Université PSL

Publications

RECHERCHER

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Nanorheology of Interfacial Water during Ice Gliding
Laboratoire Micromégas - Canale L., Comtet J., Nigu es A., Cohen C., Clanet C., Siria A., Bocquet L.
Nano Lett. - 19(10) 7265-7272 - doi.org/10.1021/acs.nanolett.9b02858 - 2019
Ionic current measurements through solid-state nanopores consistently show a power spectral density that scales as 1/f α at low frequency f, with an exponent α ∼ 0.5–1.5, but strikingly, the physical origin of this behavior remains elusive. Here, we perform simulations of particles reversibly adsorbing at the surface of a nanopore and show that the fluctuations in the number of adsorbed particles exhibit low-frequency pink noise. We furthermore propose theoretical modeling for the time-dependent adsorption of particles on the nanopore surface for various geometries, which predicts a frequency spectrum in very good agreement with the simulation results. Altogether, our results highlight that the low-frequency noise takes its origin in the reversible adsorption of ions at the pore surface combined with the long-lasting excursions of the ions in the reservoirs. The scaling regime of the power spectrum extends down to a cutoff frequency which is far smaller than simple diffusion estimates. Using realistic values for the pore dimensions and the adsorption–desorption kinetics, this predicts the observation of pink noise for frequencies down to the hertz for a typical solid-state nanopore, in good agreement with experiments.
Stress field inside the bath determines dip coating with yield-stress fluids in cylindrical geometry
Laboratoire MIE - Matériaux Innovants pour l'Energie - Wilbert J Smit, Christophe Kusina, Jean-François Joanny, Annie Colin
Phys. Rev. Lett. - 123(14) 148002 - - 2019
We study experimentally and theoretically the thickness of the coating obtained by pulling out a rod from a reservoir of yield-stress fluid. Opposite to Newtonian fluids, the coating thickness for a fluid of large enough yield stress is determined solely by the flow inside the reservoir and not by the flow inside the meniscus. The stress field inside the reservoir determines the thickness of the coating layer. The thickness is observed to increase nonlinearly with the sizes of the rod and of the reservoir. We develop a theoretical framework that describes this behavior and allows us to precisely predict the coating thickness.
Polymeric foams for flexible and highly sensitive low-pressure capacitive sensors
Laboratoire MIE - Matériaux Innovants pour l'Energie - Mickaël Pruvost, Wilbert J Smit, Cécile Monteux, Philippe Poulin, Annie Colin
npj Flexible Electronics - 1 7 - - 2019
Flexible low-pressure sensors (< 10 kPa) are required in areas as diverse as blood-pressure monitoring, human–computer interactions, robotics, and object detection. For applications, it is essential that these sensors combine flexibility, high sensitivity, robustness, and low production costs. Previous works involve surface micro-patterning, electronic amplification (OFET), and hydrogels. However, these solutions are limited as they involve complex processes, large bias voltages, large energy consumption, or are sensitive to evaporation. Here, we report a major advance to solve the challenge of scalable, efficient and robust e-skin. We present an unconventional capacitive sensor based on composite foam materials filled with conductive carbon black particles. Owing to the elastic buckling of the foam pores, the sensitivity exceeds 35 kPa− 1 for pressure< 0.2 kPa. These performances are one order of magnitude …
Chasing Aqueous Biphasic Systems from Simple Salts by Exploring the LiTFSI/LiCl/H2O Phase Diagram
Laboratoire MIE - Matériaux Innovants pour l'Energie - Nicolas Dubouis, Chanbum Park, Michael Deschamps, Soufiane Abdelghani-Idrissi, Matej Kanduč, Annie Colin, Mathieu Salanne, Joachim Dzubiella, Alexis Grimaud, Benjamin Rotenberg
ACS Central Science - 5 640-643 - - 2019
Aqueous biphasic systems (ABSs), in which two aqueous phases with different compositions coexist as separate liquids, were first reported more than a century ago with polymer solutions. Recent observations of ABS forming from concentrated mixtures of inorganic salts and ionic liquids raise the fundamental question of how “different” the components of such mixtures should be for a liquid–liquid phase separation to occur. Here we show that even two monovalent salts sharing a common cation (lithium) but with different anions, namely, LiCl and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), may result in the formation of ABSs over a wide range of compositions at room temperature. Using a combination of experimental techniques and molecular simulations, we analyze the coexistence diagram and the mechanism driving the phase separation, arising from the different anion sizes. The understanding and …
Inkjet Printing of Latex‐Based High‐Energy Microcapacitors
Laboratoire MIE - Matériaux Innovants pour l'Energie - Chasing Aqueous Biphasic Systems from Simple Salts by Exploring the LiTFSI/LiCl/H2O Phase Diagram N Dubouis, C Park, M Deschamps, S Abdelghani-Idrissi, M Kanduč, ... ACS Central Science 5 (4), 640-643
Advanced Functional Materials - 1901884 - - 2019
Microenergy storage devices are appealing and highly demanded for diverse miniaturized electronic devices, ranging from microelectromechanical system, robotics, to sensing microsystems and wearable electronics. However, making high‐energy microcapacitors with currently available printing technologies remains challenging. Herein, the possibility to use latex polyvinylidene fluoride (PVDF) as aqueous ink for making dielectric capacitors at the microscale is shown. The dielectric properties of printed microcapacitors can be optimized based on a novel approach, i.e., mixing PVDF latex with polyvinyl alcohol (PVA) to realize dielectric organic nanocomposites. The PVA prevents the coalescence of PVDF nanoparticles and serves as a continuous matrix phase with high dielectric breakdown strength. While the well‐dispersed PVDF nanoparticles serve as highly polarizable and isolated domains, providing large
A new way to measure viscosity in droplet-based microfluidics for high throughput analysis
Laboratoire MIE - Matériaux Innovants pour l'Energie - Estelle André, Nicolas Pannacci, Christine Dalmazzone, Annie Colin
Soft Matter - 3 504-514 - - 2019
In this work, we propose a new way to measure the viscosity of samples in a microfluidic device. By analysing the shape of droplets after an expansion, we can measure the viscosity of the phase inside the droplet knowing the surface tension between the two liquids, the flow rate, the geometry of the channel and the viscosity of the continuous phase. This work paves the way for future high throughput studies in the framework of digital microfluidics.
Parallelized DNA tethered bead measurements to scrutinize DNA mechanical structure
Laboratoire Physique des biomolécules - Allemand JF, Tardin C, Salomé L.
Nat. Methods - 1;169 46-56 - doi: 10.1016/j.ymeth.2019.07.020. - 2019
Tethering beads to DNA offers a panel of single molecule techniques for the refined analysis of the conformational dynamics of DNA and the elucidation of the mechanisms of enzyme activity. Recent developments include the massive parallelization of these techniques achieved by the fabrication of dedicated nanoarrays by soft nanolithography. We focus here on two of these techniques: the Tethered Particle motion and Magnetic Tweezers allowing analysis of the behavior of individual DNA molecules in the absence of force and under the application of a force and/or a torque, respectively. We introduce the experimental protocols for the parallelization and discuss the benefits already gained, and to come, for these single molecule investigations.
Anisotropic cellular forces support mechanical integrity of the Stratum Corneum barrier
Laboratoire Physique des biomolécules - Guo S, Domanov Y, Donovan M, Ducos B, Pomeau Y, Gourier C, Perez E, Luengo GS.
Chem. Mater - 92 45231 - doi: 10.1016/j.jmbbm.2018.12.027 - 2019
The protective function of biological surfaces that are exposed to the exterior of living organisms is the result of a complex arrangement and interaction of cellular components. This is the case for the most external cornified layer of skin, the stratum corneum (SC). This layer is made of corneocytes, the elementary 'flat bricks' that are held together through adhesive junctions. Despite the well-known protective role of the SC under high mechanical stresses and rapid cell turnover, the subtleties regarding the adhesion and mechanical interaction among the individual corneocytes are still poorly known. Here, we explore the adhesion of single corneocytes at different depths of the SC, by pulling them using glass microcantilevers, and measuring their detachment forces. We measured their interplanar adhesion between SC layers, and their peripheral adhesion among cells within a SC layer. Both adhesions increased considerably with depth. At the SC surface, with respect to adhesion, the corneocyte population exhibited a strong heterogeneity, where detachment forces differed by more than one order of magnitude for corneocytes located side by side. The measured detachment forces indicated that in the upper-middle layers of SC, the peripheral adhesion was stronger than the interplanar one. We conclude that the stronger peripheral adhesion of corneocytes in the SC favors an efficient barrier which would be able to resist strong stresses.
Anisotropic cellular forces support mechanical integrity of the Stratum Corneum barrier
Laboratoire Physique des biomolécules - Guo S, Domanov Y, Donovan M, Ducos B, Pomeau Y, Gourier C, Perez E, Luengo GS.
Chem. Mater - 92 45231 - doi: 10.1016/j.jmbbm.2018.12.027 - 2019
The protective function of biological surfaces that are exposed to the exterior of living organisms is the result of a complex arrangement and interaction of cellular components. This is the case for the most external cornified layer of skin, the stratum corneum (SC). This layer is made of corneocytes, the elementary 'flat bricks' that are held together through adhesive junctions. Despite the well-known protective role of the SC under high mechanical stresses and rapid cell turnover, the subtleties regarding the adhesion and mechanical interaction among the individual corneocytes are still poorly known. Here, we explore the adhesion of single corneocytes at different depths of the SC, by pulling them using glass microcantilevers, and measuring their detachment forces. We measured their interplanar adhesion between SC layers, and their peripheral adhesion among cells within a SC layer. Both adhesions increased considerably with depth. At the SC surface, with respect to adhesion, the corneocyte population exhibited a strong heterogeneity, where detachment forces differed by more than one order of magnitude for corneocytes located side by side. The measured detachment forces indicated that in the upper-middle layers of SC, the peripheral adhesion was stronger than the interplanar one. We conclude that the stronger peripheral adhesion of corneocytes in the SC favors an efficient barrier which would be able to resist strong stresses.
PICH and TOP3A cooperate to induce positive DNA supercoiling
Laboratoire Physique des biomolécules - Anna Hélène Bizard, Jean-Francois Allemand, Tue Hassenkam, Manikandan Paramasivam
Nature - 26(4) 1 - DOI: 10.1038/s41594-019-0201-6 - 2019
All known eukaryotic topoisomerases are only able to relieve torsional stress in DNA. Nevertheless, it has been proposed that the introduction of positive DNA supercoiling is required for efficient sister-chromatid disjunction by Topoisomerase 2a during mitosis. Here we identify a eukaryotic enzymatic activity that introduces torsional stress into DNA. We show that the human Plk1-interacting checkpoint helicase (PICH) and Topoisomerase 3a proteins combine to create an extraordinarily high density of positive DNA supercoiling. This activity, which is analogous to that of a reverse-gyrase, is apparently driven by the ability of PICH to progressively extrude hypernegatively supercoiled DNA loops that are relaxed by Topoisomerase 3a. We propose that this positive supercoiling provides an optimal substrate for the rapid disjunction of sister centromeres by Topoisomerase 2a at the onset of anaphase in eukaryotic cells.

391 publications.