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17089
22/05/2017

Effect of growth-induced X-ray exposure on the transport, magnetotransport and luminescence properties of OLEDs

R.MONFLIER, F.SEKLI, L.SALVAGNAC, I.SEGUY, E.BEDEL-PEREIRA, J.F.BOBO

MPN, MICA, TEAM, CEMES/CNRS

Manifestation avec acte : E-MRS Spring Meeting 2017 du 22 mai au 26 mai 2017, Strasbourg (France), Mai 2017, 1p. , N° 17089

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139526
16320
01/04/2017

Multi-MHz micro-electro-mechanical sensors for atomic force microscopy

B.LEGRAND, J.P.SALVETAT, B.WALTER, M.FAUCHER, D.THERON, J.P.AIME

MEMS, CRPP, Pessac, IEMN Villeneuve, CBMN

Revue Scientifique : Ultramicroscopy, Vol.175, pp.46-57, Avril 2017 , N° 16320

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Abstract

Silicon ring-shaped micro-electro-mechanical resonators have been fabricated and used as probes for dynamic atomic force microscopy (AFM) experiments. They offer resotnance frequency above 10 MHz, which is notably greater than that of usual cantilevers and quartz-based AFM probes. On-chip electrical actuation and readout of the tip oscillation are obtained by means of built-in capacitive transducers. Displacement and force resolutions have been determined from noise analysis at 1.5 fm/√Hz and 0.4 pN/√Hz, respectively. Despite the high effective stiffness of the probes, the tip-surface interaction force is kept below 1 nN by using vibration amplitude significantly below 100 pm and setpoint close to the free vibration conditions. Imaging capabilities in amplitude- and frequency-modulation AFM modes have been demonstrated on block copolymer surfaces. Z-spectroscopy experiments revealed that the tip is vibrating in permanent contact with the viscoelastic material, with a pinned contact line. Results are compared to those obtained with commercial AFM cantilevers driven at large amplitudes (>10 nm).

139001
17062
09/03/2017

Spectroscopie diélectrique HyperFréquence des cellules biologiques soumisee à l'électroporation

A.TAMRA

MH2F

Doctorat : Université de Toulouse III - Paul Sabatier, 9 Mars 2017, 164p., Président: S.YOSHIZAWA, Rapporteurs: O.FRANCAIS, P.RENAUD, Examinateurs: K.GRENIER, Directeurs de thèse: D.DUBUC, M.P.ROLS , N° 17062

Lien : https://hal.laas.fr/tel-01499406

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Abstract

Electroporation is a physical process that consists in applying electric field pulses to transiently or permanently permeabilize the plasma membrane. This phenomenon is of great interest in the clinical field as well as in the industry because of its various applications, in particular electrochemotherapy which combines electrical pulses with the administration of a cytotoxic molecule in the treatment of tumors. The evaluation of this phenomenon is traditionally carried out using optical and biochemical methods (microscopy, flow cytometry, biochemical test). They are very effective but require the use of a wide range of fluorochromes and markers, which can be laborious and costly to implement, while being invasive to the cells. In recent years, the development of new biophysical tools for the study of electroporation has taken place, such as dielectrophoresis and impedance spectroscopy (low frequency). In addition to the ease of implementation, these methods are of interest in the study of membrane modifications of the cell. Hence the advantage of operating beyond the GHz, in the range of microwaves, for which the cytoplasmic membrane becomes transparent and the intracellular content is exposed. The extraction of the relative permittivity as a result of the electromagnetic field / biological cell interaction then reflects the cell state. This technique, microwave dielectric spectroscopy, is a relevant method for analyzing the effects of electroporation on cell viability. Moreover, it does not require any use of the exogenous molecules (non-invasive) and the measurements are directly carried out in the culture medium of the cells. Two objectives were defined during this thesis whose work is located at the interface between three scientific fields: cellular biology, microwave electronics and microtechnologies. The first objective concerns the transposition of conventional electroporation to the micrometric scale, which has shown an efficiency as efficient as the first. The second part of the work concerns the study by HighFrequency dielectric spectroscopy of cells subjected to different electrical treatments (combined or not with a cytotoxic molecule). This work presents a statistical power and shows a very good correlation (R2> 0.94) with standard techniques used in biology, which biologically validates the HF analysis method in the context of electroporation. This work also shows that microwave dielectric spectroscopy proves to be a powerful technique capable of revealing cell viability following chemical and / or electrical treatment. They open the way to 'non-invasive' analysis by hyper-frequency dielectric spectroscopy of electroporated cells in situ.

Résumé

L'électroporation est un procédé physique qui consiste à appliquer des impulsions de champ électrique pour perméabiliser de manière transitoire ou permanente la membrane plasmique. Ce phénomène est d'un grand intérêt dans le domaine clinique ainsi que dans l'industrie en raison de ses diverses applications, notamment l’électrochimiothérapie qui combine les impulsions électriques à l’administration d’une molécule cytotoxique, dans le cadre du traitement des tumeurs. L’analyse de ce phénomène est traditionnellement réalisée à l’aide des méthodes optique et biochimique (microscopie, cytométrie en flux, test biochimique). Elles sont très efficaces mais nécessitent l’utilisation d’une large gamme de fluorochromes et de marqueurs dont la mise en œuvre peut être laborieuse et coûteuse tout en ayant un caractère invasif aux cellules. Durant ces dernières années, le développement de nouveaux outils biophysiques pour l’étude de l’électroporation a pris place, tels que la diélectrophorèse et la spectroscopie d’impédance (basse fréquence). Outre une facilité de mise en œuvre, ces méthodes représentent un intérêt dans l’étude des modifications membranaires de la cellule. De là vient l’intérêt d’opérer au-delà du GHz, dans la gamme des micro-ondes, pour laquelle la membrane cytoplasmique devient transparente et le contenu intracellulaire est exposé. L’extraction de la permittivité relative suite à l’interaction champ électromagnétique/cellules biologiques reflète alors l’état cellulaire. Cette technique, la spectroscopie diélectrique hyperfréquence, se présente comme une méthode pertinente pour analyser les effets de l’électroporation sur la viabilité cellulaire. De plus, elle ne nécessite aucune utilisation des molécules exogènes (non-invasivité) et les mesures sont directement réalisées dans le milieu de culture des cellules. Deux objectifs ont été définis lors de cette thèse dont les travaux se situent à l’interface entre trois domaines scientifiques : la biologie cellulaire, l’électronique hyperfréquence et les micro-technologies. Le premier objectif concerne la transposition de l’électroporation conventionnelle à l’échelle micrométrique, qui a montré une efficacité aussi performante que la première. La deuxième partie du travail concerne l’étude par spectroscopie diélectrique HyperFréquence de cellules soumises à différents traitements électriques (combinés ou non à une molécule cytotoxique). Ces travaux présentent une puissance statistique et montrent une très bonne corrélation (R2 >0 .94) avec des techniques standards utilisées en biologie, ce qui valide ‘biologiquement’ la méthode d’analyse HF dans le contexte d’électroporation. Ces travaux montrent en outre que la spectroscopie diélectrique hyperfréquence s’avère être une technique puissante, capable de révéler la viabilité cellulaire suite à un traitement chimique et/ou électrique. Ils ouvrent la voie à l’analyse ‘non-invasive’ par spectroscopie diélectrique HyperFréquence de cellules électroporées in-situ.

Mots-Clés / Keywords
Analyse micro-onde; Electroporation; Biocapteur; Cellule unique; Microtechnologies; Perméabilisation membranaire; Spectroscopie diélectrique HyperFréquence;

139382
17060
09/02/2017

Banc de test des capteurs de gaz à semi-conducteurs

C.TALHI, P.MENINI, F.BLANC, B.FRANC

I2C, MICA, IDEA

Manifestation sans acte : Journée Scientifique - Présentation des travaux d'I2C ( ) 2017 du 09 février au 09 février 2017, Toulouse (France), Février 2017, 5p. , N° 17060

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139344
17028
01/02/2017

Microwave monitoring of single cell monocytes subjected to electroporation

A.TAMRA, D.DUBUC, M.P.ROLS, K.GRENIER

MH2F, IPBS

Revue Scientifique : IEEE Transactions on Microwave Theory and Techniques, 7p., Février 2017 , N° 17028

Lien : https://hal.laas.fr/hal-01463946

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Abstract

This paper presents the monitoring of single cells subjected to electroporation using microwave dielectric spectroscopy. The experimental results showed first a clear distinction between two cell states: viable cells and affected ones by a chemical treatment (Saponin). It also pointed out a high correlation (R 2 > 0.94) with biological standard techniques in detecting the two types of electroporation: the reversible and irreversible ones. The developed microfluidic and microwave-based sensor exposes a decrease in the capacitive and conductive contrasts of the investigated single cells treated by irreversible electroporation indicating damages at the cellular level, while cells under reversible electroporation present a similar dielectric response to that of the nontreated cells. This result corresponds to results frequently employed in biological studies. More interestingly , a study of the kinetics of the cell's damage induction over time, by electroporation, has been experimentally done, which makes microwave dielectric spectroscopy an attractive technique for cell's electroporation researches.

139097
17023
01/02/2017

Bacteria transfer by deformation through microfiltration membrane

A.GAVEAU, C.COETSIER, C.ROQUES, P.BACCHIN, E.DAGUE, C.CAUSSERAND

LGC, ELIA

Revue Scientifique : Journal of Membrane Science, Vol.523, pp.446-455, Février 2017 , N° 17023

Lien : https://hal.archives-ouvertes.fr/hal-01451400

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Abstract

Living particles such as bacteria are able to transfer through membrane pores that are smaller than cell size due to the specific stiffness of this type of microorganism. This phenomenon can lead to a significant loss of selectivity in the filtration process, which is a major cause of concern in the sterilizing filtration step. This study investigates the retention of three bacteria strains: Escherichia coli CIP 54124, Pseudomonas aeruginosa CIP 103467 and Staphylococcus aureus CIP 53154 by model porous membranes for various operating conditions (transmembrane pressure, feed concentration and the physicochemical composition of filtered media with antibacterial agent added at sublethal concentration). The first part of this study is dedicated to defining the size and the nanomechanical properties of the envelope of the studied bacteria by microscopic techniques (Transmission electron microscopy & Atomic-force microscopy), in order to then explore the role of these quantifiable characteristics on the cell transfer through the pores by deformation mechanisms. Our results lead to the development of a numerical model to connect the observed retention efficiency of the filtration experiment and the microscopic information about individual particles.

139060
16345
01/02/2017

Fabrication of lateral porous silicon membranes for planar microfluidics by means of ion implantation

Y.HE, T.LEICHLE

MEMS

Revue Scientifique : Sensors and Actuators B: Chemical, Vol.239, pp.628-634, Février 2017 , N° 16345

Non disponible

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Abstract

We introduce a new fabrication method based on ion implantation to create lateral porous silicon membranes and integrate them into planar microfluidic devices. Our proposed method relies on the fact that the formation of porous silicon by anodization highly depends on the dopant type and concentration, which can be manipulated by ion implantation. In order to confine the porosification at desired locations within silicon steps bridging microchannels, we use boron and phosphorus implantation to respectively create a p++ layer buried in an n-type silicon substrate, and a protective n-type surficial layer. The use of a metal electrode patterned onto the silicon step for current injection during anodization enables pores to propagate laterally during the membrane formation. The optimal implantation doses and energies leading to the required boron and phosphorus profiles are determined by means of process simulation and further confirmed by SIMS analysis. We demonstrate that the proposed fabrication process leads to the creation of lateral porous silicon membranes with open-ended pores adequately bridging microchannels and that we are able to manipulate the pore size (∼3–30 nm) and membrane porosity (∼15–65%) by adjusting the current density during anodization. The adequate dead-end filtration capability of the fabricated membranes was tested and demonstrates the interest of the presented fabrication process for microfluidic applications.

137837
17002
26/01/2017

Spray-coated carbon nanotube carpets for creeping reduction of conducting polymer based artificial muscles

A.SIMAITE, A.DELAGARDE, B.TONDU, P.SOUERES, E.FLAHAUT, C.BERGAUD

MEMS, ELIA, GEPETTO, CIRIMAT

Revue Scientifique : Nanotechnology, Vol.28, N°2, 025502p., Janvier 2017 , N° 17002

Lien : https://hal.laas.fr/hal-01413022

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Abstract

It is often observed that during cyclic actuation conducting polymer based artificial muscles are continuously creeping from the initial movement range. One of the likely reasons of such behaviour is unbalanced charging during conducting polymer oxidation and reduction. In order to improve the actuation reversibility and subsequently the long time performance of ionic actuators, we suggest to use spray-coated carbon nanotube (CNT) carpets on the surface of the conducting polymer electrodes. We show that carbon nanotubes facilitate conducting polymer redox reaction and improve its reversibility. Consequently, in the long term, charge accumulation in the polymer film is avoided leading to significantly improved long term performance during cycling actuation.

138654
16321
14/12/2016

High spatial resolution imaging of transient thermal events using materials with thermal memory

O.KRAIEVA, C.M.QUINTERO PINZON, I.SULEIMANOV, E.M.HERNANDEZ, D.LAGRANGE, L.SALMON, W.NICOLAZZI, G.MOLNAR, C.BERGAUD, A.BOUSSEKSOU

LCC, I2C, MEMS

Revue Scientifique : Small, Vol.12, N°46, pp.6325-6331, Décembre 2016 , N° 16321

Lien : https://hal.laas.fr/hal-01413097

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Abstract

The accurate control of temperature is a common requirement in science and technology. In particular, although much effort has been devoted in the past decade to the development of nanoscale thermometry methods, we currently lack the tools to map transient thermal events with high spatial resolution. Here we experimentally demonstrate the working principle of a new kind of nanothermometer using materials with thermal memory as time-temperature integrators. As an application, we tackle the outstanding problem of spatially resolving a brusque erratic heating event in an operating microelectronic device. We show that a spatially and temporally confined temperature change leads to a local (reversible) modulation of the optical properties of our material. Thanks to the virtually infinite lifetime of the metastable states within the bistability region, this optical information can be retrieved later on by a simple reflectivity measurement, either in far-or near-field. This concept enabled us to acquire sub-wavelength resolution images of transient (s scale) heating events. The recent tendency of miniaturization and achievements in nanoscience and nanotechnology brought about the necessity of accurate temperature measurements on a reduced size scale [1-4]. In addition, the heat exchange in tiny volumes occurs promptly, hence the measurement needs to be done most often in a limited time window. The lack of spatio-temporal resolution and the increasingly invasive nature of common temperature sensors are the main obstacles 1

138631
16474
09/12/2016

Comparative study of soft thermal printing and lamination of dry thick photoresist films for the uniform fabrication of polymer MOEMS on small-sized samples

S.ABADA, L.SALVI, R.COURSON, E.DARAN, B.REIG, J.B.DOUCET, T.CAMPS, V.BARDINAL

MICA, TEAM

Rapport LAAS N°16474, Décembre 2016, 19p.

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138520
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