Person: Descalzo López, Ana Belén
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First Name
Ana Belén
Last Name
Descalzo López
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Orgánica
Area
Química Orgánica
Identifiers
9 results
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Now showing 1 - 9 of 9
- Project number: 253
Item Material docente interactivo en inglés para la enseñanza práctica y el autoaprendizaje de (bio)sensores químicos ópticos en Grado y Máster(2018) Descalzo López, Ana Belén; Orellana Moraleda, Guillermo; Moreno Bondi, María Cruz; Benito Peña, María Elena; Urraca Ruiz, JavierMaterial docente (guiones de prácticas, vídeos, cuestionarios multi-respuesta) en inglés para asignaturas de Grado y Máster relacionadas con el tema de sensores (bio)químicos ópticos y la preparación de nanomateriales aplicados en sensores ópticos - Project number: 134
Item Nueva metodología de aprendizaje basado en investigación en el Laboratorio de Química Orgánica II (Grado en Química, Doble Grado en Química y Bioquímica)(2022) Illescas Martínez, Beatriz; Martínez Ruiz, María Paloma; Rodríguez Yunta, María Josefa; Gómez Aspe, Rafael; Lora Maroto, Beatriz; Martínez del Campo, Teresa; Descalzo López, Ana Belén; Santos Barahona, Jose Manuel; Cembellín Santos, Sara; Cabrera González, Justo Enrique; Patino Alonso, Jennifer; Serrano Buitrago, Sergio; Villalonga Chico, Anabel; Mayol Hornero, Beatriz; Hernández-Cornejo Pérez, JavierEste proyecto tiene como objetivo llevar a cabo un cambio conceptual del Laboratorio de Química Orgánica II, introduciendo métodos del aprendizaje mediante indagación guiada (“inquiry-guided learning”). Se ha desarrollado un aprendizaje centrado en el estudiante, que requiere que los alumnos realicen sus propias hipótesis, planifiquen su experimento, reflexionen y tomen decisiones durante el desarrollo de cada sesión. Se han utilizado como estrategias principales: 1) Diseño de una práctica piloto basada en los conceptos del aprendizaje mediante indagación guiada. Dicha práctica es diferente para cada alumno, lo que ha supuesto contar con una reserva de 12-15 prácticas diferentes previamente ensayadas. 2) Diseño y elaboración del material de laboratorio necesario para transformar las prácticas ya existentes en formato expositivo en experimentos basados en indagación, planteando preguntas que los alumnos deben responder a lo largo del experimento, sin proporcionarles previamente los resultados esperados, sino promoviendo un aprendizaje activo que integra los nuevos conceptos inferidos a partir de un verdadero proceso de experimentación e investigación. 3) Promover la discusión científica de los resultados introduciendo al final de la sesión una puesta en común con un alto componente de evaluación entre iguales (“peer-assessment”). 4) Con el fin de tutorizar el papel del profesor en este modelo de aprendizaje, se ha desarrollado una guía de ayuda al profesor. 5) Por último, se han realizado encuestas de evaluación para recibir la retroalimentación necesaria de los profesores y alumnos que se han enfrentado a esta nueva metodología en nuestro Departamento. - Project number: 307
Item La “indagación guiada” en el Laboratorio de Química Orgánica II (Grado en Química, Doble Grado en Química y Bioquímica)(2023) Illescar Martínez, Beatriz María; Martínez Ruiz, Mª Paloma; Rodríguez Yunta, Mª Josefa; Gómez Aspe, Rafael; Lora Maroto, Beatriz; Luna Costales, Amparo; Descalzo López, Ana Belén; Vázquez Rodríguez, Henar; Santos Barahona, José; Cembellín Santos, Sara; Cabrera González, Justo Enrique; Patino Alonso, Jennifer; Serrano Buitrago, Sergio; Foronda Sainz, Román; Nieto Ortiz, Gema Isabel; García Matesanz, Diego; López Zazo, Ruth; García Escobar, Mª Eugenia; Calderón Saturio, DeliaEl objetivo del proyecto es introducir la indagación guiada en el Laboratorio de Química Orgánica II. Supone la modificación de las prácticas, elaboración del material docente y creación de una sesión de búsqueda bibliográfica online. Item Highly fluorescent magnetic nanobeads with a remarkable stokes shift as labels for enhanced detection in immunoassays(Small, 2018) Salis, Francesca; Descalzo López, Ana Belén; Benito Peña, María Elena; Moreno Bondi, María Cruz; Orellana Moraleda, GuillermoFluorescence immunoassays are popular for achieving high sensitivity, but they display limitations in biological samples due to strong absorption of light, background fluorescence from matrix components, or light scattering by the biomacromolecules. A powerful strategy to overcome these problems is introduced here by using fluorescent magnetic nanobeads doped with two boron-dipyrromethane dyes displaying intense emission in the visible and near-infrared regions, respectively. Careful matching of the emission and absorption features of the dopants leads to a virtual Stokes shift larger than 150 nm achieved by an intraparticle Förster resonance energy transfer (FRET) process between the donor and the acceptor dyes. Additionally, the magnetic properties of the fluorescent beads allow preconcentration of the sample. To illustrate the usefulness of this approach to increase the sensitivity of fluorescence immunoassays, the novel nanoparticles are employed as labels for quantification of the widely used Tacrolimus (FK506) immunosuppressive drug. The FRET-based competitive inhibition immunoassay yields a limit of detection (LOD) of 0.08 ng/mL, with a dynamic range (DR) of 0.15–2.0 ng/mL, compared to a LOD of 2.7 ng/mL and a DR between 4.1 and 130 ng/mL for the immunoassay carried out with direct excitation of the acceptor dye.Item Sensitive rapid fluorescence polarization immunoassay for free mycophenolic acid determination in human serum and plasma(Analytical Chemistry, 2018) Glahn Martínez, Ana Bettina; Benito Peña, María Elena; Salis, Francesca; Descalzo López, Ana Belén; Orellana Moraleda, Guillermo; Moreno Bondi, María CruzIn this Article, we describe a fluorescence polarization immunoassay (FPIA) using a new label-near infrared fluorescent dye. The developed FPIA method was optimized for the rapid analysis of free mycophenolic acid (MPA) in plasma of transplanted patients. The approach is based on the fluorescence competitive assay between the target immunosuppressant and a novel emissive near-infrared fluorescent dye-tagged MPA and MPA-AO for the binding sites of the anti-MPA antibody. The fluorescent analogue of MPA exhibits emission at 654 nm upon excitation at 629 nm (λexcmax) and shows a good photochemical stability and a significant emission quantum yield (0.16) in phosphate buffer media. Free mycophenolic acid was isolated from blood or plasma samples using ultrafiltration prior to analysis. The sample was incubated for 20 min with 5 μg/mL of anti-MPA antibody and 1 nM of MPA-AO before the measurements. The developed FPIA displays a limit of detection of 0.8 ng/mL (10% binding inhibition) and a dynamic range of 1.7−39 ng/mL (20%−80% binding inhibition) in a PBST buffer, fitting the therapeutic requirements. The immunoassay selectivity was evaluated by measuring the cross-reactivity to other immunosuppressive drugs administered in combination with MPA (cyclosporin A and tacrolimus), as well as for the metabolite MPA glucuronide. The assay has been successfully applied to the analysis of free MPA in the blood of a heart-transplanted patient after oral administration of both mycophenolate mofetil (MMF) and tacrolimus, and the results have been compared with those obtained by rapid-resolution liquid chromatography with diode array detection (RRLC-DAD).Item Eu(III)-Templated molecularly imprinted polymer used as a luminescent sensor for the determination of tenuazonic acid mycotoxin in food samples(Sensors and Actuators B: Chemical, 2021) Rico Yuste, Alberto; Abouhany, Rahma; Urraca Ruiz, Javier; Descalzo López, Ana Belén; Orellana Moraleda, Guillermo; Moreno Bondi, María CruzTenuazonic acid (TeA) is a common mycotoxin produced by Alternaria species found in various foodstuffs. Herein, we describe the preparation of porous molecularly imprinted polymer (MIP) microspheres doped with Eu(III), for selective fast analysis of TeA in rice extracts. The TeA template, bearing a β-diketone moiety, is a good Eu(III)-chelating antenna ligand that can be selectively captured in the MIP cavities and detected by observing the “turned-on” sensitized luminescence of the Eu(III) ions at 615 nm (λex 337 nm). A MIP library was prepared at small scale using diethyl allylmalonate (DEAM) or allyl acetoacetate as functional monomers, mixed in different mole ratios with the template and ethylene glycol dimethacrylate (EDMA) as cross-linker. The screening allowed selection of poly(DEAM-co-EDMA) with Eu(III) as luminogenic metal center for the sensor development. Under the optimized conditions, a linear response to TeA in the 1.7–20 μg mL−1 range, with a detection limit of 0.5 μg mL−1, was obtained. The Eu(III)-doped MIP for TeA showed very little or no cross-recognition of other mycotoxins present in foodstuff such as alternariol, β-zearalenol and cyclopiazonic acid, even containing the same recognition moiety. The MIP-based optosensor was successfully applied to the analysis of rice extracts spiked with TeA, and the results were confirmed by HPLC-DAD.Item Interaction of a 1,3-Dicarbonyl Toxin with Ru(II)-Biimidazole Complexes for Luminescence Sensing: A Spectroscopic and Photochemical Experimental Study Rationalized by Time-Dependent Density Functional Theory Calculations(Inorganic Chemistry, 2022) Quílez Alburquerque, José; García-Iriepa, Cristina; Marazzi, Marco; Descalzo López, Ana Belén; Orellana Moraleda, GuillermoA family of ruthenium(II) complexes containing one 2,2′-biimidazole (bim) ligand and two polypyridyl (NN) ligands has been prepared and their photophysical and photochemical features have been tested in the presence of tenuazonic acid (TeA), a widespread food and feed mycotoxin of current concern. While not tested in in vivo studies, TeA and other secondary metabolites of Alternaria fungi are suspected to exert adverse effects on the human health, so sensors and rapid analytical procedures are required. It is well-known that 1,3-dicarbonyl compounds such as TeA are relatively easy to deprotonate (the pKa of TeA is 3.5), yielding an enolate anion stabilized by resonance. The chelating and hydrogen-donor features of bim allow simultaneous binding to the metal core and to the target β-diketonate delocalized anion. Such a binding induces changes in the blue absorption (40 nm bathochromic shift), red luminescence intensity (>75% quenching), and triplet lifetime (0.2 μs decrease) of the Ru(NN)2(bim)2+ luminophore. Moreover, we have computationally rationalized, by time-dependent density functional theory, the structure of the different adducts of Ru–bim complexes with TeA and the electronic nature of the spectral absorption bands and their change upon the addition of TeA.Item On the Aggregation Behaviour and Spectroscopic Properties of Alkylated and Annelated Boron-Dipyrromethene (BODIPY) Dyes in Aqueous Solution(ChemPhotoChem, 2020) Descalzo López, Ana Belén; Ashokkumar, Pichandi; Shen, Zhen; Rurack, KnutThe tendency of boron-dipyrromethene (BODIPY) dyes to associate in water is well known, and usually a cause for inferior fluorescence properties. Synthetic efforts to chemically improve BODIPYs’ water solubility and minimize this problem have been numerous in the past. However, a deeper understanding of the phenomena responsible for fluorescence quenching is still required. Commonly, the spectroscopic behaviour in aqueous media has been attributed to aggregate or excimer formation, with such works often centring on a single BODIPY family. Herein, we provide an integrating discussion including very diverse types of BODIPY dyes. Our studies revealed that even subtle structural changes can distinctly affect the association behaviour of the fluorophores in water, involving different photophysical processes. The palette of behaviour found ranges from unperturbed emission, to the formation of H or J aggregates and excimers, to the involvement of tightly bound, pre-formed excimers. These results are a first step to a more generalized understanding of spectroscopic properties vs. structure, facilitating future molecular design of BODIPYs, especially as probes for biological applications.Item Influence of the meso-substituent on strongly red emitting phenanthrene-fused boron–dipyrromethene (BODIPY) fluorophores with a propeller-like conformation.(Journal of Photochemistry and Photobiology A: Chemistry, 2018) Descalzo López, Ana Belén; Xub, Hai-Jun; Shen, Zhen; Rurack, KnutHighly emissive phenanthrene-fused boron–dipyrromethene (PBDP) dyes have been spectroscopically characterized in a series of solvents. The influence of different substituents (−H, −I, −CN, −DMA or a 15C5-crown ether) in the para-position of a phenyl ring attached to the meso-position of the BODIPY core is discussed. This family of dyes has an intense emission at λ ≥ 630 nm, with fluorescence quantum yields between 0.7 and 1.0 in all solvents studied, except in the case of the dimethylamino-substituted derivative, PBDP-DMA, which undergoes excited-state intramolecular charge transfer (CT), leading to broadband dual fluorescence in highly polar solvents. Introduction of a weaker electron donor such as a benzocrown to the meso-position is not able to trigger a second (charge or electron transfer) process and, interestingly, heavy atom (iodine, PBDP-I derivative) substitution at that moiety does also not have a relevant influence on the photophysics, i.e., enhanced intersystem crossing was not observed. Electrochemical studies of PBDP-DMA complement the data reported and stress the fact that the decrease in fluorescence of PBDP-DMA in highly polar solvents is due to an excited-state CT process rather than to a photoinduced electron transfer (PET).