrique; Méndez González, Diego; Rubio Retama, Benito JorgeWe developed a sensor for the detection of specific microRNA (miRNA) sequences that was based on graphene quantum dots (GQDs) and ssDNA-UCNP@SiO2. The proposed sensor exploits the interaction between the sp2 carbon atoms of the GQD, mainly π–π stacking, and the DNA nucleobases anchored on the upconversion nanoparticles (UCNPs). This interaction brings the GQD to the surface of the ssDNA-UCNP@SiO2 system, enhancing the upconversion emission. On the other hand, hybridization of the single-stranded DNA (ssDNA) chains anchored on the nanoparticles with their complementary miRNA sequences blocks the capacity of the UCNPs to interact with the GQD through π–π stacking. That gives as result a reduction of the fluorescent enhancement, which is dependent on the concentration of miRNA sequences. This effect was used to create a sensor for miRNA sequences with a detection limit of 10 fM.Item 10-Fold Quantum Yield Improvement of Ag2S Nanoparticles by Fine Compositional Tuning(ACS Applied materials and interfaces, 2020) Ortega Rodríguez, Alicia; Shen, Yingli; Zabala Gutiérrez, Irene; Santos, Harrison D. A.; Torres Vera, Vivian Andrea; Ximedes, Erving; Villaverde Cantizano, Gonzalo; Lifante, José; Gerke, Christoph; Fernández Monsalve, Nuria; Gómez Calderón, Óscar; Melle Hernández, Sonia; Marqués Hueso, José; Méndez González, Diego; Laurenti, Marco; Jones, Callum M. S.; López Romero, Juan Manuel; Contreras Cáceres, Rafael; Jaque García, Daniel; Rubio Retama, Benito Jorge; Garma Pons, SantiagoAg2S semiconductor nanoparticles (NPs) are near-infrared luminescent probes with outstanding properties (good biocompatibility, optimum spectral operation range, and easy biofunctionalization) that make them ideal probes for in vivo imaging. Ag2S NPs have, indeed, made possible amazing challenges including in vivo brain imaging and advanced diagnosis of the cardiovascular system. Despite the continuous redesign of synthesis routes, the emission quantum yield (QY) of Ag2S NPs is typically below 0.2%. This leads to a low luminescent brightness that avoids their translation into the clinics. In this work, an innovative synthetic methodology that permits a 10-fold increment in the absolute QY from 0.2 up to 2.3% is presented. Such an increment in the QY is accompanied by an enlargement of photoluminescence lifetimes from 184 to 1200 ns. The optimized synthetic route presented here is based on a fine control over both the Ag core and the Ag/S ratio within the NPs. Such control reduces the density of structural defects and decreases the nonradiative pathways. In addition, we demonstrate that the superior performance of the Ag2S NPs allows for high-contrast in vivo bioimaging. .Item Contribution of resonance energy transfer to the luminescence quenching of upconversion nanoparticles with graphene oxide(Journal of Colloid and Interface Science, 2020) Méndez González, Diego; Gómez Calderón, Óscar; Melle Hernández, Sonia; González Izquierdo, Jesús; Bañares Morcillo, Luis; López Díaz, David; Velazquez Salicio, M. Mercedes; López Cabarcos, Enrique; Rubio Retama, Benito Jorge; Laurenti, MarcoUpconversion nanoparticles (UCNP) are increasingly used due to their advantages over conventional fluorophores, and their use as resonance energy transfer (RET) donors has permitted their application as biosensors when they are combined with appropriate RET acceptors such as graphene oxide (GO). However, there is a lack of knowledge about the design and influence that GO composition produces over the quenching of these nanoparticles that in turn will define their performance as sensors. In this work, we have analysed the total quenching efficiency, as well as the actual values corresponding to the RET process between UCNPs and GO sheets with three different chemical compositions. Our findings indicate that excitation and emission absorption by GO sheets are the major contributor to the observed luminescence quenching in these systems. This challenges the general assumption that UCNPs luminescence deactivation by GO is caused by RET. Furthermore, RET efficiency has been theoretically calculated by means of a semiclassical model considering the different nonradiative energy transfer rates from each Er3+ ion to the GO thin film. These theoretical results highlight the relevance of the relative positions of the Er3+ ions inside the UCNP with respect to the GO sheet in order to explain the RET-induced efficiency measurements.Item The effects of dopant concentration and excitation intensity on the upconversion and downconversion emission processes of β-NaYF4:Yb3+,Er3+nanoparticles(Journal of materials chemistry C, 2021) Torres Vera, Vivian Andrea; Méndez González, Diego; Ramos Ramos, D. J.; Igalla El-Youssfi, Asmae; Laurenti, Marco; Contreras Cáceres, Rafael; López Cabarcos, Enrique; Díaz García, Elena; Rubio Retama, Benito Jorge; Melle Hernández, Sonia; Gómez Calderón, ÓscarThe dopant concentration of lanthanide ions in photon upconversion nanoparticles (UCNPs) remains one of the key points to boost the brightness of these nanomaterials and, therefore, their application developments. Here, we analyzed the effect of Er3+ and Yb3+ dopant concentrations of b-NaYF4:Yb3+,Er3+ nanoparticles on the visible upconversion and near-infrared downconversion luminescence intensities. Our approach carefully excluded all other factors whose variation affects luminescence properties such as the size, morphology, crystal structure, ion distribution, ligand, and surrounding medium, allowing us to exactly infer the influence of the ratio of Yb3+ to Er3+ ions on the nanoparticle luminescence. To maintain the size and morphological properties of nanoparticles, we used a total dopant concentration of 22% while varying the ratio of Yb3+ to Er3+ ions from 0 to 10. A huge increase in luminescence takes place as the Yb/Er ratio increases following a power-law behavior, and this luminescence enhancement is greater at low excitation intensities. Above a Yb/Er ratio of around two, saturation occurs with a slight peak when this ratio is around four. Simulations using a rate equation model showed that upconversion luminescence (UCL) is mainly produced by the energy transfer between neighboring Er3+ ions at low Yb/Er ratios, while at high ratios, the energy transfer from Yb3+ to Er3+ ions dominates. However, downconversion luminescence (DCL) is produced at all analyzed ratios, except 0, by the previous mechanism.- Project number: 74
Item Las TICs: un instrumento de ayuda en las prácticas de laboratorio(2022) Laurenti, Marco; Ovejero Paredes, Karina; Zabala Gutiérrez, Irene; Sanchez Sanche, Visitación; Yusta San Roman, Piedad; Contreras Cáceres, Rafael; Filice, Marco; López Cabarcos, Enrique; Marciello, Marzia; Méndez González, Diego; Rubio Retama, Benito Jorge; Villaverde Cantizano, GonzaloDesde la implantación del Espacio Europeo de Educación Superior nos encontramos ante dos grandes retos; el desarrollo metodológico y tecnológico en la formación y docencia on-line y en segundo lugar la cada vez más elevada especialización requerida a los estudiantes durante el Grado y Doble Grado en Farmacia. Esto hace que el foco de la formación de los estudiantes se desvíe de los conocimientos básicos y competencias de formación tanto en el trabajo experimental como en el conocimiento teórico. El proyecto se encuadra en el marco de la asignatura obligatoria Física Aplicada a Farmacia de Grado y Doble Grado en Farmacia, unas carreras con una elevada carga práctica y experimental. Item Multi-responsive hybrid Janus nanoparticles: Surface functionalization through solvent physisorption(European Polymer Journal, 2016) Méndez González, Diego; Alonso-Cristobal, Paulino; López Cabarcos, Enrique; Rubio Retama, Benito JorgeIn this work, we present a simple methodology to produce multi-responsive Janus nanoparticles using a Pickering emulsion-based approach. In order to use these nanoparticles (NPs) as emulsion stabilizers, tetrahydrofuran was physisorbed on the surface of freshly synthesized Fe3O4@SiO2 NPs, which reduced their inherent hydrophilic character and permitted to create a close packed arrangement of particles at the emulsion interface. This situation allowed selective functionalization of the surface of the nanoparticles exposed to the water phase with a vinyl derivate molecule, which permitted to initiate the sequential polymerization of pNIPAM and poly(vinylimidazole). Thus, we obtained Janus nanoparticles that responded to changes in the temperature and the pH of the media as well as to external magnetic fields. The presented method does not require the surface modification of the original nanoparticles with surfactants or the use of fused silica and provides an easy way to create Janus particles in the nanoscale range.Item Ion-induced bias in Ag2S luminescent nanothermometers(Nanoscale, 2023) París Ogayar, Marina; Méndez González, Diego; Zabala Gutiérrez, Irene; Artiga , Alvaro; Rubio Retama, Benito Jorge; Gómez Calderón, Óscar; Melle Hernández, Sonia; Alda Serrano, Javier; Espinosa, Ana; Jaque, Daniel; Marín Viadel, RicardoLuminescence nanothermometry allows measuring temperature remotely and in a minimally invasive way by using the luminescence signal provided by nanosized materials. This technology has allowed, for example, the determination of intracellular temperature and in vivo monitoring of thermal processes in animal models. However, in the biomedical context, this sensing technology is crippled by the presence of bias (cross-sensitivity) that reduces the reliability of the thermal readout. Bias occurs when the impact of environmental conditions different from temperature also modifies the luminescence of the nanothermometers. Several sources that cause loss of reliability have been identified, mostly related to spectral distortions due to interaction between photons and biological tissues. In this work, we unveil an unexpected source of bias induced by metal ions. Specifically, we demonstrate that the reliability of Ag2S nanothermometers is compromised during the monitoring of photothermal processes produced by iron oxide nanoparticles. The observed bias occurs due to the heat-induced release of iron ions, which interact with the surface of the Ag2S nanothermometers, enhancing their emission. The results herein reported raise a warning to the community working on luminescence nanothermometry, since they reveal that the possible sources of bias in complex biological environments, rich in molecules and ions, are more numerous than previously expected.Item Optomagnetic nanofluids for controlled brain hyperthermia: a critical study(Nanoscale, 2022) Méndez González, Diego; Lifante, José; Zabala Gutiérrez, Irene; Marin, Riccardo; Ximendes, Erving; Sanz-de Diego, Elena; Iglesias-de la Cruz, M. Carmen; Teran, Francisco J.; Rubio Retama, Benito Jorge; Jaque, DanielOptomagnetic nanofluids (OMNFs) are colloidal dispersions of nanoparticles (NPs) with combined magnetic and optical properties. They are especially appealing in biomedicine since they can be used as minimally invasive platforms for controlled hyperthermia treatment of otherwise difficultly accessible tumors such as intracranial ones. On the one hand, magnetic NPs act as heating mediators when subjected to alternating magnetic fields or light irradiation. On the other hand, suitably tailored luminescent NPs can provide a precise and remote thermal readout in real time. The combination of heating and thermometric properties allows, in principle, to precisely monitor the increase in the temperature of brain tumors up to the therapeutic level, without causing undesired collateral damage. In this work we demonstrate that this view is an oversimplification since it ignores the presence of relevant interactions between magnetic (γ-Fe2O3 nanoflowers) and luminescent nanoparticles (Ag2S NPs) that result in a detrimental alteration of their physicochemical properties. The magnitude of such interactions depends on the interparticle distance and on the surface properties of nanoparticles. Experiments performed in mouse brains (phantoms and ex vivo) revealed that OMNFs cannot induce relevant heating under alternating magnetic fields and fail to provide reliable temperature reading. In contrast, we demonstrate that the use of luminescent nanofluids (containing only Ag2S NPs acting as both photothermal agents and nanothermometers) stands out as a better alternative for thermally monitored hyperthermia treatment of brain tumors in small animal models.