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Laboratoire d’analyse et d’architecture des systèmes

Publications de l'équipe MILE

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59documents trouvés

18315
19/10/2018

Mechano-chemostats to study the effects of compressive stress on yeast

L.J.HOLT, O.HALLATSCHEK, M.DELARUE

New York, Berkeley, MILE

Ouvrage (contribution) : Microfluidics in Cell Biology Part B: Microfluidics in Single Cells, N°ISBN 978-0-12-814282-0, Vol.147231, Octobre 2018, 215p. , N° 18315

Lien : https://hal.archives-ouvertes.fr/hal-01886064

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Abstract

Cells need to act upon the elastic extracellular matrix and against steric constraints when proliferating in a confined environment, leading to the build-up, at the population level, of a compressive, growth-induced, mechanical stress. Compressive mechanical stresses are ubiquitous to any cell population growing in a spatially-constrained environment, such as microbes or most solid tumors. They remain understudied, in particular in microbial populations, due to the lack of tools available to researchers. Here, we present various mechano-chemostats: microfluidic devices developed to study microbes under pressure. A mechano-chemostat permits researchers to control the intensity of growth-induced pressure through the control of cell confinement, while keeping cells in a defined chemical environment. These versatile devices enable the interrogation of physiological parameters influenced by mechanical compression at the single cell level and set a standard for the study of growth-induced compressive stress.

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18279
28/09/2018

Correlation between DNA Self-Assembly Kinetics, Microstructure, and Thermal Properties of Tunable Highly Energetic Al–CuO Nanocomposites for Micropyrotechnic Applications

T.CALAIS, A.BANCAUD, A.ESTEVE, C.ROSSI

NEO, MILE

Revue Scientifique : ACS Applied Nano Materials, Vol.1, N°9, pp.4716-4725, Septembre 2018 , N° 18279

Lien : https://hal.archives-ouvertes.fr/hal-01874446

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The association of a metallic fuel (usually aluminum) with an oxidizer (metal oxide or organic compound) creates an exothermic material that can be ignited with an external stimulus such as local heating or spark discharge. These materials with high energetic performances, called nanothermites, have been used to release temperature or pressure waves for civil or military applications (initiators, impact igniters, etc.). However, the energetic performances of these nanothermites are highly dependent on the nanoscale intimacy of the two components. The use of nanoparticles results in an increase of the energy release, but control of their assembly remains particularly challenging. In this work, we demonstrate that the use of DNA to self-organize Al or CuO nanoparticles greatly enhances the energy release of nanothermites by up to 240% compared to classically sonicated nanothermites in hexane, with the heat of reaction prior to Al melting reaching a value of 2.57 kJ·g–1. In particular, we report that the energetic performances can be tuned by controlling the ionic strength during the self-assembly process. These results are supported by ultrafine characterization of the nanocomposite microstructure based on high-resolution transmission electronic microscopy and energy-dispersive X-ray spectroscopy. Besides, we report the surprisingly good energetic performances of randomly mixed nanoparticles dispersed in water, nonetheless 40% lower than DNA-self-assembled nanocomposites. Altogether, our study not only proposes an easy and immediate process for nanocomposites synthesis but also opens the door for opportunities toward large-scale crystalline Al–CuO superlattices with high energetic performances.

144600
18144
01/08/2018

Hybrid vesicles from lipids and block copolymers: phase behavior from the micro-to the nano-scale

C.MAGNANI, C.MONTIS, G.MANGIAPIA, A.F.MINGOTAUD, C.MINGOTAUD, C.ROUX, P.JOSEPH, D.BERTI, B.LONETTI

IMRCP, UNIFI, Forschungszentrum, MILE

Revue Scientifique : Colloids and Surfaces B: Biointerfaces, Vol.168, pp.18-28, Août 2018 , N° 18144

Lien : https://hal.laas.fr/hal-01810239

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In recent years, there has been a growing interest in the formation of copolymers-lipids hybrid self-assemblies, which allow combining and improving the main features of pure lipids-based and copolymer-based systems known for their potential applications in the biomedical field. In this contribution we investigate the self-assembly behavior of dipalmitoylphosphatidylcholine (DPPC) mixed with poly(butadiene-b-ethyleneoxide) (PBD-PEO), both at the micro- and at the nano-length scale. Epifluorescence microscopy and Laser Scanning Confocal microscopy are employed to characterize the morphology of micron-sized hybrid vesicles. The presence of fluid-like inhomogeneities in their membrane has been evidenced in all the investigated range of compositions. Furthermore, a microfluidic set-up characterizes the mechanical properties of the prepared assemblies by measuring their deformation upon flow: hybrids with low lipid content behave like pure polymer vesicles, whereas objects mainly composed of lipids show more variability from one vesicle to the other. Finally, the structure of the nanosized assemblies is characterized through a combination of Dynamic Light Scattering, Small Angle Neutron Scattering and Transmission Electron Microscopy. A vesicles-to-wormlike transition has been evidenced due to the intimate mixing of DPPC and PBD-PEO at the nanoscale. Combining experimental results at the micron and at the nanoscale improves the fundamental understanding on the phase behavior of copolymer-lipid hybrid assemblies, which is a necessary prerequisite to tailor efficient copolymer-lipid hybrid devices.

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17438
01/08/2018

Pore cross-talk in colloidal filtration

O.LIOT, S.AKASH, P.BACCHIN, P.DURU, J.MORRIS, P.JOSEPH

MILE, LGC, IMFT, Levich Institute

Revue Scientifique : Scientific Reports, Vol.8, 12460p., Août 2018 , N° 17438

Lien : https://hal.archives-ouvertes.fr/hal-01865363

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Blockage of pores by particles is found in numerous industrial and natural processes, including filtration and oil extraction. We present experimental results of filtration through a linear array of ten channels with one dimension which is sub-micron. These silicon-glass nanoslits serve as model pores, through which a dilute dispersion of Brownian polystyrene spheres flows. The clog growth rate at fixed differential pressure is shown to systematically increase with the number of saturated (entirely clogged) pores, indicating that there is an interaction or " cross-talk " between the pores. This observation is interpreted using a model proposed here, based on the concept that the residual permeability allows a clog to act as a filter. A clogged pore is thus the source of a local increase of particle concentration adjacent to the pore, which then diffuses towards other pores. This phenomenon, evidenced and modelled here in one dimension, should be at play in two-dimensional membranes.

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18179
23/05/2018

Simple Synthetic Molecular Hydrogels from Self- Assembling Alkylgalactonamides as Scaffold for 3D Neuronal Cell Growth

A.CHALARD, L.VAYSSE, P.JOSEPH, L.MALAQUIN, S.ASSIE-SOULEILLE, B.LONETTI, J.C.SOL, I.LOUBINOUX, J.FITREMANN

MILE, INSERM, ELIA, I2C, IMRCP

Revue Scientifique : ACS applied materials & interfaces, Vol.10, N°20, pp.17004-17017, Mai 2018 , N° 18179

Lien : https://hal.laas.fr/hal-01810656

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In this work, we demonstrated that the hydrogel obtained from a very simple and single synthetic molecule, N-heptyl-galactonamide was a suitable scaffold for the growth of neuronal cells in 3D. We evidenced by confocal microscopy the presence of the cells into the gel up to a depth of around 200 µm, demonstrating that the latter was permissive to cell growth and enabled a true 3D colonization and organization. It also supported successfully the differentiation of adult human neuronal stem cells (hNSCs) into both glial and neuronal cells and the development of a really dense neurofilament network. So the gel appears to be a good candidate for neural tissue regeneration. In contrast with other molecular gels described for cell culture, the molecule can be obtained at the gram scale by a one-step reaction. The resulting gel is very soft, a quality in accordance with the aim of growing neuronal cells, that requires low modulus substrates similar to the brain. But because of its fragility, specific procedures had to be implemented for its preparation and for cell labeling and confocal microscopy observations. Notably, the implementation of a controlled slow cooling of the gel solution was needed to get a very soft but nevertheless cohesive gel. In these conditions, very wide straight and long micrometric fibers were formed, held together by a second network of flexible narrower nanometric fibers. The two kinds of fibers guided the neurite and glial cell growth in a different way. We also underlined the importance of a tiny difference in the molecular structure on the gel performances: parent molecules, differing by a one-carbon increment in the alkyl chain length, N-hexyl-galactonamide and N-octyl-galactonamide, were not as good as N-heptyl-galactonamide. Their differences were analysed in terms of gel fibers morphology, mechanical properties, solubility, chain parity and cell growth.

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18148
27/04/2018

Transport of nano-objects in narrow channels: influence of Brownian diffusion, confinement and particle nature

O.LIOT, M.SOCOL, L.GARCIA, J.THIERY, A.FIGAROL, A.F.MINGOTAUD, P.JOSEPH

MILE, IPBS, IMRCP

Revue Scientifique : Journal of Physics: Condensed Matter, Vol.30, N°23, 23400p., Avril 2018 , N° 18148

Lien : https://hal.laas.fr/hal-01810125

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This paper presents experimental results about transport of dilute suspensions of nano-objects in silicon-glass micrometric and sub-icrometric channels. Two kinds of objects are used: solid, rigid latex beads and spherical capsule-shaped, soft polymersomes. They are tracked using fluorescence microscopy. Three parameters are studied: confinement (ratio between particle diameter and channel depth), Brownian diffusion and particle nature. The aim of this work is to understand how these different parameters affect the transport of suspensions in narrow channels and to understand the different mechanisms at play. Concerning the solid beads we observe the appearance of two regimes, one where the experimental mean velocity is close to the expected one and another where this velocity is lower. This is directly related to a competition between confinement, Brownian diffusion and advection. These two regimes are shown to be linked to the homogeneity of particles distribution in the channel depth, which we experimentally deduce from velocity distributions. This inhomogeneity appears during the entrance process into the sub-micrometric channels, as for hydrodynamic separation or deterministic lateral displacement. Concerning the nature of the particles we observed a shift of transition towards the second regime likely due to the relationships between shear stress and polymersomes mechanical properties which could reduce the inhomogeneity imposed by the geometry of our device.

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18216
22/03/2018

Modeling of microfluidically tuned capacitor for RF applications

N.HABBACHI, H.BOUSSETTA, M.A.KALLALA, A.BOUKABACHE, P.PONS, K.BESBES

Monastir, MILE, MINC

Manifestation avec acte : International Multi-Conference on Systems, Signals and Devices ( SSD ) 2018 du 19 mars au 22 mars 2018, Hammamet (Tunisie), Mars 2018, 5p. , N° 18216

Lien : https://hal.laas.fr/hal-01838593

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This paper presents the modeling of microfluidically tuned capacitor for RF applications. The designed structure is based on performances variations following DI water displacement between capacitor's electrodes. We have modeled the electric field and the current distribution using FEM tool for different DI water position in microchannels. The obtained results at 4.5 GHz show an important variation of electric field and current distribution that impacts the capacitor performances: the capacitance value is comprised between Cmin = 0.11 pF and Cmax = 5.76 pF, the factor value decreases from Qmax = 84.27 to Qmin = 3.99, and the resonant frequency ranges from 5.67 GHz to 19.8 GHz. Indeed, the capacitance variation reaches Tr = 5136% and the broadband ability is higher than 240%.

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18217
22/03/2018

Design and simulation of 10 GHz VCO based on RF MEMS solenoid inductor

N.HABBACHI, H.BOUSSETTA, M.A.KALLALA, A.BOUKABACHE, P.PONS, K.BESBES

Monastir, MILE, MINC

Manifestation avec acte : International Multi-Conference on Systems, Signals and Devices ( SSD ) 2018 du 19 mars au 22 mars 2018, Hammamet (Tunisie), Mars 2018, 5p. , N° 18217

Lien : https://hal.laas.fr/hal-01838589

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This paper reports the design and simulation of 10 GHz VCO based on RF MEMS solenoid inductor. We have investigated four RF MEMS solenoid inductors using FEM software. Indeed, we have studied the effect of different dielectric substrate and metallic coil on inductors responses. Higher performances are obtained using copper coil and SU8 dielectric substrate: SRF= 20.8 GHz, Qmax= 60.9, and L = 2.6 nH at 10 GHz. Therefore, we have designed and investigated a cross-coupled CMOS VCO based on the best RF MEMS solenoid inductor. The obtained results show a wide tuning range TR = 46% comprised between 10 GHz and 14.6 GHz, and a good linearity of frequency variation in response of control voltage. Moreover, output signals present a high voltage upper than 1.2 V and a low phase-noise PN =-102.37 dBc/Hz at 1 MHz. In addition, the spectral analyze show that output peak power reaches 14.56 dBm at a center frequency of 10 GHz and the second harmonic is less than-58.9 dBm. These results prove high spectral signal ability of the proposed RF MEMS CMOS VCO at 10 GHz.

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18096
01/03/2018

Spatial Analysis of Nanofluidic-Embedded Biosensors for Wash-Free Single-Nucleotide Difference Discrimination

J.CACHEUX, M.BRUT, A.BANCAUD, P.CORDELIER, T.LEICHLE

MEMS, M3, MILE, CRCT-INSERM

Revue Scientifique : ACS Sensors, Vol.3, N°3, pp.606-611, Mars 2018 , N° 18096

Lien : https://hal.laas.fr/hal-01762631

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In this work, we demonstrate that the analysis of spatially resolved nanofluidic-embedded biosensors permits the fast and direct discrimination of single-nucleotide difference (SND) within oligonucleotide sequences in a single step interaction. We design a sensor with a linear dimension much larger than the channel depth in order to ensure that the reaction over the whole sensor is limited by the convection rate. Thus, the targets are fully collected, inducing a nonuniform spatial hybridization profile. We also use the nanoscale height of the channel, which enables us to minimize the amount of labeled molecules flowing over the sensor and hence to reduce the fluorescence background, to carry out real-time hybridization detection by fluorescence microscopy. Taken together, these design rules allow us to show that the spatial hybridization profile depends on the duplex affinity, and we speculate that the on and off-rate constants can be inferred during target injection, which is not possible in local analysis where the dissociation step through rinsing must be conducted. We finally manage to discriminate a GT mismatch on a microRNA sequence by optimizing the interaction temperature and the probe design after a few minutes of interaction in a single step protocol. This work may be applied to any biosensing transduction scheme with spatial resolution, e.g., surface plasmon resonance imaging, integrated into nanofluidic channels for applications where high oligonucleotide sequence selectivity and short analysis times are required.

143275
18069
25/02/2018

Evaporation with the formation of chains of liquid bridges

C.CHEN, P.JOSEPH, S.GEOFFROY, M.PRAT, P.DURU

IMFT, MILE, LMDC

Revue Scientifique : Journal of Fluid Mechanics, Vol.837, pp.703-728, Février 2018 , N° 18069

Lien : https://hal.laas.fr/hal-01701199

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The objective of the present work is to study the drying of a quasi-2D model porous medium, thereafter called micromodel, initially filled with a pure liquid. The micromodel consists of cylinders measuring 50 µm in both height and diameter, radially arranged as a set of neighbouring spirals and sandwiched between two horizontal, flat plates. As drying proceeds, air invades the pore space and elongated liquid films trapped by capillary forces form along the spirals. These films consist of " chains " of liquid bridges connecting neighbouring cylinders. They provide an hydraulic connectivity between the central, bulk liquid cluster and the external rim of the cylinders pattern, where evaporation is taking place during a first constant evaporation-rate drying stage. The first goal of the present paper is to describe experimentally the phase distribution during drying, notably the liquid films evolution, which controls the evaporation kinetics (e.g. the depinning of the films from the external rim signs the end of the constant evaporation rate period). Then, a visco-capillary model for the drying process is presented. It is based on numerical simulations of a liquid film capillary shape and of the viscous flow within a film. The model shows a reasonably good agreement with the experimental data. Thus, the present study is a step towards direct modelling of the films effect on the drying of more complex porous media (e.g. packing of beads) and should be of interest for multiphase flow applications in porous media, involving transport within liquid films.

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