Matière et Systèmes Complexes

MSC 7057

Tutelles >

Université Paris Diderot

UFR de rattachement >

UFR Physique

Label unité >

UMR 7057

Partenaires >

CNRS

Présentation

Le laboratoire « Matière et Systèmes Complexes » (MSC) est une unité mixte de recherche du CNRS et de l’université (UMR 7057). Le laboratoire est installé depuis 2007 sur le nouveau campus de l’Université Paris Diderot, Paris Rive Gauche, dans le bâtiment Condorcet. Il est réparti sur plusieurs étages. La direction et le secrétariat se trouvent au 6e étage. Le directeur actuel en est Laurent Limat, secondé par la directrice adjointe Florence Gazeau.

Le laboratoire MSC a pour sujet d’étude la matière et les systèmes complexes sous toutes leurs formes. Il peut s’agir de fluides montrant des phénomènes complexes non-linéaires (facettages de jets ou de tourbillons, structures et propriétés complexes de mousses, phénomènes de mouillage, propagation de vagues et de tsunamis) ou bien, par exemple, de systèmes proches de la géophysique et de l’environnement (systèmes granulaires tels que les dunes, phénomènes d’érosion, morphogenèse des plantes et même des villes, nage collective d’algues ou de bactéries…). Les études théoriques et expérimentales conduisent à des applications comme par exemple les éoliennes flexibles de haut rendement, l’optimisation de méthodes d’enduisage, le contôle de propriétés de surface ou la récupération de la biomasse (ingénierie verte)...

Le laboratoire étudie également le couplage entre la physique et la biologie des systèmes vivants, avec une approche multi-échelle. Les recherches effectuées vont d’échelles moléculaires ou supra-moléculaires (assemblages des protéines, chromatine, cytosquelette etc.) jusqu’à l’échelle de l’organisme entier (méduses, poulets, vers etc.) en passant par des études plus fondamentales sur des cellules uniques sur lesquelles sont exercées des forces quantifiées, permettant de comprendre les propriétés biophysiques de la matière vivante. Ces études aboutissent à de possibles applications en ingénierie tissulaire ou régénération des tissus avec des transferts dans le domaine médical.

Equipes de recherche

Le laboratoire est structuré en cinq équipes :

Dynamique des systèmes hors d’équilibre (DSHE), orientée plutôt vers les comportements non-linéaires de fluides, éventuellement actifs ou avec surface libre, et les phénomènes d’auto-organisation en général (morphogenèse des granulaires, systèmes particulaires inspirés de la matière condensée, colloïdes et transition d’encombrement, etc).
Dynamique et organisation de la matière molle (DOMM), orientée plutôt vers les matériaux mous visco-élastiques aux propriétés rhéologiques complexes (gels, polymères, mousses etc.), milieux caractérisés par une structure hétérogène, et dont l’organisation et les propriétés dépendent de l’échelle d’observation.
Physique du vivant, orientée plutôt vers l’étude des processus physiques qui sous-tendent les fonctions biologiques, principalement à l’échelle cellulaire, entre la molécule et le tissu.
Biofluidique, orientée plutôt vers l’étude des systèmes vivants du tissu à l’organisme, avec des applications à visées médicales.
Une équipe de théoriciens dont les thématiques couvrent un spectre large de questions fondamentales allant de la physique statistique hors équilibre à la neuroscience, en passant par la matière molle et la matière active.

Cependant les activités de ces équipes se recoupent souvent dans des projets communs aux frontières entre les comportements physiques et/ou biologiques (exemple : comportement de mousses marines, mesures de forces dans des tissus reconstitués, etc.)

[inserm-00336932] In vivo imaging of transplanted hepatocytes with a 1.5-T clinical MRI system--initial experience in mice.

Date: 5 Nov 2008 - 15:16

Desc: The feasibility of in vitro mature mouse hepatocyte labeling with a novel iron oxide particle was assessed and the ability of 1.5-T magnetic resonance imaging (MRI) to track labeled mouse hepatocytes in syngenic recipient livers following intraportal cell transplantation was tested. Mouse hepatocytes were incubated with anionic iron oxide nanoparticles at various iron concentrations. Cell viability was assessed and iron oxide particle uptake quantified. Labeled hepatocytes were intraportally injected into 20 mice, while unlabeled hepatocytes were injected into two mice. Liver T2 values, spleen-to-muscle relative signal intensity (RI( spleen/muscle )), and liver-to-muscle relative signal intensity (RI( liver/muscle )) on gradient-echo T2-weighted imaging after injection of either labeled or unlabeled hepatocytes were compared with an ANOVA test followed by Fisher's a posteriori PLSD test. Livers, spleens and lungs were collected for histological analysis. Iron oxide particle uptake was saturable with a maximum iron content of 20 pg per cell and without viability alteration after 3 days of culture. Following labeled-cell transplantation, recipient livers showed well-defined nodular foci of low signal intensity on MRI--consistent with clusters of labeled hepatocytes on pathological analysis--combined with a significant decrease in both liver T2 values and liver-to-muscle RI( liver/muscle ) (P = 0.01) with minimal T2 values demonstrated 8 days after transplantation. Conventional MRI can demonstrate the presence of transplanted iron-labeled mature hepatocytes in mouse liver.

[hal-02400112] Mechanical behaviour of contractile gels based on light-driven molecular motors

Date: 20 Mar 2023 - 10:29

Desc: The networking of individual artificial molecular motors into collective actuation systems is a promising approach for the design of active materials working out of thermodynamic equilibrium. Here, we report the first mechanical studies on active polymer gels built by integrating light-driven rotary molecular motors as reticulation units in polymer networks. We correlate the volume ratio before and after light irradiation with the change of the elastic modulus, and we reveal the universal maximum mechanical efficiency of such gels related to their critical overlap concentration before chemical reticulation. We also show the major importance of heterogeneities in the macroscopic contraction process and we confirm that these materials can increase their internal energy by the motorized winding of their polymer chains.

[hal-04030600] Information stored in Faraday waves: the origin of a path memory

Date: 15 Mar 2023 - 15:53

Desc: On a vertically vibrating fluid interface, a droplet can remain bouncing indefinitely. When approaching the Faraday instability onset, the droplet couples to the wave it generates and starts propagating horizontally. The resulting wave–particle association, called a walker, was shown previously to have remarkable dynamical properties, reminiscent of quantum behaviours. In the present article, the nature of a walker's wave field is investigated experimentally, numerically and theoretically. It is shown to result from the superposition of waves emitted by the droplet collisions with the interface. A single impact is studied experimentally and in a fluid mechanics theoretical approach. It is shown that each shock emits a radial travelling wave, leaving behind a localized mode of slowly decaying Faraday standing waves. As it moves, the walker keeps generating waves and the global structure of the wave field results from the linear superposition of the waves generated along the recent trajectory. For rectilinear trajectories, this results in a Fresnel interference pattern of the global wave field. Since the droplet moves due to its interaction with the distorted interface, this means that it is guided by a pilot wave that contains a path memory. Through this wave-mediated memory, the past as well as the environment determines the walker's present motion.

[hal-02565552] A frugal implementation of Surface Enhanced Raman Scattering for sensing Zn2+ in freshwaters – In depth investigation of the analytical performances

Date: 11 Dic 2021 - 07:46

Desc: Surface Enhanced Raman Scattering (SERS) has been widely praised for its extreme sensitivity but has not so far been put to use in routine analytical applications, with the accessible scale of measurements a limiting factor. We report here on a frugal implementation of SERS dedicated to the quantitative detection of Zn2+ in water, Zn being an element that can serve as an indicator of contamination by heavy metals in aquatic bodies. The method consists in randomly aggregating simple silver colloids in the analyte solution in the presence of a complexometric indicator of Zn2+, recording the SERS spectrum with a portable Raman spectrometer and analysing the data using multivariate calibration models. The frugality of the sensing procedure enables us to acquire a dataset much larger than conventionally done in the field of SERS, which in turn allows for an in-depth statistical analysis of the analytical performances that matter to end-users. In pure water, the proposed sensor is sensitive and accurate in the 160–2230 nM range, with a trueness of 96% and a precision of 4%. Although its limit of detection is one order of magnitude higher than those of golden standard techniques for quantifying metals, its sensitivity range matches Zn levels that are relevant to the health of aquatic bodies. Moreover, its frugality positions it as an interesting alternative to monitor water quality. Critically, the combination of the simple procedure for sample preparation, abundant SERS material and affordable portable instrument paves the way for a realistic deployment to the water site, with each Zn reading three to five times cheaper than through conventional techniques. It could therefore complement current monitoring methods in a bid to solve the pressing needs for large scale water quality data.

[hal-03795695] Surface tension of model tissues during malignant transformation and epithelial–mesenchymal transition

Date: 4 Oct 2022 - 11:44

Desc: Epithelial–mesenchymal transition is associated with migration, invasion, and metastasis. The translation at the tissue scale of these changes has not yet been enlightened while being essential in the understanding of tumor progression. Thus, biophysical tools dedicated to measurements on model tumor systems are needed to reveal the impact of epithelial–mesenchymal transition at the collective cell scale. Herein, using an original biophysical approach based on magnetic nanoparticle insertion inside cells, we formed and flattened multicellular aggregates to explore the consequences of the loss of the metastasis suppressor NME1 on the mechanical properties at the tissue scale. Multicellular spheroids behave as viscoelastic fluids, and their equilibrium shape is driven by surface tension as measured by their deformation upon magnetic field application. In a model of breast tumor cells genetically modified for NME1, we correlated tumor invasion, migration, and adhesion modifications with shape maintenance properties by measuring surface tension and exploring both invasive and migratory potential as well as adhesion characteristics.