Person: González Cortés, Araceli
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First Name
Araceli
Last Name
González Cortés
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Analítica
Area
Química Analítica
Identifiers
31 results
Search Results
Now showing 1 - 10 of 31
Item Electrochemical immunosensor for simultaneous determination of interleukin-1 beta and tumor necrosis factor alpha in serum and saliva using dual screen printed electrodes modified with functionalized double–walled carbon nanotubes(Analytica Chimica Acta, 2016) Sánchez Tirado, Esther; Salvo, Coral; González Cortés, Araceli; Yáñez Sedeño, Paloma; Langa, Fernando; Pingarrón Carrazón, José ManuelDual screen-printed carbon electrodes modified with 4-carboxyphenyl-functionalized double-walled carbon nanotubes (HOOC-Phe-DWCNTs/SPCEs) have been used as scaffolds for the preparation of electrochemical immunosensors for the simultaneous determination of the cytokines Interleukin-1b (IL-1b) and factor necrosis tumor a (TNF-a). IL-1b. Capture antibodies were immobilized onto HOOC-Phe DWCNTs/SPCEs in an oriented form making using the commercial polymeric coating Mix&Go™. Sandwich type immunoassays with amperometric signal amplification through the use of poly-HRPstreptavidin conjugates and H2O2 as HRP substrate and hydroquinone as redox mediator were implemented. Upon optimization of the experimental variables affecting the immunosensor performance, the dual immunosensor allows ranges of linearity extending between 0.5 and 100 pg/mL and from 1 to 200 pg/mL for IL-1b and TNF-a, respectively, these ranges being adequate for the determination of the cytokines in clinical samples. The achieved limits of detection were 0.38 pg/mL (IL-1b) and 0.85 pg/mL (TNF-a). In addition, the dual immunosensor exhibits excellent reproducibility of the measurements, storage stability of the anti-IL-Phe-DWCNTs/SPCE and anti-TNF-Phe-DWCNTs/SPCE conjugates, and selectivity as well as negligible cross-talking. The dual immunosensor was applied to the simultaneous determination of IL-1b and TNF-a in human serum spiked at clinically relevant concentration levels and in real saliva samples.Item Determinación de plastificantes y antioxidantes mediante técnicas electroanalíticas en sistemas dispersos(1994) González Cortés, Araceli; Pingarrón Carrazón, José Manuel; Yáñez-Sedeño Orive, PalomaSe ha realizado un estudio electroanalítico de los plastificantes: ftalato de dimetilo, de dietilo y de dibutilo, asi como de los antioxidantes 2-t-butil-4-metoxifenol (bha) y t-butihidroquinona (tbhq). Dada la escasa solubilidad en agua de estos aditivos, se han empleado como medios de trabajo disoluciones miscelares y emulsiones del tipo aceite-agua para desarrollar los métodos electroanalíticos. Una vez elegido el tensoactivo más adecuado para solubilizar cada analito, se han estudiado los procesos electródicos implicados, investigando el efecto del ph sobre la respuesta electroquímica y aplicando las técnicas y criterios habituales, con el fin de proponer, si ello es posible, los mecanismos de la reacción electroquímica implicada. Por último, se han establecido las características analíticas de los métodos desarrollados. En el medio emulsionado, la sistemática de trabajo ha sido análoga, si bien se ha elegido en primer lugar el disolvente orgánico adecuado para formar las emulsiones, optimizándose algunas variables experimentales de las mismas. los métodos desarrollados se han aplicado, finalmente, a la determinación de estos compuestos en muestras de alimentos, tales como leche, goma de mascar, aceites y palomitas de maíz, obteniéndose, en general, una mayor simplicidad en los procedimientos de preparación y tratamiento de la muestra debida a las características inherentes a los medios organizados empleados.Item Copper(I)-Catalyzed Click Chemistry as a Tool for the Functionalization of Nanomaterials and the Preparation of Electrochemical (Bio)Sensors(Sensors, 2019) Yáñez Sedeño, Paloma; González Cortés, Araceli; Campuzano Ruiz, Susana; Pingarrón Carrazón, José ManuelProper functionalization of electrode surfaces and/or nanomaterials plays a crucial role in the preparation of electrochemical (bio)sensors and their resulting performance. In this context, copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) has been demonstrated to be a powerful strategy due to the high yields achieved, absence of by-products and moderate conditions required both in aqueous medium and under physiological conditions. This particular chemistry offers great potential to functionalize a wide variety of electrode surfaces, nanomaterials, metallophthalocyanines (MPcs) and polymers, thus providing electrochemical platforms with improved electrocatalytic ability and allowing the stable, reproducible and functional integration of a wide range of nanomaterials and/or different biomolecules (enzymes, antibodies, nucleic acids and peptides). Considering the rapid progress in the field, and the potential of this technology, this review paper outlines the unique features imparted by this particular reaction in the development of electrochemical sensors through the discussion of representative examples of the methods mainly reported over the last five years. Special attention has been paid to electrochemical (bio)sensors prepared using nanomaterials and applied to the determination of relevant analytes at different molecular levels. Current challenges and future directions in this field are also briefly pointed out.Item Elaboración de una biblioteca audiovisual para la enseñanza de la Química Analítica(III jornada Campus Virtual UCM : Innovación en el Campus Virtual metodologías y herramientas, 2007) Moreno Bondi, María Cruz; Palacios Corvillo , María Antonia; Pérez Conde , Concepción; Gutiérrez Carreras , Ana María; Manuel de Villena Rueda , Francisco Javier; Pedrero Muñoz , María; González Cortés, Araceli; Agüí Chicharro , María Lourdes; Rodríguez Marchán, A. I.; Rosende Novo, A.; Fernández-Valmayor Crespo, Alfredo; Fernández-Pampillón Cesteros, Ana María; Merino Granizo, JorgeEl Producto Final elaborado en este proyecto forma parte de una biblioteca audiovisual que recogerá los aspectos básicos de las enseñanzas prácticas impartidas en Química Analítica en la Licenciatura en Ciencias Químicas y en Ingeniería Química. Se trata de reforzar la labor docente del Departamento y facilitar así la enseñanza del alumno en esta disciplina.Item Electrochemical immunosensor for sensitive determination of transforming growth factor (TGF) - β1 in urine(Biosensors and Bioelectronics, 2017) Sánchez Tirado, E.; Martínez García, G.; González Cortés, Araceli; Yáñez Sedeño, Paloma; Pingarrón Carrazón, José ManuelThe first amperometric immunosensor for the quantification of TGF-β1, a cytokine proposed as a biomarker for patients having or at risk for renal disease, is described in this work. The immunosensor design involves disposable devices using carboxylic acid-functionalized magnetic microparticles supported onto screen-printed carbon electrodes and covalent immobilization of the specific antibody for TGF-β1 using Mix&Go polymer. A sandwich-type immunoassay was performed using biotin-anti-TGF and conjugation with peroxidase-labeled streptavidin (poly-HRP-Strept) polymer. Amperometric measurements were carried out at 0.20 V by adding hydrogen peroxide solution onto the electrode surface in the presence of hydroquinone as the redox mediator. The calibration plot allowed a range of linearity extending between 15 and 3000 pg/mL TGF-β1 which is adequate for the determination of the cytokine in plasma and urine. The limit of detection, 10 pg/mL, is notably improved with respect to those obtained with ELISA kits. The usefulness of the immunosensor for the determination of low TGF-β1 concentrations in real samples was evaluated by analyzing spiked urine at different pg/mL concentration levels.Item Electrochemical immunosensor for sensitive determination of transforming growth factor (TGF) - β1 in urine(Biosensors and Bioelectronics, 2017) Sánchez Tirado, Esther; Martínez García, Gonzalo; González Cortés, Araceli; Yáñez Sedeño, Paloma; Pingarrón Carrazón, José ManuelThe first amperometric immunosensor for the quantification of TGF-β1, a cytokine proposed as a biomarker for patients having or at risk for renal disease, is described in this work. The immunosensor design involves disposable devices using carboxylic acid-functionalized magnetic microparticles supported onto screen-printed carbon electrodes and covalent immobilization of the specific antibody for TGF-β1 using Mix&Go polymer. A sandwich-type immunoassay was performed using biotin-anti-TGF and conjugation with peroxidase-labeled streptavidin (poly-HRP-Strept) polymer. Amperometric measurements were carried out at 0.20 V by adding hydrogen peroxide solution onto the electrode surface in the presence of hydroquinone as the redox mediator. The calibration plot allowed a range of linearity extending between 15 and 3000 pg/mL TGF-β1 which is adequate for the determination of the cytokine in plasma and urine. The limit of detection, 10 pg/mL, is notably improved with respect to those obtained with ELISA kits. The usefulness of the immunosensor for the determination of low TGF-β1 concentrations in real samples was evaluated by analyzing spiked urine at different pg/mL concentration levels.Item Viologen-functionalized single-walled carbon nanotubes as carrier nanotags for electrochemical immunosensing. Application to TGF-β1 cytokine(Biosensors and Biolelectrics, 2017) Sánchez Tirado, Esther; Arellano, Luis M.; González Cortés, Araceli; Yáñez Sedeño, Paloma; Langa, Fernando; Pingarrón Carrazón, José ManuelViologen-SWCNT hybrids are synthesized by aryl-diazonium chemistry in the presence of isoamyl nitrite followed by condensation reaction of the resulting HOOC-PheSWCNT with 1-(3-aminoethyl)-4,4’-bipyridinium bromine and N-alkylation with 2- bromoethylamine. The V-Phe-SWCNT hybrids were characterized by using different spectroscopic techniques (FT-IR, Raman, UV-vis), TGA and Kaiser test. ViologenSWCNTs were used for the preparation of an electrochemical immunosensor for the determination of the transforming growth factor β1 (TGF-β1) cytokine considered as a reliable biomarker in several human diseases. The methodology involved preparation of VPhe-SWCNT(-HRP)-anti-TGF conjugates by covalent linkage of HRP and anti-TGF onto V-Phe-SWCNT hybrids. Biotinylated anti-TGF antibodies were immobilized onto 4- carboxyphenyl-functionalized SPCEs modified with streptavidin and a sandwich type 2 immunoassay was implemented for TGF-β1 with signal amplification using V-PheSWCNT(-HRP)-anti-TGF conjugates as carrier tags. The analytical characteristics exhibited by the as prepared immunosensor (range of linearity between 2.5 and 1000 pg mL-1 TGF-β1; detection limit of 0.95 pg mL-1 ) improve notably those reported with other previous immunosensors or ELISA kits. A great selectivity against other proteins was also found. The prepared immunosensor was validated by determining TGF-β1 in real saliva samples. Minimal sample treatment was required and the obtained results were in excellent agreement with those obtained by using a commercial ELISA kit.Item Development of an Electrochemical CCL5 Chemokine Immunoplatform for Rapid Diagnosis of Multiple Sclerosis(Biosensors, 2022) Guerrero Irigoyen, Sara; Sánchez Tirado, Esther; Agüí Chicharro, María Lourdes; González Cortés, Araceli; Yáñez-Sedeño Orive, Paloma; Pingarrón Carrazón, José ManuelSerum level of CCL5 chemokine is considered an emerging biomarker for multiple sclerosis (MS). Due to the lack of specific assays for this disease, the development of a point-of-care test for rapid detection of MS could lead to avoiding diagnostics delays. In this paper, we report the first electrochemical immunoplatform for quantification of the CCL5 biomarker at the clinically required levels, able to discriminate between patients diagnosed with MS and healthy individuals. The immunosensing device involves protein capture from biological samples by complexation with biotinylated specific antibodies immobilized onto neutravidin-functionalized microparticles and sandwich assay with anti-CCL5 antibody and IgG labelled with horseradish peroxidase (HRP) for the enzyme-catalyzed amperometric detection of H2O2 using hydroquinone (HQ) as the redox mediator. The method shows excellent analytical performance for clinical application with a wide linear range of concentrations (0.1–300 ng·mL−1 CCL5, R2 = 0.998) and a low detection limit (40 pg·mL−1 CCL5). The biosensing platform was applied to the determination of the CCL5 endogenous content in 100-fold diluted sera both from healthy individuals and patients diagnosed with MS, with no further sample treatment in just two hours. The results were successfully compared with those obtained by the ELISA methodology.Item Carbon nanotubes functionalized by click chemistry as scaffolds for the preparation of electrochemical immunosensors. Application to the determination of TGF-beta 1 cytokine(Analyst, 2016) Sánchez Tirado, Esther; González Cortés, Araceli; Yáñez Sedeño, Paloma; Pingarrón Carrazón, José ManuelAn electrochemical immunosensor for the determination of the multifunctional Transforming Growth Factor β1 (TGF-β1) cytokine has been prepared using multi-walled carbon nanotube (MWCNT)-modified screen-printed carbon electrodes. MWCNTs were functionalized by means of copper(i) catalyzed azide-alkyne cycloaddition ("click" chemistry) as an efficient strategy for the covalent immobilization of immunoreagents without altering their configurations and preserving their biological activity. Alkyne-functionalized IgGs were also prepared and used to assemble IgG-alkyne-azide-MWCNT conjugates used as scaffolds for the immunosensor preparation. After a blocking step with casein, anti-TGF was immobilized and the target cytokine was sandwiched with biotinylated anti-TGF labeled with poly-HRP-labeled streptavidin. The affinity reaction was monitored amperometrically at -0.20 V using the hydroquinone (HQ)/H2O2 system. The calibration plot for TGF-β1 exhibited a range of linearity (r2 = 0.995) extending between 5 and 200 pg mL-1 which is suitable for the determination of the target cytokine in human serum. A limit of detection of 1.3 pg mL-1 was achieved. The analytical performance of the immunosensor can be advantageously compared with that claimed for ELISA kits. The immunosensor was applied to the analysis of spiked human serum samples at different concentration levels with excellent recoveries.Item Ultrasensitive detection of adrenocorticotropin hormone (ACTH) using disposable phenylboronic-modified electrochemical immunosensors(Biosensors and Bioelectronics, 2012) Moreno Guzmán, María; Ojeda, Irene; Villalonga, Reynaldo; González Cortés, Araceli; Yáñez Sedeño, Paloma; Pingarrón Carrazón, José ManuelThis work reports for the first time an electrochemical immunosensor for the determination of adrenocorticotropin hormone (ACTH). The immunoelectrode design involves the use of amino phenylboronic acid for the oriented immobilization of anti-ACTH antibodies onto screen-printed carbon modified electrode surfaces. A competitive immunoassay between the antigen and the biotinylated hormone for the binding sites of the immobilized antibody was performed. The electroanalytical response was generated by using alkaline phosphatase-labelled streptavidin and 1-naphtyl phosphate as the enzyme substrate. The electrochemical oxidation of the enzyme reaction product, 1-naphtol, measured by differential pulse voltammetry was employed to monitor the affinity reaction. Under the optimized working conditions, an extremely low detection limit of 18 pg/L was obtained. Cross-reactivity was evaluated against other hormones (cortisol, estradiol, testosterone, progesterone, hGH and prolactin) and the obtained results demonstrated an excellent selectivity. The developed immunosensor was applied to a human serum sample containing a certified amount of ACTH with good results.