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Matière Molle
(423) Articles dans des revues
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Microfluidic Study of Enhanced Deposition of Sickle Cells at Acute Corners
Auteur(s): Massiera G., Loiseau E., Mendez Simon, Aguilar-Martinez Patricia, Abkarian M.
(Article) Publié:
Biophysical Journal, vol. 108 p.2623–2632 (2015)
Texte intégral en Openaccess :
Ref HAL: hal-01164311_v1
PMID 26039164
DOI: 10.1016/j.bpj.2015.04.018
WoS: 000355668800004
Exporter : BibTex | endNote
14 Citations
Résumé: Sickle cell anemia is a blood disorder, known to affect the microcirculation and is characterized by painful vaso-occlusive crises in deep tissues. During the last three decades, many scenarios based on the enhanced adhesive properties of the membrane of sickle red blood cells have been proposed, all related to a final decrease in vessels lumen by cells accumulation on the vascular walls. Up to now, none of these scenarios considered the possible role played by the geometry of the flow on deposition. The question of the exact locations of occlusive events at the microcirculatory scale remains open. Here, using microfluidic devices where both geometry and oxygen levels can be controlled, we show that the flow of a suspension of sickle red blood cells around an acute corner of a triangular pillar or of a bifurcation, leads to the enhanced deposition and aggregation of cells. Thanks to our devices, we follow the growth of these aggregates in time and show that their length does not depend on oxygenation levels; instead, we find that their morphology changes dramatically to filamentous structures when using autologous plasma as a suspending fluid. We finally discuss the possible role played by such aggregates in vaso-occlusive events.
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Droplet Liquid/Liquid Interfaces Generated in a Microfluidic Device for Assembling Janus Inorganic Nanohybrids
Auteur(s): Hassan Natalia, Stocco A., Abou-Hassan Ali
(Article) Publié:
The Journal Of Physical Chemistry C, vol. 119 p.10758–10765 (2015)
Ref HAL: hal-01163692_v1
DOI: 10.1021/acs.jpcc.5b02527
WoS: 000354912200069
Exporter : BibTex | endNote
22 Citations
Résumé: One among other remarkable methods to produce multifunctional assemblies with different spatial organizations is the use of liquid–liquid (L–L) interfaces. Herein, a droplet microfluidic-based method is reported as a strategy for the assembly of asymmetrical inorganic nanohybrid structures. As a proof of concept and motivated by their wide applications in different fields, we studied the assembly of two building nanoblocks, which are fluorescent silica (160 nm diameter) and gold nanoparticles (15 nm diameter). In this strategy, droplets of an aqueous solution of citrated gold nanoparticles are generated in a continuous flow of amine functionalized fluorescent silica nanoparticles dispersed in cyclohexane using the microdevice. The electrostatic attraction between the two nanoparticles confined at the water/cyclohexane interface to form a Pickering emulsion allowed their assembly. We show that Janus nanohybrids can only be observed when the residence time in the microdevice was less than 30 min, thus avoiding the formation of solid shells for longer residence times. Transmission and scanning electron microscopies, optical microscopies, and UV–vis spectroscopy were used to characterize the resulting assemblies. The results were compared to experiments in bulk which showed that microfluidics offers a higher control over the assembly and reduces the time for their elaboration. Moreover, an analytical model based on transport of nanoparticles and their adsorption onto interfaces is used to rationalize our observations. Both flow recirculation inside and outside the droplets in the microchannel and the confinement effect seem to be relevant for the enhanced nanoparticle transport to the interfaces.
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Electrostatic Interaction between Nonuniformly Charged Colloids: Experimental and Numerical Study
Auteur(s): Derot Claire, Porcar Lionel, Lee Yongjin, Pincus Phillip A., Jho Yongseok, In M.
(Article) Publié:
Langmuir, vol. 31 p.1649 (2015)
Ref HAL: hal-01148771_v1
DOI: 10.1021/la504579c
WoS: 000349575200007
Exporter : BibTex | endNote
1 Citation
Résumé: The influence of the surface charge distribution on the interaction between nanosized particles in water is reported. The distribution of charges at the surface of initially neutral microemulsion droplets has been modulated by additions of various oligomeric cationic surfactants. The osmotic compressibility of the doped microemulsions was measured by light and small-angle neutrons scattering and reveals that the overall effective interaction induced by the ionic groups is repulsive. However, particular charge distributions decrease the osmotic compressibility much less than others. Independent measurements of the activity of the bromide counterions with specific electrodes evidence a significant decrease in the effective charge, which, however, cannot account for the osmotic compressibility in the framework of the primitive model. The q dependence of the structure factor reveals an attractive contribution over a short distance. Numerical studies assign this attractive contribution to the overlap of hydration shells that are extended as a result of the charge localization.
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Vibration of low amplitude imaged in amplitude and phase by sideband versus carrier correlation digital holography
Auteur(s): Verrier N., Alloul L, Gross M.
(Article) Publié:
Optics Letters, vol. 40 p.411 - 414 (2015)
Texte intégral en Openaccess :
Ref HAL: hal-01111198_v1
Ref Arxiv: 1501.07555
DOI: 10.1364/OL.40.000411
WoS: 000349162000030
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
6 Citations
Résumé: Sideband holography can be used to get fields images (E0 and E1) of a vibrating object for both the carrier (E0) and the sideband (E1) frequency with respect to vibration. We propose here to record E0 and E1 sequentially, and to image the correlation E1E * 0 . We show that this correlation is insensitive the phase related to the object roughness and directly reflect the phase of the mechanical motion. The signal to noise can be improved by averaging the correlation over neighbor pixel. Experimental validation is made with vibrating cube of wood and with a clarinet reed. At 2 kHz, vibrations of amplitude down to 0.01 nm are detected.
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Thermally sensitive reversible microgels formed by poly(N-Isopropylacrylamide) charged chains: A Hofmeister effect study
Auteur(s): Lopez-Leon T., Ortega-Vinuesa Juan, Bastos-González Delfi, Elaissari Abdelhamid
(Article) Publié:
Journal Of Colloid And Interface Science, vol. 426 p.300-307 (2014)
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Curling and rolling dynamics of naturally curved ribbons
Auteur(s): Albarran O., Massiera G., Abkarian M.
(Article) Publié:
Soft Matter, vol. 10 p.3055-3065 (2014)
Ref HAL: hal-02069034_v1
DOI: 10.1039/C3SM52142G
WoS: 000334494000016
Exporter : BibTex | endNote
7 Citations
Résumé: When a straight rod is bent and suddenly released on one end, a burst of dispersive flexural waves propagates down the material as predicted by linear beam theories. However, we show that for ribbons with a longitudinal natural radius of curvature a0, geometrical constraints lead to strain localization which controls the dynamics. This localized region of deformation selects a specific curling deformation front which travels down the ribbon when initially flattened and released. Performing experiments on different ribbons, in air and in water, we show that initially, on length scales on the order of a0, the curling front moves as a power law of time with an exponent ranging from 0.5 to 2 for increasing values of the ribbons' width. At longer time scales, the material wraps itself at a constant speed Vr into a roll of radius R ≠ a0. The relationship between Vr and R is calculated by a balance between kinetic, elastic and gravitational energy and both internal and external powers dissipated. When gravity and drag are negligible, we observe that a0/R reaches a limiting value of 0.48 that we predict by solving the Elastica on the curled ribbon considering the centrifugal forces due to rotation. The solution we propose represents a solitary traveling curvature wave which is reminiscent to propagating instabilities in mechanics.
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Red blood cell: from its mechanics to its motion in shear flow
Auteur(s): Viallat A., Abkarian M.
(Article) Publié:
International Journal Of Laboratory Hematology, vol. 36 p.237-243 (2014)
Texte intégral en Openaccess :
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