Análisis Numérico del Efecto de la Termoforesis para la Separación de Diferentes Poblaciones de Exosomas

Los sistemas microfluídicos han demostrado ser una alternativa prometedora ante procesos convencionales de separación y caracterización. Este trabajo muestra el estudio numérico del fenómeno de la termoforesis en un microdispositivo para la separación de diferentes poblaciones de exosomas (vesículas entre 40-250nm liberadas por la mayoría de las células) en base a su tamaño. Empleando el software ANSYS Fluent v.16.0 se han analizado diferentes modelos geométricos del microdispositivo, gradientes de temperatura entre la pared superior e inferior y flujos de entrada, con el fin de determinar la trayectoria de los exosomas a través del dispositivo microfluídico y extraer las diferentes poblaciones. En base a los resultados obtenidos se muestra el dispositivo propuesto para la fabricación de un dispositivo eficiente

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Microfluidic separation processes using the thermodiffusion effect

The numerical and experimental results presented in this work show that a relatively small temperature gradient (5K), has great potential to generate a separation in interesting mixtures for biological purpose. In fact, it improves molecular diffusion separation process of a protective cryo (10% of dimethyl sulfoxide (DMSO) in phosphate buffered saline (PBS)) for cryopreserved cells, by 10%. This separation process was analyzed both numerically and experimentally, for which it was necessary to determine experimentally the thermophysical and transport properties of the mixture of 10% of DMSO in PBS. Experimental tests were done in a microdevice with a working section of 500μ m × 25 mm and a length of 75 mm, which was designed, constructed and first of all validated with the mixture of reference H2O-Isopropanol at a mass fraction of 50%. Experimental test with the protective cryo were done with in flow rates between 1000μL/min and 4000μL/min. The results confirm that the effect of thermodiffusion must be considered in handling processes of biological fluid mixtures because the existence of a thermal gradient could improve the efficiency of the separation process in microdevices

Fluorescent bicolour sensor for low-background neutrinoless double β decay experiments

Observation of the neutrinoless double β decay is the only practical way to establish that neutrinos are their own antiparticles. Because of the small masses of neutrinos, the lifetime of neutrinoless double β decay is expected to be at least ten orders of magnitude greater than the typical lifetimes of natural radioactive chains, which can mimic the experimental signature of neutrinoless double β decay. The most robust identification of neutrinoless double β decay requires the definition of a signature signal—such as the observation of the daughter atom in the decay—that cannot be generated by radioactive backgrounds, as well as excellent energy resolution. In particular, the neutrinoless double β decay of Xe could be established by detecting the daughter atom, Ba, in its doubly ionized state. Here we demonstrate an important step towards a ‘barium-tagging’ experiment, which identifies double β decay through the detection of a single Ba ion. We propose a fluorescent bicolour indicator as the core of a sensor that can detect single Ba ions in a high-pressure xenon gas detector. In a sensor made of a monolayer of such indicators, the Ba dication would be captured by one of the molecules and generate a Ba-coordinated species with distinct photophysical properties. The presence of such a single Ba-coordinated indicator would be revealed by its response to repeated interrogation with a laser system, enabling the development of a sensor able to detect single Ba ions in high-pressure xenon gas detectors for barium-tagging experiments.We also acknowledge support from the following agencies and institutions: the European Research Council (ERC) under Advanced Grant 339787-NEXT; the Ministry of Science and Innovation of Spain and FEDER under grants FIS2014-53371-C04, FIS2016-76163-R, MAT2016-78293-C6-5-R, MINECO/FEDER CT2016-80955-P, CTQ2016-80375-P and CTQ2014-51912-REDC; Interred PCTEFA V-A Spain/France/Andorra Program (EFA 194/16/TNSI); the Basque Government (GV/EJ) under grants IT-1346-19 and IT-1180-19; andAgencia de Ciencia y Tecnología de la Región de Murcia (19897/GERM/15). The authors also thank the SGI/IZO-SGIker UPV/EHU, Fundación Séneca and DIPC for computational and analytical resources