Quimica Analitica

This paper shows the influence of different sample storage protocols, on the chemiluminescence signal of some metal ions. The storage protocols studied were: acid addition (HCl or HNO3) and no reagent addition to filtered and refrigerated (T_/4 8C) samples. Light emission was produced for the chemiluminescence reaction between luminol and hydrogen peroxide in buffer carbonate conditions (pH 10.8) catalysed by Cr(III), Co(II) and Cu(II). Batch and/or flow modes in different conditions were tested. Fe(II), Fe(III), Ni(II) and Mn(II) did not give chemiluminescence in the studied conditions. A parallel study of sensitivity and selectivity was performed. Then the presence or absence of the masking agent EDTA, added to samples or used in the carrier stream, is assayed. If the samples are acidified with HNO3, a previous neutralisation is needed using batch mode. The determination of Cr(III) is independent of storage protocol by flow injection (FI) method; however, the determination of Co(II) or Cu(II) or total determination of three metals requires the conditioning of standards. Detection limits achieved are ranged between 0.5 and 2 mg l_1. For batch mode, detection limits are better for unacidified samples and worse for carbonate-neutralised samples. The influence of storage protocols was validated using standard metal mixtures and calibration solutions. The use of standard reference material (SRM# 1640) (Trace elements in natural water) corroborates the previous statements and validates the accuracy of the different approaches underlined. This paper demonstrates that it is possible to determine Cr(III) selectively in natural waters.

The simultaneous determination of chromium and cobalt in water samples has been studied. Chemiluminescence registers based on the luminol-hydrogen peroxide reaction have obtained by a batch procedure. PLS algorithms have employed to model the time-response (formation and destruction of emitter). The influence of the presence of two metals and the non-linearity relationship between response and concentration have been evaluated in the signal. Different experimental designs and the selection of variables have been tested. The calibration set has been selected based on two criteria: unicomponent and/or bicomponent standard solutions and the slope calculated from linear univariate calibration. The response has been modelled providing high percentages of explained variance, robust models and low prediction errors. The proposed methodology has been validated using test standard solutions and a standard reference material of fresh water. Accurate results have proved the advantages of this method for the simultaneous determination of chromium and cobalt in water samples.

Resumo: Experimentos de cinética, isoterma e equilíbrio termodinâmico, referentes à adsorção do corante têxtil violeta 5R Remazol sobre quitosana em meio aquoso, foram estudados neste trabalho, além da caracterização do material adsorvente. Os métodos de caracterização utilizados foram: IV, TG, DR-X e MEV. As adsorções foram realizadas variando-se a concentração do corante (construção das isotermas), o tempo (testes de cinética), a temperatura (nos experimentos termodinâmicos) e o pH do meio. Os resultados de pH indicaram a melhor faixa de adsorção entre 4,0 e 6,0. A cinética reacional se baseia numa lei de pseudo-segunda ordem e a isoterma está de acordo com o modelo de Langmuir, sugerindo a quimiossorção como modelo de adsorção. Os resultados de ∆G° sempre apresentaram valores negativos nas temperaturas estudadas, indicando espontaneidade nesses processos. Já os valores positivos de ∆H° e ∆S° sugerem que a adsorção é um processo endotérmico com aumento na desordem do sistema. Palavras-chave: Quitosana. Biopolímeros. Adsorção. Corantes têxteis.

Procedimiento de obtención de particulas de ZnO con morfología acicular. 57 Resumen: Procedimiento de obtención de partículas de ZnO con morfología acicular. La presente invención utiliza el método de precipitación controlada para obtener partículas de ZnO con morfología acicular. A través del control de los parámetros de formación de precursores intermedios de compuestos de cinc y la evolución de dichos precursores intermedios mediante el lavado con agua destilada de la suspensión coloidal se obtiene hidróxido de cinc. La destilación entre 100-150 • C de una suspensión acuosa del hidróxido de cinc produce la formación de partículas de óxido de cinc con morfología acicular. El tamaño de las partículas varía con las condiciones de obtención, siendo el tamaño estándar de 0.5 μm de diámetro y 5-8 μm de longitud. La eficacia del procedimiento es superior al 90 %.

Resumen: El presente trabajo debe encuadrarse en la especialidad de la Medicina Legal. Sin embargo, no deja de implicar un aporte en el aspecto cotidiano asistencial ya que la obtención de psicofármacos requiere, muchas veces, la involuntaria participación del médico en calidad de agente prescriptor de tales drogas. El (mal) uso de las benzodiazepinas por parte de algunos sujetos, concepto distinto al de abuso, es una situación frecuente en el ámbito carcelario. Esta genera especiales y gravísimos conflictos que pueden, y deben, ser minimizados por la simple restricción de la prescripción farmacológica si esta se ajusta a la evidencia científica (prescripción basada en la evidencia) y no a las demandas, muchas veces (in)justificadas de los mismos pacientes-reclusos. La búsqueda y obtención -por parte de ciertos sujetos portadores de una personalidad predisponente-de los efectos paradojales de las benzodiazepinas, parti-cularmente flunitrazepam y clonazepam, constituye un dato de la realidad que no puede ser desconocido ni minimizado por el médico asistencial ni por el experto en Medicina Legal, precisamente por las implicancias éticas, morales, sociales y, sobre todo, jurídicas que este supone, ni debe ser desoída la palabra profesional por los máximos responsables de la institución penitenciaria toda vez que a ellos compete el desarrollo e implementación de políticas tendientes a la cierta (re) socialización y (re) educación de la persona presa. Los destinatarios de este trabajo resultan entonces los médicos en general, con mayor énfasis en quienes trabajan en el medio penitenciario, pero también las autoridades del Servicio Penitenciario en todos sus escalafones y los integrantes del Poder Judicial.

Resumen: El presente trabajo debe encuadrarse en la especialidad de la Medicina Legal. Sin embargo, no deja de implicar un aporte en el aspecto cotidiano asistencial ya que la obtención de psicofármacos requiere, muchas veces, la involuntaria participación del médico en calidad de agente prescriptor de tales drogas. El (mal) uso de las benzodiazepinas por parte de algunos sujetos, concepto distinto al de abuso, es una situación frecuente en el ámbito carcelario. Esta genera especiales y gravísimos conflictos que pueden, y deben, ser minimizados por la simple restricción de la prescripción farmacológica si esta se ajusta a la evidencia científica (prescripción basada en la evidencia) y no a las demandas, muchas veces (in)justificadas de los mismos pacientes-reclusos. La búsqueda y obtención -por parte de ciertos sujetos portadores de una personalidad predisponente-de los efectos paradojales de las benzodiazepinas, parti-cularmente flunitrazepam y clonazepam, constituye un dato de la realidad que no puede ser desconocido ni minimizado por el médico asistencial ni por el experto en Medicina Legal, precisamente por las implicancias éticas, morales, sociales y, sobre todo, jurídicas que este supone, ni debe ser desoída la palabra profesional por los máximos responsables de la institución penitenciaria toda vez que a ellos compete el desarrollo e implementación de políticas tendientes a la cierta (re) socialización y (re) educación de la persona presa. Los destinatarios de este trabajo resultan entonces los médicos en general, con mayor énfasis en quienes trabajan en el medio penitenciario, pero también las autoridades del Servicio Penitenciario en todos sus escalafones y los integrantes del Poder Judicial.

Resumen: El presente trabajo debe encuadrarse en la especialidad de la Medicina Legal. Sin embargo, no deja de implicar un aporte en el aspecto cotidiano asistencial ya que la obtención de psicofármacos requiere, muchas veces, la involuntaria participación del médico en calidad de agente prescriptor de tales drogas. El (mal) uso de las benzodiazepinas por parte de algunos sujetos, concepto distinto al de abuso, es una situación frecuente en el ámbito carcelario. Esta genera especiales y gravísimos conflictos que pueden, y deben, ser minimizados por la simple restricción de la prescripción farmacológica si esta se ajusta a la evidencia científica (prescripción basada en la evidencia) y no a las demandas, muchas veces (in)justificadas de los mismos pacientes-reclusos. La búsqueda y obtención -por parte de ciertos sujetos portadores de una personalidad predisponente-de los efectos paradojales de las benzodiazepinas, parti-cularmente flunitrazepam y clonazepam, constituye un dato de la realidad que no puede ser desconocido ni minimizado por el médico asistencial ni por el experto en Medicina Legal, precisamente por las implicancias éticas, morales, sociales y, sobre todo, jurídicas que este supone, ni debe ser desoída la palabra profesional por los máximos responsables de la institución penitenciaria toda vez que a ellos compete el desarrollo e implementación de políticas tendientes a la cierta (re) socialización y (re) educación de la persona presa. Los destinatarios de este trabajo resultan entonces los médicos en general, con mayor énfasis en quienes trabajan en el medio penitenciario, pero también las autoridades del Servicio Penitenciario en todos sus escalafones y los integrantes del Poder Judicial.

To facilitate the learning of chemistry by means of problem-based and inquiry methods, at various educational levels, several proposals contextualized around iron medicines and supplements are presented. After a brief introduction to the role of iron in the human body, stoichiometry problems, an experimental practice for quantitative analysis of iron, and other practices for the preparation of various complexes are raised; all from different drugs containing this metal.

Introducción a la Química Orgánica Aprendiendo a Formular Alcanos, Alquenos, Alquinos, Nitrogenoides y Cetonas ¡Bienvenidos a un viaje fascinante al corazón de la materia! CÁPSULA DE APRENDIZAJE 3 QUÍMICA ORGÁNICA ¿Quiénes somos? Como estudiantes de segundo de bachillerato en Ciencias. Nos apasionan las ciencias naturales y entender cómo la química influye en la vida y la industria. Sentimos una especial curiosidad por la química aplicada en farmacología, alimentos y combustibles. Aunque la estructura y nomenclatura de compuestos orgánicos puede ser un reto, nos encanta aprender a través de actividades interactivas y visuales. Para conocernos mejor, puedes explorar este mapa conceptual. ¿Qué vamos a aprender? En esta cápsula, aprenderemos a identificar, nombrar y formular los compuestos orgánicos más fundamentales: Hidrocarburos saturados con enlaces simples. Hidrocarburos con al menos un doble enlace carbono-carbono. Hidrocarburos con al menos un triple enlace carbono-carbono. Compuestos que contienen nitrógeno, como aminas, amidas y nitroderivados. Compuestos orgánicos con un grupo carbonilo (C=O) dentro de la cadena. Explora estos compuestos en un simulador 3D de moléculas.

Janus gold nanostar–mesoporous silica nanoparticle (AuNSt–MSNP) nanodevices able to release an entrapped payload upon irradiation with near infrared (NIR) light were prepared and characterized. The AuNSt surface was functionalized with a thiolated photolabile molecule (5), whereas the mesoporous silica face was loaded with a model drug (doxorubicin) and capped with proton‐responsive benzimidazole‐β‐cyclodextrin supramolecular gatekeepers (N 1). Upon irradiation with NIR‐light, the photolabile compound 5 photodissociated, resulting in the formation of succinic acid, which induced the opening of the gatekeeper and cargo delivery. In the overall mechanism, the gold surface acts as a photochemical transducer capable of transforming the NIR‐light input into a chemical messenger (succinic acid) that opens the supramolecular nanovalve. The prepared hybrid nanoparticles were non‐cytotoxic to HeLa cells, until they were irradiated with a NIR laser, which led to intracellular doxorubicin rele...

Within many chemical and biological systems, both synthetic and natural, communication via chemical messengers is widely viewed as a key feature. Often known as molecular communication, such communication has been a concern in the fields of synthetic biologists, nanotechnologists, communications engineers, and philosophers of science. However, interactions between these fields are currently limited. Nevertheless, the fact that the same basic phenomenon is studied by all of these fields raises the question of whether there are unexploited interdisciplinary synergies. In this paper, we summarize the perspectives of each field on molecular communications, highlight potential synergies, discuss ongoing challenges to exploit these synergies, and present future perspectives for interdisciplinary efforts in this area.

El estudiante está obligado a utilizar un guarda polvos adecuado antes del ingreso al laboratorio e iniciar las practicas respectivas 2. Tiene que revisar su espacio y material de trabajo, asegurándose que esté totalmente limpio y en buenas condiciones antes de iniciar los experimentos. 3. Durante las sesiones prácticas estará prohibido provocar ruidos molestos, movimientos innecesarios, comer, fumar y conversar. 4. Los materiales y equipos de laboratorio deberán ser manipulado con el cuidado requerido. Cualquier daño es de responsabilidad exclusiva de quienes lo utilicen. Al concluir la sesión, el estudiante deberá dejar limpios los materiales, equipos y la superficie de las mesas de trabajo. 6. Los residuos sólidos deben ser tratados según las normas de bioseguridad antes de arrojarse en los receptores de basura expresamente dispuestos. 1. Antes de ingresar al laboratorio, lea siempre las instrucciones directrices del experimento que va a realizar. Espere las instrucciones del Docente antes de empezar a manipular los materiales y equipos de laboratorio. 3. Ejecute solamente las experiencias señaladas o aprobadas por el Docente. Están prohibidas las experiencias no autorizadas. 4. Ordene y rotule los materiales antes de empezar cada experimento. 5. Siga las instrucciones cuidadosamente y en forma precisa. En caso de duda consulte con el Docente y pregunte sobre sus inquietudes por más simple que parezcan. 6. Registre todos los resultados de sus experiencias en un cuaderno especial para ello. No se fie de su memoria, anoté siempre el nombre, día, hora, lugar y título de cada experimento.  Reconocer los riesgos más comunes en el laboratorio de Bioquímica.  Comprender y aplicar las normas y recomendaciones de bioseguridad en el laboratorio  Diferenciar los tipos de contención y su influencia en la salud humana e impacto ambiental. El Laboratorio es un ambiente físico que debe tener ciertas características en su diseño, aunque puede ser algo versátil teniendo en cuenta las actividades que en el se realizan, en este caso la enseñanza aprendizaje, el redescubrimiento e investigación. El Laboratorio debe tener una localización determinada con amplios ventanales y con ventilación adecuada, de tal forma no existan corrientes de aire, iluminación en concordancia con la amplitud evitando la incidencia directa de los rayos solares, para la noche instalaciones de luz blanca, la cual proporcione una iluminación optima, puede obtenerse oscuridad en el día mediante cortinas de color negro que se adaptarían. Posee diversos materiales y reactivos, en este caso los alumnos aprenderán como manipularlos y las precauciones que se deben tener; además debe contar con mesas impermeabilizadas, lo mismo las paredes hasta cierta altura lo que impedirá que absorban sustancias líquidas puedan caerles en forma accidental; pisos adecuados de fácil limpieza, instalaciones de agua, desagüe, gas, ambientes anexos; debe contar también con botiquín i/u extintores en caso de incendios, además de personal entrenado.  Siempre que realice experimentos en el laboratorio, utilice un mandil o guardapolvo.  El laboratorio es un lugar de trabajo serio, no fomente conversaciones, no realice ruidos molestos, movimientos excesivos.  No coma, ni fume, ni use cosméticos, no pasar la lengua por etiquetas ni permita que otros lo hagan.  Usar guantes para muestras como orina, sangre, mucosas, esputo.  No tocar con manos enguantadas los ojos, nariz y boca.  No juntar el guardapolvo con la ropa de calle.  Evitar salpicaduras y derrames.

Sensitive precise measurements were taken (high signal-to-noise ratios, 10-Pm image resolution, 99% scan-to-scan reproducibility). These features confirmed their potential as analytical tools, are a competitive alternative to fluorescence scanners, and incorporate additional advantages, such as user-friendly interface and connectivity for telemedicine needs. The analytical performances of the integrated platform (assay and reader) in the human samples were also excellent, with a low detection limit (100 genomic DNA copies), and reproducible (<15%) and cheap assays (< 10 €/test). The correct genotyping of a genetic biomarker (singlenucleotide polymorphism located in the GRIK4 gene) was achieved as the assigned genotypes agreed with those determined by using sequencing. The portability, favourable discriminating and read-out capabilities reveal that the implementation of mass-produced low-cost devices into minimal-specialised clinical laboratories is closer to becoming a reality.

The studied challenge is the specific detection of low-abundant genomic variants that differ by a single nucleotide from the wild type. The combination of blocked recombinase polymerase amplification (RPA) and selective capture by probes immobilised on magnetic-core particles integrated into a flow system is presented. The sensing principle was demonstrated as the effective concentration-detection of the specific generated products was achieved. The analytical performance of resulting assay was successfully compared to PCR-based methods or array formats, providing faster effective detection of the selective products. As proof of concept, the single-nucleotide substitutions of the KRAS gene at codon 12 were studied in chip with parallel microchambers and permanent magnets. The blocked RPA products (generated at 37 C) from tumour biopsies (extracted DNA 4 ng) provided a specific fluorescent bead-line that depends on the present mutation. The results agree with those reported by next-generation sequencing and provide new opportunities for in vitro diagnostic and personalised medicine.

Developing high-performance assays readout by integrated detectors is a current challenge to implement DNA tests into diagnostic laboratories, particularly for supporting pharmacogenetic tests. A method for allelic discrimination, associated with single nucleotide polymorphisms (SNPs), is presented. Genomic DNA is extracted from blood and buccal swab samples. The procedure comprises fast multiplex ligation-dependent probe amplification, PCR amplification using universal primers and subsequent barcode hybridization. In this last step, each product is recognized by the specific probes immobilized on the surface of an optical disc. Assay results can be collected with a disc reader. The optical sensing method in a DNA microarray format was optimized and evaluated for the simultaneous identification of 28 polymorphisms associated with psychiatry pharmacogenomics. The target biomarkers were located in the genes related to drug-metabolizing enzymes and drug transporters. The multiplexing capability and assay selectivity strongly depended on correct design (ligation probes, tails and barcodes). The discriminant analysis of reader outputs (spot intensities) led to patients being classified into different allelic populations. The obtained assignations correlated properly with the results provided by the reference technique (bead arrays), and the assay ended in an 8-fold shorter time using affordable equipment. The combination of high selective genotyping reaction as array-MLPA and the compact disc technology provide a reliable point-of-care approach. This genotyping tool is useful for selecting personalized drug therapies in decentralized clinical laboratories.

An integrated device composed of micro-reactors embedded onto compact discs is proposed for real-time targeted DNA determination. The method principle is based on in-disc loop-mediated isothermal amplification (iD-LAMP) and quantitative optical read-out by a disc drive. In the presence of a target, the turbidimetric or colorimetric properties of reaction solution change, and the transmitted intensity of the disc drive laser modifies according to reaction yield. Monitoring real-time curves allowed the quantitative determination of DNA template amounts. The best amplification/detection results were obtained with micro-reactors (2 mm diameter and 1.1 mm in depth) drilled on a digital video disc (DVD) and detection based on the colorimetric mode. As proofof-concept, the assay was applied to detect pathogenic bacteria Salmonella spp. and to identify bovine meat in food samples. Ninety-six samples were simultaneously analysed in 15 min, with high selectivity and sensitivity (5 CFU/mL and 10 µg/g for bacteria and meat, respectively). The in-disc results were comparable to those obtained by conventional LAMP or qPCR approaches. The developed device allows low sample and reagent consumption (3 µL of reaction), portability, ease-of-use, and rapid low-cost high-throughput analyses.

Diagnostic methods based on single nucleotide polymorphism (SNP) biomarkers are essential for the real adoption of personalized medicine. Allele specific amplification in a homogeneous format or combined to microarray hybridization are powerful approaches for SNP genotyping. However, primers must be properly selected to minimize cross-reactivity, dimer formation and nonspecific hybridization. This study presents a design workflow diagram for the selection of required oligonucleotides for multiplex assays. Based on thermodynamic restrictions, the oligonucleotide sets are chosen for a specific amplification of wild-and mutant-type templates. Design constraints include the structural stability of primer-template duplexes, template-probe duplexes and self-annealing complexes or hairpins for each targeted gene. The performance of the design algorithm was evaluated for the simultaneous genotyping of three SNPs related to immunosuppressive drugs administered after solid organ transplantation. The assayed polymorphisms were rs1045642 (ABCB1 gene), rs1801133 (MTHFR gene) and rs776746 (CYP3A5 gene). Candidates were confirmed by discriminating homozygote and heterozygote populations using a fluorescence solution method and two colorimetric microarray methods on polycarbonate chips. The analysis of patient samples provided excellent genotyping results compared to those obtained by a reference method. The study demonstrates that the development of the allele-specific methods as pharmacogenetic tools can be simplified.

The genotyping of a single-nucleotide polymorphism (SNP) is addressed through methods based on loop-mediated isothermal amplification (LAMP) combined with user-friendly optical read-outs to cover the current demand for point-of-care DNA biomarker detection. The modification of primer design and reaction composition improved the assay selectivity yielding allele-specific results and reducing false-positive frequency. Furthermore, the reduced cost, ease of use and effectiveness of colorimetric detection (solution and hybridization chip formats) were availed for the image capture by a smartphone, reching high sensitivity. In order to evaluate their discriminating capacities, LAMP-based methods were applied to human samples to genotype an SNP biomarker (rs1954787) located in the GRIK4 gene and related to the treatment response to anti-depressants drugs. Sensitive (limit of detection: 100 genomic DNA copies), reproducible (<15% error), fast (around 70 min) and low-cost assays were accomplished. Patient subgroups were correctly discriminated, agreeing with reference sequencing techniques. The achieved analytical performances using the developed amplification-detection principles confirmed the approach potential for point-of-care optical DNA testing.

An integrated sensor comprising isothermal DNA amplification and in situ detection is presented. The method principle is based on recombinase polymerase amplification (RPA) and detection in the microarray format by compact disc technology as a highthroughput sensing platform. Primers were immobilised on the polycarbonate surface of digital versatile discs (DVD) and, after hemi-nested amplification, multiplexing identification of each tethered product was achieved by optical scanning with a 650 nmlaser of the DVD drive. The efficiency of one-pot hybridisation/elongation/detection depended strongly on probe density and other factors such as the concentration of the unbound primers present in solution. The optimised conditions provided equivalent amplification factors (7.310 8  8.910 8 fold) to those obtained by conventional reactions performed in vials. The proposed method was applied to Salmonella detection (generic by hns and oriC genes, and specific for subspecies I by STM4507 gene). A triplex assay was satisfactorily compared to the non-integrated protocols. Food and vaccine samples were analysed in a shorter time with less handling. The results indicate that the multiplex DVD assay is a simple, competitive, isothermal, portable system that is particularly useful for microbiological routine analysis.

A blocked recombinase polymerase amplification (blocked-RPA) approach has been developed for the enrichment of mutated templates in heterogeneous specimens as tumor tissues. This isothermal amplification technique opens alternative solutions for meeting the technological demand of physician office laboratories. Herein, the detection of mutations in PIK3CA gene, such as p.E545K, and p.H1047L, is presented. The main element was an oligonucleotide (dideoxycytidine functionalized at 3'-end) which matched with wild-type sequence in the target locus. The amplification was performed operating at 37 ºC during 40 min. The results demonstrated that the competition between the upstream primer and the blocker reduced the percentage of amplified wild-type allele, making the detection of the present mutation easier. For mutation discrimination, a fast hybridization assay was performed in microarray format on plastic chip and colorimetric detection. This approach enabled the reliable discrimination of specific mutations against a background of up to 95% wild-type DNA. The applicability of the method, based on the combination of blocked-RPA and low-cost chip hybridization, was successfully proven for the genotyping of various cancer cell lines as well as tumor tissues. The assignations agreed with those provided by nextgeneration sequencing. Therefore, these investigations would support a personalized approach to patient care based on the molecular signature of human cancers.

A new advancement in massive DNA-based screening in limited-resource settings is demonstrated through the incorporation of easy-to-fabricate microfluidic chambers on digital versatile discs (DVDs) to perform isothermal recombinase polymerase amplification (RPA) in a microarray format. Standard un-modified DVD discs and commercial drives are used for the low-cost detection method. DNA primers were printed in a microarray format on the polycarbonate surfaces of DVDs with integrated control spots to guarantee the absence of false-negatives and false-positives. The solid-phase amplification assay, including the washing protocols and development reaction, was performed by the dispensation of solutions through the inlet and by controlling the flow-movement by DVD drive centrifugation. The final disc with reaction products was inserted into a DVD player and microarray images were captured and automatically processed. This simple approach was applied for the screening of genetically modified organisms (GMOs) in food samples. The limit of detection was 7 mg g À1 , which is well below the EU regulation limit for GMOs in food products. Therefore, the only required materials for food safety monitoring were standard store-bought DVDs, plastic chambers, tips, pipettes, an oven, and a standard DVD drive. The proposed strategy allows an integrated microarray system with low manipulation, reduced sample volume, and portability, which are beneficial for low-resource settings.

Pharmacological treatment of several diseases, such as attention deficit hyperactivity disorder (ADHD), presents marked variability in efficiency and its adverse effects. The genotyping of specific single nucleotide polymorphisms (SNPs) can support the prediction of responses to drugs and the genetic risk of presenting comorbidities associated with ADHD. This study presents two rapid and affordable microarray-based strategies to discriminate three clinically important SNPs in genes ADRA2A, SL6CA2, and OPRM1 (rs1800544, rs5569, and rs1799971, respectively). These approaches are allele-specific oligonucleotide hybridization (ASO), and a combination of allele-specific amplification (ASA) and solid-phase hybridization. Buccal swab and blood samples taken from ADHD patients and controls were analyzed by ASO, ASA and a gold-reference method. The results indicated that ASA is superior in genotyping capability and analytical performance.

This study presents a useful strategy for the bioconjugation of probes for developing high-performance versatile chips applied to fast-response, low-cost DNA biosensing. We herein demonstrate that the high-density immobilization of dendrimer-oligonucleotide hybrids promotes the reliable sensitive sensing of single-nucleotide variants despite their low concentration. Carboxyl-terminated poly(amidoamine) dendrimers directly coupled to amine-derivatized oligonucleotides were anchored to the activated surfaces of thermoplastics (polycarbonate and cycloolefin polymer). Surface characterization techniques and hybridization assays reported that the multiple functional sites of the oligofunctionalized dendrimer facilitated the efficient immobilization of probes and the sensitive capture of DNA targets (5 pM detection limit). Array performance was better than that of the surfaces functionalized with linear crosslinkers, such as vinyltriethoxysilane or 3-(triethoxysilyl)propyl isocyanate, as well films with unconjugated dendrimer molecules. Based on oligo-dendrimers hybrids, disposable DNA-based biosensing platforms were developed for point-ofcare diagnostics. A selective high-sensitive hybridization assay was performed that included amplification products of blocked PCR and recombinase polymerase amplification (RPA) as an isothermal reaction. The chip results indicated that the single-nucleotide mutant variant of the BRAF oncogene was correctly discriminated in colorectal tissues from cancer patients.

The studied challenge is the specific detection of low-abundant genomic variants that differ by a single nucleotide from the wild type. The combination of blocked recombinase polymerase amplification (RPA) and selective capture by probes immobilised on magnetic-core particles integrated into a flow system is presented. The sensing principle was demonstrated as the effective concentration-detection of the specific generated products was achieved. The analytical performance of resulting assay was successfully compared to PCR-based methods or array formats, providing faster effective detection of the selective products. As proof of concept, the single-nucleotide substitutions of the KRAS gene at codon 12 were studied in chip with parallel microchambers and permanent magnets. The blocked RPA products (generated at 37 C) from tumour biopsies (extracted DNA 4 ng) provided a specific fluorescent bead-line that depends on the present mutation. The results agree with those reported by next-generation sequencing and provide new opportunities for in vitro diagnostic and personalised medicine.

Sensitive precise measurements were taken (high signal-to-noise ratios, 10-Pm image resolution, 99% scan-to-scan reproducibility). These features confirmed their potential as analytical tools, are a competitive alternative to fluorescence scanners, and incorporate additional advantages, such as user-friendly interface and connectivity for telemedicine needs. The analytical performances of the integrated platform (assay and reader) in the human samples were also excellent, with a low detection limit (100 genomic DNA copies), and reproducible (<15%) and cheap assays (< 10 €/test). The correct genotyping of a genetic biomarker (singlenucleotide polymorphism located in the GRIK4 gene) was achieved as the assigned genotypes agreed with those determined by using sequencing. The portability, favourable discriminating and read-out capabilities reveal that the implementation of mass-produced low-cost devices into minimal-specialised clinical laboratories is closer to becoming a reality.

The genotyping of a single-nucleotide polymorphism (SNP) is addressed through methods based on loop-mediated isothermal amplification (LAMP) combined with user-friendly optical read-outs to cover the current demand for point-of-care DNA biomarker detection. The modification of primer design and reaction composition improved the assay selectivity yielding allele-specific results and reducing false-positive frequency. Furthermore, the reduced cost, ease of use and effectiveness of colorimetric detection (solution and hybridization chip formats) were availed for the image capture by a smartphone, reching high sensitivity. In order to evaluate their discriminating capacities, LAMP-based methods were applied to human samples to genotype an SNP biomarker (rs1954787) located in the GRIK4 gene and related to the treatment response to anti-depressants drugs. Sensitive (limit of detection: 100 genomic DNA copies), reproducible (<15% error), fast (around 70 min) and low-cost assays were accomplished. Patient subgroups were correctly discriminated, agreeing with reference sequencing techniques. The achieved analytical performances using the developed amplification-detection principles confirmed the approach potential for point-of-care optical DNA testing.

The costs of current genotyping methods limit their application to personalized therapy. The authors describe an alternative approach for the detection of single-point-polymorphisms (SNPs) using recombinase polymerase amplification (RPA) as an allele-specific technique. The use of short and chemically modified primers, locked nucleic acids (LNA), allowed the selective isothermal amplification of wild-type or mutant variants at 37 C in 40 min. An amplification chip containing 100 wells was manufactured with a 3D printer and using thermoplastic polylactic acid (PLA). The platform reduces costs, reagent consumption, sample volume and allows assay parallelization compared to other amplification formats. As proof of concept, the method was applied to the genotyping of four SNPs that are related to the treatment of tobacco addiction. The target polymorphisms were rs4680 (COMT gene), rs1799971 (OPRM1 gene), rs1800497 (ANKK1 gene), and rs16969968 (CHRNA5 gene). The capabilities of the method are demonstrated detecting the reaction products using a colorimetric technique in microarray format. The genotype populations can be well discriminated.

An integrated method for the parallelized detection of multiple DNA target sequences is presented by using microstructures in a digital versatile disc (DVD). Samples and reagents were managed by using both the capillary and centrifugal forces induced by disc rotation. Recombinase polymerase amplification (RPA), in a bridge solid phase format, took place in separate wells, which thereby modified their optical properties. Then the DVD drive reader recorded the modifications of the transmitted laser beam. The strategy allowed tens of genetic determinations to be made simultaneously within <2 h, with small sample volumes (3 µL), low manipulation and at low cost. The method was applied to the high-throughput screening of relevant safety threats (allergens, GMOs and pathogenic bacteria) in food samples. Satisfactory results were obtained in terms of sensitivity (48.7 fg of DNA) and reproducibility (below 18%). This detection scheme warranted cost-effective multiplex amplification and detection, and was perceived as a viable tool in the massive screening of nucleic acid targets.

An integrated device composed of micro-reactors embedded onto compact discs is proposed for real-time targeted DNA determination. The method principle is based on in-disc loop-mediated isothermal amplification (iD-LAMP) and quantitative optical read-out by a disc drive. In the presence of a target, the turbidimetric or colorimetric properties of reaction solution change, and the transmitted intensity of the disc drive laser modifies according to reaction yield. Monitoring real-time curves allowed the quantitative determination of DNA template amounts. The best amplification/detection results were obtained with micro-reactors (2 mm diameter and 1.1 mm in depth) drilled on a digital video disc (DVD) and detection based on the colorimetric mode. As proofof-concept, the assay was applied to detect pathogenic bacteria Salmonella spp. and to identify bovine meat in food samples. Ninety-six samples were simultaneously analysed in 15 min, with high selectivity and sensitivity (5 CFU/mL and 10 µg/g for bacteria and meat, respectively). The in-disc results were comparable to those obtained by conventional LAMP or qPCR approaches. The developed device allows low sample and reagent consumption (3 µL of reaction), portability, ease-of-use, and rapid low-cost high-throughput analyses.

An integrated sensor comprising isothermal DNA amplification and in situ detection is presented. The method principle is based on recombinase polymerase amplification (RPA) and detection in the microarray format by compact disc technology as a highthroughput sensing platform. Primers were immobilised on the polycarbonate surface of digital versatile discs (DVD) and, after hemi-nested amplification, multiplexing identification of each tethered product was achieved by optical scanning with a 650 nmlaser of the DVD drive. The efficiency of one-pot hybridisation/elongation/detection depended strongly on probe density and other factors such as the concentration of the unbound primers present in solution. The optimised conditions provided equivalent amplification factors (7.310 8  8.910 8 fold) to those obtained by conventional reactions performed in vials. The proposed method was applied to Salmonella detection (generic by hns and oriC genes, and specific for subspecies I by STM4507 gene). A triplex assay was satisfactorily compared to the non-integrated protocols. Food and vaccine samples were analysed in a shorter time with less handling. The results indicate that the multiplex DVD assay is a simple, competitive, isothermal, portable system that is particularly useful for microbiological routine analysis.

A valid solution for micro-analytical systems is the selection of a compatible amplification reaction with a simple, highly-integrated efficient design that allows the detection of multiple genomic targets. Two approaches under isothermal conditions are presented: recombinase polymerase amplification (RPA) and multiple displacement amplification (MDA). Both methods were applied to a duplex assay specific for Salmonella spp. and Cronobacter spp., with excellent amplification yields (0.2-8.6 10 8 fold). The proposed approaches were successfully compared to conventional PCR and tested for the milk sample analysis as a microarray format on compact disc (support and driver). Satisfactory results were obtained in terms of resistance to inhibition, selectivity, sensitivity (10 1 -10 2 CFU/mL) and reproducibility (below 12.5%). The studied methods are efficient and cost-effective, with a high potential to automate microorganisms detection by integrated analytical systems working at a constant low temperature.

Highly portable, cost effective and rapid-response devices are required for the subtyping of the most frequent food-borne bacteria, thereby the sample rejection strategies and hygienization techniques along of the food chain can be tailor-designed. Here, a novel biosensor is presented for the generic detection of Salmonella and Campylobacter and the discrimination between their most prevalent serovars (S. Enteritidis, S. Typhimurium) and species (C. jejuni, C. coli), respectively. The method is based on DNA microarray developed on a standard digital versatile disc (DVD) as support for a hybridization assay and a DVD driver as scanner. This approach was found to be highly sensitive (detection limit down to 0.2 pg of genomic DNA), reproducible (relative standard deviation 4-19 %), and high working capacity (20 samples per disc). The inclusivity and exclusivity assays indicated that designed oligonucleotides (primers and probes) were able to discriminate targeted pathogens from other Salmonella serovars, Campylobacter species or common food-borne pathogens potentially present in the indigenous microflora. One hundred isolates from meat samples, collected in a poultry factory, were analyzed by the DVD-microarraying and fluorescent real-time PCR. An excellent correlation was observed for both generic and specific detection (relative sensitivity 93-99 % and relative specificity 93-100 %). Therefore, the developed assay has been shown to be a reliable tool for use in routine food safety analysis, especially in settings with limited infrastructure due to the excellent efficiency-cost ratio of compact disc technology.

Xanthomonas arboricola pv. pruni is a quarantine pathogen and the causal agent of the bacterial spot disease of stone fruits and almond, a major threat to Prunus species. Rapid and specific detection methods are essential to improve disease management, and therefore a prototype of a lateral flow immunoassay (LFIA) was designed for the detection of X. arboricola pv. pruni in symptomatic field samples. It was developed by producing polyclonal antibodies which were then combined with carbon nanoparticles and assembled on nitrocellulose strips. The specificity of the LFIA was tested against 87 X. arboricola pv. pruni strains from different countries worldwide, 47 strains of other Xanthomonas species and 14 strains representing other bacterial genera. All X. arboricola pv. pruni strains were detected and cross-reactions were observed only with four strains of X. arboricola pv. corylina, a hazelnut pathogen that does not share habitat with X. arboricola pv. pruni. The sensitivity of the L...

Ahora debemos ver el misterio de la existencia con nuevos ojos, pues como hijos orgullosos de la ciencia y la razón, hemos quedado huérfanos de sabiduría. Deepak Chopra Con frecuencia los estudiantes de Química Orgánica se muestran abrumados por el número de compuestos, nombres, reactivos y mecanismos que confrontan, y se preguntan si podrán ser capaces de aprender todo ello en un solo semestre. La mayor parte de la química orgánica consiste en unos cuantos principios fundamentales y un gran número de extensiones y aplicaciones en esos principios. El estudiante requerirá, por lo tanto, de poca memorización si se interioriza de cada concepto principal y desarrolla flexibilidad para aplicarlo. Al ser la Química una ciencia experimental, considero de fundamental importancia para el alumno que pueda trasladar al laboratorio, los conceptos teóricos impartidos en el aula, donde podrá &quot;visualizar&quot; los mismos a través de las diversas prácticas presentadas por el docente. En las me...

VOCs are organic compounds that volatilize at room temperature and can cause serious problems for the environment and for the health of living beings. A quantitative and qualitative study of VOCs inside and outside the IES Plaza de la Cruz was carried out at two different times during the school year (week of January 19-25 and week of May 31-June 6), selecting a total of 19 sampling points. TENAX tubes were used to collect the samples by passive diffusion and the results were analyzed in the Integrated Environmental Quality Laboratory (LICA) of the Department of Chemistry at UNAV by gas chromatography. The hypothesis is that in winter there will be a higher quantity and concentration of VOCs than in summer, that the spaces facing San Fermín street will be more contaminated by these compounds, that certain areas such as laboratories, the Museum, the Ximénez teachers' room and the concierge will contain more VOCs and in higher concentrations than others. After analysing the samples, it is concluded that in winter more VOCs are recorded than in summer; that San Fermín street is not the one with the highest degree of VOC contamination but Tafalla street; that the laboratories have more VOC contamination but not the Museum, the Ximénez room or the concierge. The results indicate that all the concentrations obtained are well below the environmental limit values ​​of average daily exposure collected by the National Institute for Safety and Health at Work (2024) thanks to the role of natural ventilation. Finally, the sources of emissions of the VOCs obtained are analysed, reaching the conclusion that traffic and heating are the main sources outside the centre, especially in winter. Inside, the main sources are heating, cleaning products and plants.