Francoise Brochard-Wyart

Institut Curie · UMR 168 PCC Curie

The actin cytoskeleton shapes cells and also organizes internal membranous compartments. In particular, it interacts with membranes for intracellular transport of material in mammalian cells, yeast, or plant cells. Tubular membrane intermediates, pulled along microtubule tracks, are formed during this process and destabilize into vesicles. While th...

The actin cytoskeleton shapes cells and also organizes internal membranous compartments. In particular, it interacts with membranes in intracellular transport of material in mammalian cells, yeast or plant cells. Tubular membrane intermediates, pulled along microtubule tracks, are involved during these processes, and destabilize into vesicles. Whil...

Like The Magic Flute, my career has been paved by wonderful and unexpected stories played by enthusiastic and talented students, in close contact with experiments and industry. I participated in the birth of soft matter physics under the impulse of Pierre-Gilles de Gennes: polymers, liquid crystals, colloids, and wetting, which I later applied to t...

Significance The migration of cellular populations drives influential and disparate biological processes, from the establishment of embryos to the invasion of cancerous tissues. Its deregulation can lead to improper development or pathogenesis of diseases. While many of the mechanisms that promote single-cell migration have been identified, how cel...

The shape of cellular membranes is highly regulated by a set of conserved mechanisms that can be manipulated by bacterial pathogens to infect cells. Remodeling of the plasma membrane of endothelial cells by the bacterium Neisseria meningitidis is thought to be essential during the blood phase of meningococcal infection, but the underlying mechanism...

The sulfobetaine (SB) moiety, which comprises a quaternary ammonium group linked to a negatively-charged sulfonate ester, is known to impart non-fouling properties to interfaces coated with polysulfobetaines or grafted with SB-polymeric brushes. Increasingly, evidence emerges that the SB group is, overall, a better anti-fouling group than the phosp...

The shape of cellular membranes is highly regulated by a set of conserved mechanisms. These mechanisms can be manipulated by bacterial pathogens to infect cells. Human endothelial cell plasma membrane remodeling by the bacterium Neisseria meningitidis is thought to be essential during the blood phase of meningococcal infection, but the underlying m...

Controlling the propagation of primary tumors is fundamental to avoid the epithelial to mesenchymal transition process that leads to the dissemination and seeding of tumor cells throughout the body. Here, we demonstrate that nanoparticles (NPs) limit the propagation of aggregates of CT26 murine carcinoma cells used as tumor models. We studied the s...

Endometrial cancer (EC) is the sixth deadliest cancer in women. The depth of myometrial invasion is one of the most important prognostic factors, being directly associated with tumor recurrence and mortality. In this study, ALCAM, a previously described marker of EC recurrence, was studied by immunohistochemistry at the superficial and the invasive...

We study the spreading of cell aggregates deposited on adhesive substrates decorated with microparticles (MPs). A cell monolayer expands around the aggregate. The cells on the periphery of the monolayer take up the MPs, clearing the substrate as they progress and forming an aureole of cells filled with MPs. We study the dynamics of spreading and de...

We study the spreading on soft substrates of cellular aggregates by using CT26 cells that produce extracellular matrix (ECM). Compared to our previous work on the spreading of S180 cellular aggregates, which do not secrete ECM, we find that the spreading velocity of the precursor film is also maximal for intermediate rigidities, but new striking fe...

Endometrial cancer is the most common gynaecological cancer in western countries, being the most common subtype of endometrioid tumours. Most patients are diagnosed at an early stage and present an excellent prognosis. However, a number of those continue to suffer recurrence, without means of identification by risk classification systems. Thus, fin...

Tissues belong to the broad field of active matter, a novel class of non-equilibrium materials composed of many interacting units that individually consume energy and collectively generate motion or mechanical stresses. Active systems span an enormous range of length scales, from individual living cells, to tissues and organisms, to animal groups....

An article about our work can be found here! https://www.chemistryworld.com/news/nanoplasters-get-cells-into-sticky-situation/1017425.article We present direct evidence that nanoparticles (NPs) can stick together cells that are inherently non-adhesive. Using cadherin-depleted S180 murine cells lines, which exhibit very low cell–cell adhesion, we s...

Both cells and ants belong to the broad field of active matter, a novel class of non-equilibrium materials composed of many interacting units that individually consume energy and collectively generate motion or mechanical stresses. However cells and ants differ from fish and birds in that they can support static loads. This is because cells and ant...

Cell-shape changes are insured by a thin, dynamic, cortical layer of cytoskeleton underneath the plasma membrane. How this thin cortical structure impacts the mechanical properties of the whole cell is not fully understood. Here, we study the mechanics of liposomes or giant unilamellar vesicles, when a biomimetic actin cortex is grown at the inner...

Aquaporin 0 (AQP0) is a transmembrane protein specific to the eye lens, involved as a water carrier across the lipid membranes. During eye lens maturation, AQP0s are truncated by proteolytic cleavage. We investigate in this work the capability of truncated AQP0 to conduct water across membranes. We developed a method to accurately determine water p...

Membrane tubes are commonly extruded from cells and vesicles when a point-like force is applied on the membrane. In contrast, we report here the formation of membrane tubes from Lymph Node Cancer Prostate (LNCaP) cell aggregates in the absence of external applied forces. The spreading of LNCaP aggregates deposited on adhesive glass substrates coate...

Hydrophilic (glassy) films of polyvinylpyrrolidone (PVP) are deposited on glass slides (or on silicon wafers). The films are then swollen by immersion in a good solvent, or by cooling in a damp atmosphere. Thermoplastic ¯lms remain smooth upon swelling. Cross-linked films show a pattern of surface fractures and ripples, if their thickness e is beyo...

Significance Cellular aggregates are in vitro model of tumors. Deposited on adhesive substrates, they spread like liquid droplets with a monolayer expanding from the aggregate. We model spreading dynamics by balancing driving forces at the film periphery and viscous forces associated to the penetration of the cells from the (3D) aggregate into the...

We propose a novel characterization method of randomly branched polymers based on the geometrical property of such objects in confined spaces. The central idea is that randomly branched polymers exhibit passing/clogging transition across the nano-channel as a function of the channel size. This critical channel size depends on the degree of the bran...

We first describe the biomechanics of multicellular aggregates, a model system for tissues and tumors. We first characterize the tissue mechanical properties (surface tension, elasticity, viscosity) by a new pipette aspiration technique. The aggregate exhibits a viscoelastic response but, unlike an inert fluid, we observe aggregate reinforcement wi...

The dynamics of cellular adhesion and deadhesion, which play key roles in many cellular processes, have most often been studied at the scale of single bonds or single cells. However, multicellular adhesion and deadhesion are also central processes in tissue mechanics, morphogenesis, and pathophysiology, where collective tissue phenomena may introdu...

We describe the biomechanics of multicellular aggregates, a model system for tissues and tumors. We first characterize the tissue mechanical properties (surface tension, elasticity, viscosity) by a new pipette aspiration technique. The aggregate exhibits a viscoelastic response but, unlike an inert fluid, we observe aggregate reinforcement with pre...

Dewetting is the spontaneous withdrawal of a liquid film from a non-wettable surface by nucleation and growth of dry patches. Two recent reports now propose that the principles of dewetting explain the physical phenomena underpinning the opening of transendothelial cell macroaperture (TEM) tunnels, referred to as cellular dewetting. This was discov...

Analogies with inert soft condensed matter—such as viscoelastic liquids, pastes, foams, emulsions, colloids, and polymers—can be used to investigate the mechanical response of soft biological tissues to forces. A variety of experimental techniques and biophysical models have exploited these analogies allowing the quantitative characterization of th...

We examine the spreading of cellular aggregates deposited on adhesive striated glass surfaces consisting of 100μm large bands alternatively coated with fibronectin and with PolyEthyleneGlycol-Poly-L-lysine (PEG-PLL). The aggregates spread confined to the adhesive fibronectin bands. A front of cells expands from the aggregate at constant velocity. I...

We report new experimental results on the dewetting of a mercury film (A) intercalated between a glass slab and an external non-miscible liquid phase (B), in conditions of large equilibrium contact angle. The viscosity of the external phase, η(B), was varied over seven orders of magnitude. We observe a transition between two regimes of dewetting at...

Induced spontaneous curvature is a new mechanism of microcapsules bursting by nucleation and growth of a hole surrounded by a curling rim. Here we study the dynamics of curling on a macroscopic scale induced by the elastic curvature of a bilayer of tracing paper and tape after soaking by water. The ribbon which is fully stretched at time t = 0 is i...

Pathogenic bacteria can cross from blood vessels to host tissues by opening transendothelial cell macroapertures (TEMs). To induce TEM opening, bacteria intoxicate endothelial cells with proteins that disrupt the contractile cytoskeletal network. Cell membrane tension is no longer resisted by contractile fibers, leading to the opening of TEMs. Here...

We investigate the physical principles of cellular layer stability. We show that cohesive cellular layers deposited on non-adhesive substrates are metastable and "dewet" by nucleation and growth of dry patches. The dewetting process can be induced either chemically by a non-adhesive surface treatment or, unlike simple liquids, physically by a decre...

The inhibition of tissue spreading is of great interest for medical applications, including the prevention of tumor mass dispersal to avoid cancer propagation. While chemical approaches have previously been reported to control tissue spreading, here we investigate a physical mechanism to inhibit spreading. We study the effect of substrate rigidity...

Biological self-assembly is a useful tool to build living tissues for medical applications or in vitro studies. Here we investigate the ability of cells to self-organize and construct three-dimensional cellular structures on non-adhesive substrates. When cells are deposited on a PolyEthyleneGlycol-coated substrate, they diffuse randomly and eventua...

We study the kinetics of specific adhesion of giant vesicles on complemetary (bilayer-decorated) solid surfaces. Tensed vesicles exhibit a single adhesion zone that grows slowly. Floppy vesicles adhere via many small adhesion spots that grow and fuse, merging finally into a large adhesive zone. Using approaches derived from Ref. 12, we show how the...

RhoA-inhibitory bacterial toxins, such as Staphylococcus aureus EDIN toxin, induce large transendothelial cell macroaperture (TEM) tunnels that rupture the host endothelium barrier and promote bacterial dissemination. Host cells repair these tunnels by extending actin-rich membrane waves from the TEM edges. We reveal that cyclic-AMP signaling produ...

Tissue spreading is a fundamental process in embryonic development, wound healing, and cancer invasion. We study the spreading dynamics of cell aggregates on solid substrates by means of an analogy with the wetting of a viscoelastic drop. At long times, a precursor film of cells spreads around the aggregate with two possible states: either a liquid...

We report on the role of a surfactant monolayer in the impact of small spheres on an air-water interface. We observe that an air cavity (splashing) is induced above a threshold impact velocity. We explore the dependence of this threshold velocity on the bath surface tension and on the bath viscosity using water-ethanol and water-glycerol mixtures,...

During embryonic development and wound healing, the mechanical signals transmitted from cells to their neighbors induce tissue rearrangement and directional movements. It has been observed that forces exerted between cells in a developing tissue under stress are not always monotonically varying, but they can be pulsatile. Here we investigate the re...

A non adsorbing, flexible polymer (in dilute solution with a good solvent)enters a pore (of diameter D smaller than its natural size R F only when it is sucked in by a solvent flux J higher than a threshold value J c . For linear polymers \(J_c \simeq kT/\eta \) (whereT is the temperature and η the solvent viscosity). We discuss here the case of st...