A5040298003- Cellular Mechanics and Interactions
- Liquid Crystal Research Advancements
- Micro and Nano Robotics
- Lipid Membrane Structure and Behavior
- Advanced Thermodynamics and Statistical Mechanics
- Microtubule and mitosis dynamics
- Force Microscopy Techniques and Applications
- Microfluidic and Bio-sensing Technologies
- 3D Printing in Biomedical Research
- stochastic dynamics and bifurcation
- Advanced Materials and Mechanics
- Nonlinear Dynamics and Pattern Formation
- Molecular spectroscopy and chirality
- Protein Structure and Dynamics
- Surfactants and Colloidal Systems
- Material Dynamics and Properties
- Spectroscopy and Quantum Chemical Studies
- Theoretical and Computational Physics
- Cellular transport and secretion
- Biocrusts and Microbial Ecology
- Spaceflight effects on biology
- Plant Reproductive Biology
- Nanopore and Nanochannel Transport Studies
- Photoreceptor and optogenetics research
- Electrostatics and Colloid Interactions
Institut Curie
2015-2024
Sorbonne Université
2014-2024
Université Paris Sciences et Lettres
2015-2024
National University of Singapore
2015-2024
Centre National de la Recherche Scientifique
2014-2023
Physique des Cellules et Cancers
2010-2022
Max Planck Institute for the Physics of Complex Systems
2002-2022
TU Dresden
2022
ESPCI Paris
2005-2020
ParisTech
2009-2020
Part 1 Liquid crystals - main types and properties: introduction what is a liquid crystal? the building blocks nematics cholesterics smectics columnar phases more on long-, quasi-long short-range order remarkable features of crystals. 2 Long- in nematics: definition an parameter statistical theories nematic phenomonological description nematic-isotopic mixtures. 3 Static distortion single crystal: principles continuum theory magnetic field effects electric insulating fluctuations alignment...
This review summarizes theoretical progress in the field of active matter, placing it context recent experiments. approach offers a unified framework for mechanical and statistical properties living matter: biofilaments molecular motors vitro or vivo, collections motile microorganisms, animal flocks, chemical imitations. A major goal this is to integrate several approaches proposed literature, from semimicroscopic phenomenological. In particular, first considered are ``dry'' systems, defined...
The authors present general considerations and simple models for the operation of isothermal motors at small scales, in asymmetric environments. Their work is inspired by recent observations on behavior molecular biological realm, where chemical energy converted into mechanical energy. A generic Onsager-like description linear (close to equilibrium) regime presented, which exhibits structural differences from usual Carnot engines. Turning more explicit a single motor, show importance time...
We develop a general theory for active viscoelastic materials made of polar filaments. This is motivated by the dynamics cytoskeleton. The continuous consumption fuel generates nonequilibrium state characterized generation flows and stresses. Our applies to any system with internal energy such as chemical gels cytoskeletal networks which are set in motion processes at work cells.
We show that the formation of membrane tubes (or tethers), which is a crucial step in many biological processes, highly nontrivial and involves first-order shape transitions. The force exerted by an emerging tube nonmonotonic function its length. point out attract each other, eventually leads to their coalescence. also detached behave like semiflexible filaments with rather short persistence suggest these properties play important role structure tubular organelles.
During the formation of tissues, cells organize collectively by cell division and apoptosis. The multicellular dynamics such systems is influenced mechanical conditions can give rise to rearrangements movements. We develop a continuum description tissue dynamics, which describes stress distribution flow field on large scales. In absence apoptosis, we consider behave as an elastic solid. Cell apoptosis introduce sources that, in general, are anisotropic. By combining number balance with...
Through the analysis of a simple two-level model, we show how and to what extent structures possessing vectorial symmetry act as pumps in presence dissipation. The relevance new separation concepts protein motor assemblies is discussed.
We introduce the concept of self-tuned criticality as a general mechanism for signal detection in sensory systems. In case hearing, we argue that active amplification faint sounds is provided by dynamical system maintained at threshold an oscillatory instability. This can account exquisite sensitivity auditory and its wide dynamic range well capacity to respond selectively different frequencies. A specific model sound hair cells inner ear discussed. show collection motor proteins within...
Sorting of lipids and proteins is a key process allowing eukaryotic cells to execute efficient accurate intracellular transport maintain membrane homeostasis. It occurs during the formation highly curved intermediates that shuttle between cell compartments. Protein sorting reasonably well described, but lipid much less understood. Lipid has been proposed be mediated by physical mechanism based on coupling composition high curvature intermediates. To test this hypothesis, we have performed...
Cells are populated by a vast array of membrane-binding proteins that execute critical functions. Functions, like signaling and intracellular transport, require the abilities to bind highly curved membranes trigger membrane deformation. Among these is amphiphysin 1, implicated in clathrin-mediated endocytosis. It contains Bin-Amphiphysin-Rvs domain with an N-terminal amphipathic helix senses generates curvature. However, understanding parameters distinguishing two functions missing. By...
Morphogenesis during embryo development requires the coordination of mechanical forces to generate macroscopic shapes organs. We propose a minimal theoretical model, based on cell adhesion and actomyosin contractility, which describes various epithelial cells bending buckling sheets, as well relative stability cellular tubes spheres. show that, understand these processes, full 3D description is needed, but that simple scaling laws can still be derived. The morphologies observed in vivo...
Abstract The surrounding microenvironment limits tumour expansion, imposing a compressive stress on the tumour, but little is known how pressure propagates inside tumour. Here we present non-destructive cell-like microsensors to locally quantify mechanical distribution in three-dimensional tissue. Our sensors are polyacrylamide microbeads of well-defined elasticity, size and surface coating enable internalization within cellular environment. By isotropically compressing multicellular...
Membrane scission is essential for intracellular trafficking. While BAR domain proteins such as endophilin have been reported in dynamin-independent of tubular membrane necks, the cutting mechanism has yet to be deciphered. Here, we combine a theoretical model, vitro, and vivo experiments revealing how protein scaffolds may cut membranes. We demonstrate that scaffold bound underlying tube creates frictional barrier lipid diffusion; elongation thus builds local tension until undergoes through...
We study theoretically the effects of confinement on active polar gels such as actin network eukaryotic cells. Using generalized hydrodynamics equations derived for gels, we predict, in case quasi one-dimensional geometry, a spontaneous flow transition from homogeneously polarized immobile state small thicknesses, to perturbed flowing larger thicknesses. The is not driven by an external field but activity system. suggest several possible experimental realizations.
We present a simple stochastical model for motor molecules that cooperate in large groups. This could apply actin-myosin motors muscles and motility assays with high concentration of molecules. calculate the dependence velocity on applied force as function ATP show existence dynamical phase transition allowing spontaneous directed motion even if system is spatially symmetric. In symmetric case, problem isomorphous to paramagnet-ferromagnet transition, asymmetric case liquid-vapor transition.
The elucidation of physical and molecular mechanisms by which a membrane tube is generated from reservoir central to the understanding structure dynamics intracellular organelles transport intermediates in eukaryotic cells. Compelling evidence exists that motors dynein kinesin families are involved tubulation organelles. Here, we show lipid giant unilamellar vesicles (GUVs), molecules have been attached means small polystyrene beads, give rise tubes complex tubular networks when incubated...
In eukaryotic cells, nanotubes represent a substantial fraction of transport intermediates between organelles. They are extracted from membranes by molecular motors walking along microtubules. We previously showed that kinesins fixed on giant unilamellar vesicles in contact with microtubules sufficient to form vitro . Motors were attached the membrane through beads, thus facilitating cooperative effects. Koster et al. [Koster, G., VanDuijn, M., Hofs, B. & Dogterom, M. (2003) Proc. Natl....
We study the energetics of isothermal ratchets which are driven by a chemical reaction between two states, and operate in contact with single heat bath constant temperature. discuss generic aspects energy transduction such as Onsager relations linear response regime well efficiency dissipation close to far from equilibrium. In where system operates reversibly, is general nonzero. Studying properties for specific examples landscapes transitions, we observe that can have maximum function Far...