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Publications (en anglais)

  1. Articles scientifiques
  2. Livres
  3. Mémoires

 

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1. Articles scientifiques

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    Conformational Space of the Translocation Domain of Botulinum Toxin: Atomistic Modeling and Mesoscopic Description of the Coiled-Coil Helix Bundle

    Alexandre Delort, Grazia Cottone, Thérèse E. Malliavin, Martin Michael Müller

    Résumé     

    Int. J. Mol. Sci., 25: 2481, 2024.

     


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    Flexoelectric fluid membrane vesicles in spherical confinement

    Niloufar Abtahi, Lila Bouzar, Nadia Saidi-Amroun, Martin Michael Müller

    Résumé     Plus d'infos

    EPL, 131(1): 18001, 2020. Cf. aussi arXiv:2006.04475.

     


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    Isometric bending requires local constraints on free edges

    Jemal Guven, Martin Michael Müller, Pablo Vázquez-Montejo

    While the shape equations describing the equilibrium of an unstretchable thin sheet that is free to bend are known, the boundary conditions that supplement these equations on free edges have remained elusive. Intuitively, unstretchability is captured by a constraint on the metric within the bulk. Naïvely one would then guess that this constraint is enough to ensure that the deformations determining the boundary conditions on these edges respect the isometry constraint. If matters were this simple, unfortunately, it would imply unbalanced torques (as well as forces) along the edge unless manifestly unphysical constraints are met by the boundary geometry. In this article, we identify the source of the problem: not only the local arc-length but also the geodesic curvature need to be constrained explicitly on all free edges. We derive the boundary conditions which follow. In contrast to conventional wisdom, there is no need to introduce boundary layers. This framework is applied to isolated conical defects, both with deficit as well, but more briefly, as surplus angles. Using these boundary conditions, we show that the lateral tension within a circular cone of fixed radius is equal but opposite to the radial compression, and independent of the deficit angle itself. We proceed to examine the effect of an oblique outer edge on this cone perturbatively demonstrating that both the correction to the geometry as well as the stress distribution in the cone kicks in at second order in the eccentricity of the edge.

     Fermer     Plus d'infos

    Math. Mech. Solids, 24: 4051, 2019. Cf. aussi arXiv:1904.05855.

     


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    Helical Superstructure of Intermediate Filaments

    Lila Bouzar, Martin Michael Müller, René Messina, Bernd Nöding, Sarah Köster, Hervé Mohrbach, Igor M. Kulić

    Résumé     Plus d'infos

    Phys. Rev. Lett., 122: 098101, 2019. Cf. aussi arXiv:1803.04691.

     


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    Vesicle dynamics in confined steady and harmonically modulated Poiseuille flows

    Zakaria Boujja, Chaouqi Misbah, Hamid Ez-Zahraouy, Abdelilah Benyoussef, Thomas John, Christian Wagner, Martin Michael Müller

    We present a numerical study of the time-dependent motion of a membrane vesicle in a channel under an imposed flow. In a Poiseuille flow the shape of the vesicle depends on the flow strength, the mechanical properties of the membrane, and the width of the channel. In a wide parameter region, the emerging snaking shape shows an oscillatory motion like a swimmer flagella even though the flow is stationary. We quantify this behavior by the amplitude and frequency of the oscillations of the vesicle's center of mass. The influence of an amplitude modulation of the imposed flow on the dynamics and shape of the snaking vesicle is also investigated. We find that this modulation---when sufficiently small---induces a modulation in amplitude and frequency of the center of mass of the snaking vesicle. For large modulation amplitudes transitions to static shapes are observed.

     Fermer     

    Phys. Rev. E, 98: 043111, 2018. Cf. aussi arXiv:1810.04500.

     


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    Confining a fluid membrane vesicle of toroidal topology in an adhesive hard sphere

    Lila Bouzar, Ferhat Menas, Martin Michael Müller

    Résumé     Plus d'infos

    IOP Conf. Series: MSE, 186: 012021, 2017.

     


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    Squeezed helical elastica

    Lila Bouzar, Martin Michael Müller, Pierre Gosselin, Igor M. Kulić, Hervé Mohrbach

    Résumé     Plus d'infos

    Eur. Phys. J. E, 39: 114, 2016. Cf. aussi arXiv:1606.03611.

     


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    How bio-filaments twist membranes

    Julien Fierling, Albert Johner, Igor M. Kulić, Hervé Mohrbach, Martin Michael Müller

    Résumé     

    Soft Matter, 12: 5747, 2016.

     


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    Toroidal membrane vesicles in spherical confinement

    Lila Bouzar, Ferhat Menas, Martin Michael Müller

    Résumé     Plus d'infos

    Phys. Rev. E, 92: 032721, 2015. Cf. aussi arXiv:1509.00765.

     


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    Non-linear buckling and symmetry breaking of a soft elastic sheet sliding on a cylindrical substrate

    Norbert Stoop, Martin Michael Müller

    We consider the axial compression of a thin sheet wrapped around a rigid cylindrical substrate. In contrast to the wrinkling-to-fold transitions exhibited in similar systems, we find that the sheet always buckles into a single symmetric fold, while periodic solutions are unstable. Upon further compression, the solution breaks symmetry and stabilizes into a recumbent fold. Using linear analysis and numerics, we theoretically predict the buckling force and energy as a function of the compressive displacement. We compare our theory to experiments employing cylindrical neoprene sheets and find remarkably good agreement.

     Fermer     Plus d'infos

    Int. J. Non-Linear Mech., 75: 115, 2015. Cf. aussi arXiv:1503.05030.

     


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    Crunching Biofilament Rings

    Julien Fierling, Martin Michael Müller, Hervé Mohrbach, Albert Johner, Igor M. Kulić

    We discuss a curious example for the collective mechanical behavior of coupled non-linear monomer units entrapped in a circular filament. Within a simple model we elucidate how multistability of monomer units and exponentially large degeneracy of the filament's ground state emerge as a collective feature of the closed filament. Surprisingly, increasing the monomer frustration, i.e., the bending prestrain within the circular filament, leads to a conformational softening of the system. The phenomenon, that we term polymorphic crunching, is discussed and applied to a possible scenario for membrane tube deformation by switchable dynamin or FtsZ filaments. We find an important role of cooperative inter-unit interaction for efficient ring induced membrane fission.

     Fermer     Plus d'infos

    Europhys. Lett., 107(6): 68002, 2014. Cf. aussi arXiv:1408.6787.

     


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    Confotronic dynamics of tubular filaments

    Osman Kahraman, Hervé Mohrbach, Martin Michael Müller, Igor M. Kulić

    Résumé     Plus d'infos

    Soft Matter, 10(16): pp. 2836-2847, 2014. Cf. aussi arXiv:1312.3106.

     


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    Whirling skirts and rotating cones

    Jemal Guven, J. A. Hanna, Martin Michael Müller

    Résumé     

    New J. Phys., 15: 113055, 2013. Cf. aussi arXiv:1306.2619.

     


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    Myotubularin and PtdIns3P remodel the sarcoplasmic reticulum in muscle in vivo

    Leonela Amoasii, Karim Hnia, Gaëtan Chicanne, Andreas Brech, Belinda Simone Cowling, Martin Michael Müller, Yannick Schwab, Pascale Koebel, Arnaud Ferry, Bernard Payrastre, Jocelyn Laporte

    The sarcoplasmic reticulum (SR) is a specialized form of endoplasmic reticulum (ER) in skeletal muscle and is essential for calcium homeostasis. The mechanisms involved in SR remodeling and maintenance of SR subdomains are elusive. In this study, we identified myotubularin (MTM1), a phosphatase mutated in X-linked centronuclear myopathy (XLCNM), as a key regulator of phosphoinositide-3-monophosphate (PtdIns3P) levels at the SR. Mtm1 deficient mouse muscles and myoblasts from XLCNM patients exhibit abnormal SR/ER networks. In vivo modulation of MTM1 enzymatic activity in muscle using ectopic expression of wild-type or a dead-phosphatase MTM1 protein leads to differential SR remodeling. Active MTM1 is associated to flat membrane stacks, while dead-phosphatase MTM1 mutant promotes highly curved cubic membranes originating from the SR and enriched in PtdIns3P. Moreover, expression of the PtdIns3P binding module 2XFYVE also modified the SR shape at triads. Our findings, supported by the parallel analysis of the Mtm1- null mouse and in vivo study, reveal a direct function of MTM1 enzymatic activity in SR remodeling and a key role for its substrate PtdIns3P in promoting SR membrane curvature in skeletal muscle. We propose that alteration in SR remodeling is a primary cause of X-linked centronuclear myopathy. The tight regulation of PtdIns3P on specific membrane subdomains may be a general mechanism to control membrane curvature.

     Fermer     

    J. Cell Sci., 126(8): 1806, 2013.

     


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    Dipoles in thin sheets

    Jemal Guven, J. A. Hanna, Osman Kahraman, Martin Michael Müller

    Résumé     Plus d'infos

    Eur. Phys. J. E, 36: 106, 2013. Cf. aussi arXiv:1212.3262.

     


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    Fluid membrane vesicles in confinement

    Osman Kahraman, Norbert Stoop, Martin Michael Müller

    Résumé     Plus d'infos

    New J. Phys., 14: 095021, 2012.

     


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    Petal shapes of sympetaleous flowers: the interplay between growth, geometry and elasticity

    Martine Ben Amar, Martin Michael Müller, Miguel Trejo

    Résumé     Plus d'infos

    New J. Phys., 14: 085014, 2012. Choisi pour les Highlights of 2012.

     


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    Morphogenesis of membrane invaginations in spherical confinement

    Osman Kahraman, Norbert Stoop, Martin Michael Müller

    We study the morphology of a fluid membrane in spherical confinement. When the area of the membrane is slightly larger than the area of the outer container, a single axisymmetric invagination is observed. For higher area, self-contact occurs: the invagination breaks symmetry and deforms into an ellipsoid-like shape connected to its outer part via a small slit. For even higher areas, a second invagination forms inside the original invagination. The folding patterns observed could constitute basic building blocks in the morphogenesis of biological tissues and organelles.

     Fermer     Plus d'infos

    Europhys. Lett., 97(6): 68008, 2012. Cf. aussi arXiv:1201.2518.

     


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    Conical instabilities on paper

    Jemal Guven, Martin Michael Müller, Pablo Vázquez-Montejo

    The stability of the fundamental defects of an unstretchable flat sheet is examined. This involves expanding the bending energy to second order in deformations about the defect. The modes of deformation occur as eigenstates of a fourth-order linear differential operator. Unstretchability places a global linear constraint on these modes. Conical defects with a surplus angle exhibit an infinite number of states. If this angle is below a critical value, these states possess an n-fold symmetry labeled by an integer, n ≥ 2. A nonlinear stability analysis shows that the 2-fold ground state is stable, whereas excited states possess 2(n - 2) unstable modes which come in even and odd pairs.

     Fermer     Plus d'infos

    J. Phys. A: Math. Theor., 45(1): 015203, 2012. Cf. aussi arXiv:1107.5008.

     


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    Interface-mediated interactions: Entropic forces of curved membranes

    Pierre Gosselin, Hervé Mohrbach, Martin Michael Müller

    Particles embedded in a fluctuating interface experience forces and torques mediated by the deformations and by the thermal fluctuations of the medium. Considering a system of two cylinders bound to a fluid membrane we show that the entropic contribution enhances the curvature-mediated repulsion between the two cylinders. This is contrary to the usual attractive Casimir force in the absence of curvature-mediated interactions. For a large distance between the cylinders, we retrieve the renormalization of the surface tension of a flat membrane due to thermal fluctuations.

     Fermer     Plus d'infos

    Phys. Rev. E, 83(5): 051921, 2011. Cf. aussi arXiv:1011.1221.

     


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    Self-Contact and Instabilities in the Anisotropic Growth of Elastic Membranes

    Norbert Stoop, Falk K. Wittel, Martine Ben Amar, Martin Michael Müller, Hans J. Herrmann

    We investigate the morphology of thin discs and rings growing in circumferential direction. Recent analytical results suggest that this growth produces symmetric excess cones (e-cones). We study the stability of such solutions considering self-contact and bending stress. We show that, contrary to what was assumed in previous analytical solutions, beyond a critical growth factor, no symmetric e-cone solution is energetically minimal any more. Instead, we obtain skewed e-cone solutions having lower energy, characterized by a skewness angle and repetitive spiral winding with increasing growth. These results are generalized to discs with varying thickness and rings with holes of different radii.

     Fermer     Plus d'infos

    Phys. Rev. Lett., 105(6): 068101, 2010. Cf. aussi arXiv:1007.1871.

     


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    Cell Model Approach to Membrane Mediated Protein Interactions

    Martin Michael Müller, Markus Deserno

    Résumé     Plus d'infos

    Prog. Theor. Phys. Suppl., 184: pp. 351-363, 2010.

     


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    Hamiltonian formulation of surfaces with constant Gaussian curvature

    Miguel Trejo, Martine Ben Amar, Martin Michael Müller

    Résumé     Plus d'infos

    J. Phys. A: Math. Theor., 42(42): 425204, 2009.

     


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    Local Membrane Mechanics of Pore-Spanning Bilayers

    Ingo Mey, Milena Stephan, Eva K. Schmitt, Martin Michael Müller, Martine Ben Amar, Claudia Steinem, Andreas Janshoff

    Résumé     Plus d'infos

    J. Am. Chem. Soc., 131(20): pp. 7031-7039, 2009.

     


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    Elasticity Mapping of Pore-Suspending Native Cell Membranes

    Bärbel Lorenz, Ingo Mey, Siegfried Steltenkamp, Tamir Fine, Christina Rommel, Martin Michael Müller, Alexander Maiwald, Joachim Wegener, Claudia Steinem, Andreas Janshoff

    Résumé     Plus d'infos

    Small, 5(7): pp. 832-838, 2009.

     


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    Conical Defects in Growing Sheets

    Martin Michael Müller, Martine Ben Amar, Jemal Guven

    Résumé     Plus d'infos

    Phys. Rev. Lett., 101(15): 156104, 2008. Cf. aussi arXiv:0807.1814.

     


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    How paper folds: bending with local constraints

    Jemal Guven, Martin Michael Müller

    Résumé     Plus d'infos

    J. Phys. A: Math. Theor., 41(5): 055203, 2008. Cf. aussi arXiv:0712.0978.

     


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    Contact lines for fluid surface adhesion

    Markus Deserno, Martin Michael Müller, Jemal Guven

    When a fluid surface adheres to a substrate, the location of the contact line adjusts in order to minimize the overall energy. This adhesion balance implies boundary conditions which depend on the characteristic surface deformation energies. We develop a general geometrical framework within which these conditions can be systematically derived. We treat both adhesion to a rigid substrate as well as adhesion between two fluid surfaces, and illustrate our general results for several important Hamiltonians involving both curvature and curvature gradients. Some of these have previously been studied using very different techniques, others are to our knowledge new. What becomes clear in our approach is that, except for capillary phenomena, these boundary conditions are not the manifestation of a local force balance, even if the concept of surface stress is properly generalized. Hamiltonians containing higher order surface derivatives are not just sensitive to boundary translations but also notice changes in slope or even curvature. Both the necessity and the functional form of the corresponding additional contributions follow readily from our treatment.

     Fermer     Plus d'infos

    Phys. Rev. E, 76(1): 011605, 2007. Cf. aussi cond-mat/0703019.
    Choisi pour le Virtual Journal of Biological Physics Research.

     


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    Balancing torques in membrane-mediated interactions: Exact results and numerical illustrations

    Martin Michael Müller, Markus Deserno, Jemal Guven

    Résumé     Plus d'infos

    Phys. Rev. E, 76(1): 011921, 2007. Cf. aussi cond-mat/0702340.
    Choisi pour le Virtual Journal of Biological Physics Research.

     


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    Aggregation and vesiculation of membrane proteins by curvature-mediated interactions

    Benedict J. Reynwar, Gregoria Illya, Vagelis A. Harmandaris, Martin Michael Müller, Kurt Kremer, Markus Deserno

    Résumé     Plus d'infos

    Nature 447(7143): pp. 461-464, 2007.

     


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    How to determine local elastic properties of lipid bilayer membranes from atomic-force-microscope measurements: A theoretical analysis

    Davood Norouzi, Martin Michael Müller, Markus Deserno

    Résumé     Plus d'infos

    Phys. Rev. E, 74(6): 061914, 2006. Cf. aussi cond-mat/0602662.
    Choisi pour le Virtual Journal of Biological Physics Research.

     


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    Mechanical Properties of Pore-Spanning Lipid Bilayers Probed by Atomic Force Microscopy

    Siegfried Steltenkamp, Martin Michael Müller, Markus Deserno, Christian Hennesthal, Claudia Steinem, Andreas Janshoff

    Résumé     Plus d'infos

    Biophys. J., 91(1): pp. 217-226, 2006.

     


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    Interface mediated interactions between particles -- a geometrical approach

    Martin Michael Müller, Markus Deserno, Jemal Guven

    Résumé     Plus d'infos

    Phys. Rev. E, 72(6): 061407, 2005. Cf. aussi cond-mat/0506019.
    Choisi pour le Virtual Journal of Biological Physics Research.

     


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    Geometry of surface-mediated interactions

    Martin Michael Müller, Markus Deserno, Jemal Guven

    Soft interfaces can mediate interactions between particles bound to them. The force transmitted through the surface geometry on a particle may be expressed as a closed line integral of the surface stress tensor around that particle. This contour may be deformed to exploit the symmetries present; for two identical particles, one obtains an exact expression for the force between them in terms of the local surface geometry of their mid-plane; in the case of a fluid membrane the sign of the interaction is often evident. The approach, by construction, is adapted directly to the surface and is independent of its parameterization. Furthermore, it is applicable for arbitrarily large deformations; in particular, it remains valid beyond the linear small-gradient regime.

     Fermer     Plus d'infos

    Europhys. Lett., 69(3): pp. 482-488, 2005. Cf. aussi cond-mat/0409043.

     


 

 

2. Livres

 

  • New Trends in the Physics and Mechanics of Biological Systems
    Lecture Notes of the Les Houches Summer School, vol. 92 (Oxford University Press, 2011),
    éd. par Martine Ben Amar, Alain Goriely, Martin Michael Müller et Leticia Cugliandolo.

    Chapitre 9 :
    The physics of the cell membrane
    Martin Michael Müller et Martine Ben Amar.

 

 


 

 

3. Mémoires

  • Theoretical examinations of interface mediated interactions between colloidal particles, mémoire (2004).
  •  

  • Theoretical studies of fluid membrane mechanics, thèse de doctorat (2007).


  • Symmetry breaking in bioelasticity, thèse d'habilitation à diriger des recherches (2015).

 

 

 
     

 

     © Martin Michael Müller