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.)

[hal-00783009] Lithium-ion battery electrode prepared by confining carbon nanotubes/V2O5 nanoribbons suspension in model aireliquid foams

Date: 31 Ene 2013 - 10:24

Desc: Well-defined macroporous V2O5eCNTs hybrid solid foams are synthesized in the form of monolith by a controlled bubbling process. For the first time, the solid phase results from the co-assembly of two different anisotropic nano-building blocks in the continuous phase of model foams whose bubble size and liquid fraction could be tuned. Their electrochemical properties were examined in view of their application as cathode for Li-ion battery. This first investigation revealed that capacity up to 250 mAh g-1 (i.e. 2 Li per V2O5) can be attain with a good retention under cycles when CNTs are present making these new cellular materials interesting candidate for systems which require the penetration of viscous ionic-liquid/polymer electrolytes.

[tel-03095708] An in vitro model for the mouse Epiblast to investigate the establishment of the antero-posterior polarity.

Date: 4 Ene 2021 - 17:12

Desc: The development of an embryo is an interplay of phenomena, involving morphogenetic rearrangements, collective migration and cell differentiation. How a complex shape, made of many different tissues, arises from a symmetric pool of identical cells is still not fully unveiled. In this thesis, we are interested in understanding one of the first events that breaks the symmetry of the embryo and establishes a direction along which, the different tissues of the future body will be allocated: the establishment of the Antero-Posterior polarity (A-P), that will mark the locus at will gastrulation will start. How this axis is established has been partly elucidated. We know that the process is controlled by some chemical signalling, morphogens, released by some subgroups of cells in the extra-embryonic tissue. The minimal conditions for observing polarity however are still not clear. With this work we intend to build a synthetic in vitro system to find out the minimal ingredients to observe symmetry breaking in a symmetrical structure, that mimics the Epiblast in morphology and gene expression. We observe how this system reacts under homogeneous stimulation with morphogens. We compare the results obtained, to a situation where the symmetry of the stimulus is broken. To feed the cells with a directional stimulus, we make use of microfluidics: we developed a device that allows us to stimulate our synthetic Epiblast with a gradient of morphogens. Our original device was relying on continuous flow to establish a perfect sink and source to maintain the gradient. We observed a loss of Nodal expression that we did not observe when stimulating the organoids in bulk. We hypothesise the continuous flow to be accountable for washing out some secreted signalling downstream of the signal we induce differentiation with. By modifying the device to induce a uniform stimulation, but producing a gradient of secreted molecules, we were able to observe polarity arising in the organoids in a more consistent way than in bulk. We conclude that these experiments hint to the existence of a self-regulated mechanism in the embryo to establish polarity, and that this mechanism co-operate with others to ensure the robustness of the polarisation, and that a localised source of signalling molecules could be relevant to increase the frequency of observation of polarity in Embryonic Stem Cells only organoids. We anticipate that further studies making use of static gradients devices would allow to push this result further. Last, we propose a system that would allow the study of an underinvestigated aspect of development: the role pf physical confinement. As seen, the early embryo is confined by the Extra-embryonic tissue, applying a constraint to it. We suggest that it would be interesting to study the confinement aspect, uncoupling it from the signalling aspect. To do so, we propose to adapt an encapsulation method originally developed to grow cancer cells organoids, to encapsulate Embryonic Stem Cells.

[hal-01196599] The formation of ordered nanoclusters controls cadherin anchoring to actin and cell-cell contact fluidity

Date: 10 Sep 2015 - 11:39

Desc: Oligomerization of cadherins could provide the stability to ensure tissue cohesion. Cadherins mediate cell-cell adhesion by forming trans-interactions. They form cis-interactions whose role could be essential to stabilize intercellular junctions by shifting cadherin clusters from a fluid to an ordered phase. However, no evidence has been provided so far for cadherin oligomerization in cellulo and for its impact on cell-cell contact stability. Visualizing single cadherins within cell membrane at a nanometric resolution, we show that E-cadherins arrange in ordered clusters, providing the first demonstration of the existence of oligomeric cadherins at cell-cell contacts. Studying the consequences of the disruption of the cis-interface, we show that it is not essential for adherens junction formation. Its disruption, however, increased the mobility of junctional E-cadherin. This destabilization strongly affected E-cadherin anchoring to actin and cell-cell rearrangement during collective cell migration, indicating that the formation of oligomeric clusters controls the anchoring of cadherin to actin and cell-cell contact fluidity.

[hal-01461528] Matière condensée : organisation et dynamique

Date: 8 Feb 2017 - 11:24

Desc: no abstract

[hal-00840804] Capillary force on a micrometric sphere trapped at a fluid interface exhibiting arbitrary curvature gradients

Date: 4 Jun 2021 - 12:30

Desc: We report theoretical predictions and measurements of the capillary force acting on a spherical colloid smaller than the capillary length that is placed on a curved uid interface of arbitrary shape. By coupling direct imaging and interferometry, we are able to measure the in situ colloid contact angle and to correlate its position with respect to the interface curvature. Extremely tiny capillary forces down to femto-Newton can be measured with this method. Measurements agree well with a theory relating the capillary force to the gradient of Gaussian curvature and to the mean curvature of the interface prior to colloidal deposition. Numerical calculations corroborate these results.