Dispositivos microfluidos operados por fuerzas capilares son fáciles de operar plataformas para realizar herramientas Lab-On-a-Chip (LOC). Si estas “simplistas” aplicaciones LOC tengan éxito, la operación unitaria del control de flujo hay que desarrollarse. Esto es particularmente verdad para herramientas “ASSURED” (término introducido por A. Guiseppi-Elie: Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Deliverable) y aplicaciones bioanalíticas en las cuales la respuesta depende de la disolución de los reactivos previamente depositados, la cinética de afinidad biológica y enzimática, y el transporte en materia de productos a un transductor en los microcanales. En esta tesis el diseño, fabricación e implementación de tres alternativas electroquímicas para el control del flujo capilar se han desarrollado basadas en electrowetting usando i) superficies superhidrófobas basándose a polímeros que responden inteligentemente a los estímulos eléctricos, ii) superficies nanoporosas superhidrófobas de electrodos de carbono, y iii) electrodos con superficies superhidrófobas acoplados a otros electrodos que facilitan la generación de gradientes que pueden propulsar el líquido. La tesis estudia el mecanismo de la respuesta en cada caso en estos sistemas y demuestra opciones para la reducción a la práctica de herramientas que pueden “democratizar” la “teranostica” (theranostics). / Capillary force-operated microfluidic devices are easy to use, low cost realization platforms for Lab-on-a-Chip (LOC) configurations. If such “simplistic” LOC applications are to have success, flow control is an important unit operation to develop. This is particularly true for ASSURED (a term introduced by A. Guiseppi-Elie: Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Deliverable) devices for bioanalytical applications where an analytical response depends on the dissolution of previously deposited reagents, the kinetics of biological affinity and enzymatic reactions, and mass transport of products to a transducer in the microchannels. In this thesis the design, fabrication and implementation of three different electrochemically actuated capillary flow control schemes have been developed through low voltage electrowetting/ electrochemical actuation of the flow using i) electrical stimuli responsive superhydrophobic surfaces based on intelligent polymers ii) superhydrophobic nanoporous carbonaceous surfaces, and iii) superhydrophobic electrodes coupled to other electrodes that facilitate the generation of gradients to propel the liquid. The thesis unravels the mechanism of response of such systems and demonstrates ways for reduction to practice of such devices for the “democratization” of theranostics.

Due to the nuclear testing, reentry and disintegration of nuclear powered satellites, nuclear reactor accidents, uranium nuclear fuel cycle and nuclear weapons production, actinides have been introduced into the environment. Proposed disposal of high-level radioactive waste in mined repositories in geologic formation as well as the storage and disposal of uranium and plutonium from weapons dismantlement are further possible sources for actinide releases to the environment. The mobilization of radionuclides in the environment has been studied for many years with the prime objective of tracing the routes by which they accumulate in the food chain and become available for human consumption. Therefore, it is necessary to have available accurate, reliable and precise analytical methods to determine actinides and fission products in environmental samples as well as their isotopic ratio. These procedures should also be as fast as possible in order to give results in radiological emergency cases to take decision for radiation protection of the environment and human beings.In this Ph.D. thesis, different kinds of phases for liquid chromatography have been tested to achieve the separation of the interfering elements and isotopes before the mass spectrometry and -spectrometry measurements. UTEVA and TEVA extraction resin (Eichrom Industries, USA) have been packed in chromatographic column as stationary phases and used for the separation of tri, tetra and hexavalent actinides and for the separation of trivalent lanthanides (La-Eu) and actinides, respectively. IonPac CS5A and CS10 (Dionex, Sunnyvale, USA) ion chromatography column were used for the simultaneous separation of actinide and lanthanides elements and for the actinides separation. The columns were coupled on-line to an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) to solve isobaric interferences between actinide and lanthanide elements and off-line to a -spectrometer to solve the energy interferences between the analytes. Moreover, an investigation on the use of the UTEVA resin and IonPac Trace Cation Concentrator II column (TCC-II from Dionex, Sunnyvale, USA) as preconcentrator columns for actinide and lanthanide elements has been carried-out.The analytical measurements have been made by mass spectrometric as well as by radiometric techniques. ICP-MS has been used for the characterization of spent nuclear fuels in terms of actinides and lanthanides content and burn-up calculation as well as for the determination of the long-lived actinides and lanthanides in environmental samples. - and -spectrometry have been used for 241Am determination in sediments and soils samples. -spectrometry and Liquid Scintillation Counting (LSC) have been used to analyze the eluted fractions from on-batch experiments. The results obtained with the analytical procedures developed, for spent nuclear fuel solutions as well as for environmental samples, were always compared to those obtained by other independent techniques and good agreements have been always achieved.

Tesi per compendi de publicacions. La consulta íntegra de la tesi, inclosos els articles no comunicats públicament per drets d'autor, es pot realitzar prèvia petició a l'Arxiu de la UPC / Analytical disciplines are an important field for the progress of healthcare and medicine. In fact the technologies related to analytical disciplines may reveal important information for early diagnosis, treatment of diseases, food safety and environmental monitoring. In this regard, novel advances in analytical disciplines are highly desired. As a promising tool, biosensors are useful systems that enable the detection of agents with diagnostic interest. Since nanotechnology enables the manipulation and control at the nanoscale, biosensors based on nanotechnology offer powerful capabilities to diagnostic technology. In this dissertation, the advantages of the integration of nanomaterials into microarray technology are widely studied, generally in terms of sensitivity. Particularly, the performance of cadmium-selenide/zinc-sulfide (CdSe@ZnS) quantum dots (QDs) and the fluorescent dye Alexa 647 as reporter in an assay designed to detect apolipoprotein E (ApoE) has been compared. The assay is a sandwich immunocomplex microarray that functions via excitation by visible light. ApoE was chosen for its potential as a biomarker for Alzheimer's disease. The two versions of the microarray (QD or Alexa 647) were assessed under the same experimental conditions. The QDs proved to be highly e¿ective reporters in the microarrays, although their performance strongly varied in function of the excitation wavelength. At 633 nm, the QD microarray, at an excitation wavelength of 532 nm, provided a limit of detection (LOD) of ~62 pg mL-1, ¿ve times more sensitive than that of the Alexa microarray (~307 pg mL-1). Finally, serial dilutions from a human serum sample were assayed with high sensitivity and acceptable precision and accuracy (Anal. Chem. 2012, 84:6821). Since graphene oxide (GO) is a recently discovered nanomaterial and microarray technology relies on optical signals, the photonic properties of GO are discussed and the state-of-the-art of GO in optical biosensing has been widely documented (Adv. Mater. 2012, 24:3298). Furthermore, GO has been studied as a highly efficient quencher of QDs, reporting a quenching efficiency of nearly 100%. Finally, such interaction between GO and QDs has been proposed as a highly sensitive transduction system for microarray-based biodetection (Carbon 2012, 50:2987). This research aims at demonstrating how the endeavour of the fusion between nanomaterials and microarray technology exhibits enormous possibilities towards biomarker screening, food safety and environmental monitoring. / Las tecnologías relacionadas con el diagnóstico son un campo importante para el progreso de la medicina y el cuidado de las salud. Por ejemplo, estas tecnologías pueden aportar valiosa información para el tratamiento y diagnóstico temprano de enfermedades, seguridad en alimentos y monitoreo del medio ambiente. En este contexto, los sistemas de biosensado son una herramienta muy prometedora que permite la detección de agentes con interés diagnostico. Dado que la nanotecnología facilita la manipulación y control a la nanoescala, los sistemas de biodetección basados en nanotecnología poseen poderosas capacidades que pueden ser explotadas en las tecnologías relacionadas con el diagnóstico. En esta tesisis se han estudiado las ventajas que aporta la integración de nanomateriales a la tecnología de microarrays, generalmente en términos de sensibilidad. Particularmente, se ha estudiado el desempeño de la integración de nanocristales semiconductores (NS) para la detección de un biomarcador relacionado con Alzheimer en formato microarray. En dicho microarray se ha observado un importante rendimiento, mostrando un excelente limite de detección de 62 pg mL-1, el cual supera a otros metodos convencionales de detección como el ELISA (470 pg mL-1). También se ha analizado un banco de diluciones de una muestra de suero humano con precisión y exactitud aceptables (Anal. Chem. 2012, 84:6821). Por otra parte, ya que el óxido de grafeno (OG) es un material muy novedoso y la tecnología de microarrays depende de señales ópticas, se ha documentado ampliamente el estado del arte sobre el uso de (OG) en en el campo del biosensado óptico (Adv. Mater. 2012, 24:3298). Adicionalmente, se ha estudiado al OG como un desactivador de fluorescencia de NS altamente eficiente, presentando una eficiencia en la desactivación de NS de casi el 100%. Finalmente se ha aplicado dicha interacción entre NS y OG para diseñar un sistema de transducción altamente sensible (Carbon 2012, 50:2987 ). Esta investigación tiene por objetivo demostrar las ventajas y el potencial que posee la fusión entre los nanomateriales y la tecnología de microarrays como un sistema aplicado al campo del diagnóstico