Determinación de plastificantes y antioxidantes mediante técnicas electroanalíticas en sistemas dispersos

Se 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

“PROCESO DE ENFERMERÍA COMO CONSTRUCTOR DE AUTONOMÍA PROFESIONAL: UNA INVESTIGACIÓN ACCIÓN

El compromiso que tienen las y los enfermeros al centrar su objeto en el cuidado de la salud los lleva a cumplir con el reto de ejercer autonomía en la práctica, no obstante como se ha señalado anteriormente, el concepto se ha manejado de acuerdo a las perspectivas de diferentes autores, debido a que no existe una definición universal de autonomía profesional de enfermería que unifique el criterio de los profesionales. Entre los diferentes autores se han encontrado dos aspectos de la autonomía: desde la perspectiva del profesional y de la perspectiva del paciente (Kramer, 2008).Esta investigación presenta una panorámica de la construcción de la autonomía de enfermería con base al proceso de enfermería (PE); de esta manera se refleja el deber de la enfermera, para y con el paciente, de tal forma se manifiesta la transcendencia de la intervención en el campo clínico, donde la profesión tiene gran compromiso en el desarrollo del cuidado científico. Pero siempre con la visión de que a medida que la enfermera crece, el paciente se ve favorecido

Multiplexed Ultrasensitive Determination of Adrenocorticotropin and Cortisol Hormones at a Dual Electrochemical Immunosensor

A novel dual electrochemical immunosensor for the multiplexed determination of adrenocorticotropin (ACTH) and cortisol is reported. Aminophenylboronic acid-modified dual screen-printed carbon electrodes were prepared on which the corresponding ACTH and cortisol antibodies were immobilized. Competitive immunoassays involved biotinylated ACTH and alkaline phosphatase labelled streptavidin, or alkaline phosphatase labelled cortisol. Differential pulse voltammetry upon 1-naphtyl phosphate addition was employed to monitor the affinity reactions. The ranges of linearity were 5.0×10−5−0.1 and 0.1−500 ng/mL for ACTH and cortisol. The usefulness of the dual immunosensor was demonstrated by analyzing certified human serum samples with good recoveries

Biodetection Techniques for Quantification of Chemokines

Chemokines are a class of cytokine whose special properties, together with their involvement and relevant role in various diseases, make them a restricted group of biomarkers suitable for diagnosis and monitoring. Despite their importance, biodetection techniques dedicated to the selective determination of one or more chemokines are very scarce. For some years now, the critical diagnosis of inflammatory diseases by detecting both cytokine and chemokine biomarkers, has had a strong impact on the development of multiple detection platforms. However, it would be desirable to implement methodologies with a higher degree of selectivity for chemokines, in order to provide more precise information. In addition, better development of biosensor technology applied to this specific field would make it possible to address the main challenges of detection methods for several diseases with a high incidence in the population, avoiding high costs and low sensitivity. Taking this into account, this review aims to present the state of the art of chemokine biodetection techniques and emphasize the role of these systems in the prevention, monitoring and treatment of various diseases associated with chemokines as a starting point for future developments that are also analyzed throughout the article.Depto. de Química AnalíticaFac. de Ciencias QuímicasTRUEMinisterio de Ciencia, Innovación y UniversidadesComunidad de Madridpu

Electrochemical Magnetic Immunosensors for the Determination of Ceruloplasmin

Electrochemical immunosensors for ceruloplasmin (Cp) are reported for the first time. Two configurations involving magnetic beads (MBs) functionalized with Protein A or Streptavidin for immobilization of Cp antibodies were compared, using competitive immunoassay with synthesized alkaline phosphatase-Cp conjugate. Upon capturing MBs-immunoconjugates onto screen-printed carbon electrodes, quantification of Cp was accomplished by DPV measurement of 1-naphthol generated after 1-naphthylphosphate addition. Linear ranges of calibration curves and detection limits were 0.1–1000 µg/mL and 0.040 µg/mL (Protein A-MBs), and 0.025–20 µg/mL and 0.018 µg/mL (Strept-MBs). Good results were obtained in the determination of Cp in spiked human serum samples

Crecimiento y calidad espermática en trucha arcoíris Oncorhynchus mykiss (Teleostei: Salmonidae) durante la temporada reproductiva

Background. Oncorhynchus mykiss is a species that is widely cultivated in the world with high economic value. For this reason, it is essential to optimize its growth and reproduction for aquaculture. Goals. Evaluate the growth and sperm quality of rainbow trout during the reproductive season. Methods. We conducted research at the "El Zarco" Aquaculture Center in the state of Mexico, with 32 sexually mature three-year-old males. Once a month, we recorded total length, height, thickness (cm), and weight (g) during July-February, and calculated weight gain (WG), absolute growth rate (AGR), and instantaneous growth rate (IGR). Semen samples were obtained during (August-February). In order to evaluate the spermatic quality, we measured volume, color, consistency, concentration, pH, and mobility. Results. The highest AGR, WG, and IGR in terms of length and weight were obtained from July-August, i.e., a month prior to the reproductive period; from August-February the AGR was 1.13 cm, WG was 0.01 g, and there was an average IGR of 0.0321 ± 0.0522 cm and 0.0932 ± 0.2223 g. Differences (p <0.05) in length and weight were found between July and the months of the reproductive period. There was a pattern of semen production: It increased from August to October and then decreased until February, with significant differences (p <0.05). Usually, white semen and milky consistency were found. The highest sperm concentration occurred in September (8.17 ± 2.06 x 109 mL-1) and decreased until February, with significant differences (p <0.05) between months. The pH was alkaline with an average value of 8.07 ± 0.31. Mobility increased from August to December and decreased from January to February, with significant differences (p <0.05) between months. Conclusions. During the reproductive period, food energy is channeled to ensure reproduction, so that growth slows and sperm quality varies during the reproductive months.  Antecedentes. Oncorhynchus mykiss es una de las especies que más se cultiva en el mundo y que tiene alto valor económico, por tal motivo, optimizar su crecimiento y reproducción es fundamental para la acuacultura. Objetivos. Evaluar el crecimiento y calidad espermática en trucha arcoíris durante la temporada reproductiva. Métodos. La investigación se realizó en el centro acuícola El Zarco, Estado de México, con 32 machos sexualmente maduros de tres años. De julio a febrero se registraron mensualmente: longitud total, altura, grosor (cm), peso (g), ganancia de peso (GP), tasa de crecimiento absoluto (TCA) y tasa instantánea de crecimiento (TIC). Las muestras de semen se obtuvieron de agosto a febrero. Las variables para determinar la calidad espermática fueron: volumen, color, consistencia, concentración, pH y movilidad. Resultados. En cuando a longitud y peso, la mayor TCA, GP y TIC se obtuvo de julio a agosto, mes previo al periodo reproductivo. De agosto a febrero la TCA fue de 1.13 cm; GP de 0.01 g y TIC de 0.0321 ± 0.0522 cm y 0.0932 ± 0.2223 g en promedio. En julio se registraron diferencias en longitud y peso (p <0.05) en comparación con los meses del periodo reproductivo. El patrón de producción de semen se incrementó de agosto a octubre y decreció hasta febrero con diferencias significativas (p <0.05). En general, se encontró semen de color blanco y consistencia lechosa. La mayor concentración espermática se presentó en septiembre (8.17 ± 2.06 x 109 mL-1) y disminuyó hasta febrero, con diferencias significativas (p <0.05) entre los meses. El pH fue alcalino, con un promedio de 8.07 ± 0.31. La movilidad mostró un incremento de agosto a diciembre y un decremento de enero a febrero, con diferencias significativas (p <0.05) entre los meses. Conclusiones. Durante el periodo reproductivo la energía procedente del alimento se destina a asegurar la reproducción, por lo que el crecimiento se ralentiza y la calidad espermática varía entre los meses

Electrochemical Immunosensor for Simultaneous Determination of Emerging Autoimmune Disease Biomarkers in Human Serum †

Rheumatoid arthritis is an autoimmune disorder characterized by persistent erosive synovitis, systemic inflammation and the presence of autoantibodies, which play an important role in inducing inflammation and joint damage, releasing pro-inflammatory cytokines from monocytes and macrophages [1,2]. Likewise, neutrophil activating protein-2 (CXCL7) is a platelet-derived growth factor belonging to the CXC chemokine subfamily, which is expressed in serum, synovial fluid and synovial tissue of patients developing rheumatoid arthritis during the first twelve weeks, being useful to reflect local pathological changes [3]. Besides, matrix metalloproteinase-3 (MMP-3), which is induced by inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-α) in rheumatoid synovium, degrades several extracellular matrix components of cartilage and plays central roles in rheumatoid joint destruction [4]. Therefore, monitoring serum CXCL7 and MMP-3 levels is useful for predicting the disease activity in rheumatoid arthritis. In this work, the construction and analytical performance of a dual electrochemical platform for the simultaneous determination of CXCL7 and MMP-3 is described. After the optimization of experimental variables involved in the preparation and implementation of the biosensor, the analytical usefulness of the developed configuration was demonstrated by its application to the determination of these biomarkers in serum samples from healthy individuals and patients with rheumatoid arthritis. To carry out the simultaneous determination of CXCL7 and MMP3 in human serum, just a fifty-fold sample dilution in PBS of pH 7.4 was required. In addition, the results obtained using the dual immunosensor were compared with those provided by the respective ELISA immunoassays, yielding no significant differences between the two methods. It is important to highlight that reagents consumption, four times smaller using the dual immunosensor than that required in the ELISA protocol, and an assay time of 2 h 50 min versus almost 5 h, counted in both cases after incubation of the capture antibody, are advantageous features of the dual immunosensor [5].Depto. de Química AnalíticaFac. de Ciencias QuímicasTRUEMinisterio de Ciencia, Innovación y UniversidadesComunidad de Madridpu

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

Dual 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

Ultrasensitive detection of adrenocorticotropin hormone (ACTH) using disposable phenylboronic-modified electrochemical immunosensors

This 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

Viologen-functionalized single-walled carbon nanotubes as carrier nanotags for electrochemical immunosensing. Application to TGF-β1 cytokine

Viologen-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