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1. Articles scientifiques
 Flexoelectric fluid membrane vesicles in spherical confinement
Niloufar Abtahi, Lila Bouzar, Nadia SaidiAmroun, Martin Michael Müller 
Résumé
Plus d'infos
EPL, 131(1): 18001, 2020. Cf. aussi arXiv:2006.04475.
 Isometric bending requires local constraints on free edges
Jemal Guven, Martin Michael Müller, Pablo VázquezMontejo 
Résumé
Plus d'infos
Math. Mech. Solids, 24: 4051, 2019. Cf. aussi arXiv:1904.05855.
 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.
 Vesicle dynamics in confined steady and harmonically modulated Poiseuille flows
Zakaria Boujja, Chaouqi Misbah, Hamid EzZahraouy, Abdelilah Benyoussef, Thomas John, Christian Wagner, Martin Michael Müller 
Résumé
Phys. Rev. E, 98: 043111, 2018. Cf. aussi arXiv:1810.04500.
 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.
 Squeezed helical elastica
Lila Bouzar, Martin Michael Müller, Pierre Gosselin, Igor M. Kulić, Hervé Mohrbach 
We theoretically study the conformations of a helical semiflexible filament
confined to a twodimensional surface. This squeezed helix exhibits a variety of unexpected shapes
resembling circles, waves or spirals depending on the material parameters. We explore the conformation
space in detail and show that the shapes can be understood as the mutual elastic interaction of
conformational quasiparticles. Our theoretical results are potentially useful to
determine the material parameters of such helical filaments in an experimental setting.
Fermer
Plus d'infos
Eur. Phys. J. E, 39: 114, 2016. Cf. aussi arXiv:1606.03611.
 How biofilaments twist membranes
Julien Fierling, Albert Johner, Igor M. Kulić, Hervé Mohrbach, Martin Michael Müller 
Résumé
Soft Matter, 12: 5747, 2016.
 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.
 Nonlinear buckling and symmetry breaking of a soft elastic sheet sliding on a cylindrical substrate
Norbert Stoop, Martin Michael Müller 
Résumé
Plus d'infos
Int. J. NonLinear Mech., 75: 115, 2015. Cf. aussi arXiv:1503.05030.
 Crunching Biofilament Rings
Julien Fierling, Martin Michael Müller, Hervé Mohrbach, Albert Johner, Igor M. Kulić 
Résumé
Plus d'infos
Europhys. Lett., 107(6): 68002, 2014. Cf. aussi arXiv:1408.6787.
 Confotronic dynamics of tubular filaments
Osman Kahraman, Hervé Mohrbach, Martin Michael Müller, Igor M. Kulić 
Tubular lattices are ubiquitous in nature and technology. Microtubules and nanotubes of all
kinds act as important pillars of biological cells and the manmade nanoworld. We show that
when prestress is introduced in such structures, localized conformational quasiparticles emerge and
govern the collective shape dynamics of the lattice. When coupled via cooperative interactions these
quasiparticles form largerscale quasipolymer superstructures exhibiting collective dynamic modes
and giving rise to a hallmark behavior radically different from semiflexible beams.
Fermer
Plus d'infos
Soft Matter, 10(16): pp. 28362847, 2014. Cf. aussi arXiv:1312.3106.
 Whirling skirts and rotating cones
Jemal Guven, J. A. Hanna, Martin Michael Müller 
Steady, dihedrally symmetric patterns with sharp peaks may be observed on a spinning skirt, lagging behind the material flow of the fabric. These qualitative features are captured with a minimal model of traveling waves on an inextensible, flexible, generalizedconical sheet rotating about a fixed axis. Conservation laws are used to reduce the dynamics to a quadrature describing a particle in a threeparameter family of potentials. One parameter is associated with the stress in the sheet, aNoether is the current associated with rotational invariance, and the third is a Rossby number which indicates the relative strength of Coriolis forces. Solutions are quantized by enforcing a topology appropriate to a skirt and a particular choice of dihedral symmetry. A perturbative analysis of nearly axisymmetric cones shows that Coriolis effects are essential in establishing skirtlike solutions. Fully nonlinear solutions with threefold symmetry are presented which bear a suggestive resemblance to the observed patterns.
Fermer
New J. Phys., 15: 113055, 2013. Cf. aussi arXiv:1306.2619.
 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 
Résumé
J. Cell Sci., 126(8): 1806, 2013.
 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.
 Fluid membrane vesicles in confinement
Osman Kahraman, Norbert Stoop, Martin Michael Müller 
Résumé
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New J. Phys., 14: 095021, 2012.
 Petal shapes of sympetaleous flowers: the interplay between growth, geometry and elasticity
Martine Ben Amar, Martin Michael Müller, Miguel Trejo 
The growth of a thin elastic sheet imposes constraints on its geometry such as its Gaussian curvature K_{G}.
In this paper, we construct the shapes of sympetalous bellshaped flowers with a constant Gaussian curvature. Minimizing the bending energies
of both the petal and the veins, we are able to predict quantitatively the global shape of these flowers. We discuss two toy problems
where the Gaussian curvature is either negative or positive. In the former case the axisymmetric pseudosphere turns out to mimic the correct
shape before edge curling; in the latter case, singularities of the mathematical surface coincide with strong veins. Using a variational
minimization of the elastic energy, we find that the optimal number for the veins is either four, five or six, a number which is deceptively
close to the statistics on real flowers in nature.
Fermer
Plus d'infos
New J. Phys., 14: 085014, 2012. Choisi pour les Highlights of 2012.
 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, selfcontact occurs: the invagination breaks symmetry
and deforms into an ellipsoidlike 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.
 Conical instabilities on paper
Jemal Guven, Martin Michael Müller, Pablo VázquezMontejo 
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 fourthorder 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 nfold symmetry labeled by an integer, n ≥ 2. A
nonlinear stability analysis shows that the 2fold 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.
 Interfacemediated 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 curvaturemediated repulsion between
the two cylinders. This is contrary to the usual attractive Casimir force in
the absence of curvaturemediated 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.
 SelfContact and Instabilities in the Anisotropic Growth of Elastic Membranes
Norbert Stoop, Falk K. Wittel, Martine Ben Amar, Martin Michael Müller, Hans J. Herrmann 
Résumé
Plus d'infos
Phys. Rev. Lett., 105(6): 068101, 2010. Cf. aussi arXiv:1007.1871.
 Cell Model Approach to Membrane Mediated Protein Interactions
Martin Michael Müller, Markus Deserno 
Membranedeforming proteins can interact through the curvature
fields they create. In the case of many such proteins a cell model
approach can be used to calculate the energy per protein and
predict, whether it would lead to phase segregation or
budformation. Using covariant differential geometry exact results
are derived for the lateral pressure in terms of geometric
properties at the cell boundary. Numerical solutions of the exact
shape equations in the highly nonlinear regime are found and it is
seen that both phase segregation and bud formation can occur.
Fermer
Plus d'infos
Prog. Theor. Phys. Suppl., 184: pp. 351363, 2010.
 Hamiltonian formulation of surfaces with constant Gaussian curvature
Miguel Trejo, Martine Ben Amar, Martin Michael Müller 
Dirac's method for constrained Hamiltonian systems is used to describe surfaces of constant Gaussian curvature. A geometrical free energy, for which these surfaces are equilibrium states, is introduced and interpreted as an action. An equilibrium surface can then be generated by the evolution of a closed space curve.
Since the underlying action depends on second derivatives, the velocity of the curve and its conjugate momentum must be included in the set of phase space variables. Furthermore, the action is linear in the acceleration of the curve and possesses a local symmetryreparametrization invariancewhich implies primary constraints in the canonical formalism. These constraints are incorporated into the Hamiltonian through Lagrange multiplier functions, that are identified as the components of the acceleration of the curve. The formulation leads to four first order partial differential equations, one for each canonical variable.
With the appropriate choice of parametrization only one of these equations has to be solved to obtain the surface which is swept out by the evolving space curve. To illustrate the formalism, several evolutions of pseudospherical surfaces are discussed.
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J. Phys. A: Math. Theor., 42(42): 425204, 2009.
 Local Membrane Mechanics of PoreSpanning Bilayers
Ingo Mey, Milena Stephan, Eva K. Schmitt, Martin Michael Müller, Martine Ben Amar, Claudia Steinem, Andreas Janshoff 
Résumé
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J. Am. Chem. Soc., 131(20): pp. 70317039, 2009.
 Elasticity Mapping of PoreSuspending Native Cell Membranes
Bärbel Lorenz, Ingo Mey, Siegfried Steltenkamp, Tamir Fine, Christina Rommel, Martin Michael Müller, Alexander Maiwald, Joachim Wegener, Claudia Steinem, Andreas Janshoff 
The mechanics of cellular membranes is governed by a nonequilibrium composite framework
consisting of the semiflexible filamentous cytoskeleton and extracellular matrix proteins linked to
the lipid bilayer. While elasticity information of plasma membranes has mainly been obtained from
whole cell analysis, techniques that allow to address local mechanical properties of cell
membranes are desirable to learn how their lipid and protein composition is reflected in the elastic
behavior on local length scales. Here, we introduce an approach based on basolateral
membranes of polar epithelial MadinDarby canine kidney (MDCK) II cells, prepared on a highly ordered porous substrate that
allows elastic mapping on a submicrometer length scale. A strong correlation between the
density of actin filaments and the measured membrane elasticity is found. Spatially resolved indentation experiments carried out with atomic force and fluorescence microscope permit to relate the supramolecular structure to the elasticity of cellular membranes. It is shown that the elastic response of the porespanning cell membranes is governed by the local bending modules rather than the lateral tension.
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Small, 5(7): pp. 832838, 2009.
 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.
 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.
 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.
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Phys. Rev. E, 76(1): 011605, 2007. Cf. aussi condmat/0703019. Choisi pour le Virtual Journal of Biological Physics Research.
 Balancing torques in membranemediated interactions: Exact results and
numerical illustrations
Martin Michael Müller, Markus Deserno, Jemal Guven 
Torques on interfaces can be described by a divergencefree tensor
which is fully encoded in the geometry. This tensor consists of two
terms, one originating in the couple of the stress, the other capturing
an intrinsic contribution due to curvature. In analogy to the description
of forces in terms of a stress tensor, the torque on a particle can be
expressed as a line integral along any contour surrounding the particle.
Interactions between particles mediated by a fluid membrane are studied
within this framework. In particular, torque balance places a strong
constraint on the shape of the membrane. Symmetric twoparticle
configurations admit simple analytical expressions which are valid
in the fully nonlinear regime; in particular, the problem may be
solved exactly in the case of two membranebound parallel cylinders.
This apparently simple system provides some flavor of the remarkably
subtle nonlinear behavior associated with membranemediated interactions.
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Plus d'infos
Phys. Rev. E, 76(1): 011921, 2007. Cf. aussi condmat/0702340. Choisi pour le Virtual Journal of Biological Physics Research.
 Aggregation and vesiculation of membrane proteins by curvaturemediated
interactions
Benedict J. Reynwar, Gregoria Illya, Vagelis A. Harmandaris, Martin Michael Müller, Kurt Kremer, Markus Deserno 
Membrane remodelling plays an important role in cellular tasks such as endocytosis, vesiculation and protein sorting, and in the biogenesis of organelles such as the endoplasmic reticulum or the Golgi apparatus. It is well established that the remodelling process is aided by specialized proteins that can sense as well as create membrane curvature, and trigger tubulation when added to synthetic liposomes. Because the energy needed for such largescale changes in membrane geometry significantly exceeds the binding energy between individual proteins and between protein and membrane, cooperative action is essential. It has recently been suggested that curvaturemediated attractive interactions could aid cooperation and complement the effects of specific binding events on membrane remodelling. But it is difficult to experimentally isolate curvaturemediated interactions from direct attractions between proteins. Moreover, approximate theories predict repulsion between isotropically curving proteins. Here we use coarsegrained membrane simulations to show that curvatureinducing model proteins adsorbed on lipid bilayer membranes can experience attractive interactions that arise purely as a result of membrane curvature. We find that once a minimal local bending is realized, the effect robustly drives protein cluster formation and subsequent transformation into vesicles with radii that correlate with the local curvature imprint. Owing to its universal nature, curvaturemediated attraction can operate even between proteins lacking any specific interactions, such as newly synthesized and still immature membrane proteins in the endoplasmic reticulum.
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Plus d'infos
Nature 447(7143): pp. 461464, 2007.
 How to determine local elastic properties of lipid bilayer membranes
from atomicforcemicroscope measurements: A theoretical analysis
Davood Norouzi, Martin Michael Müller, Markus Deserno 
Résumé
Plus d'infos
Phys. Rev. E, 74(6): 061914, 2006. Cf. aussi condmat/0602662. Choisi pour le Virtual Journal of Biological Physics Research.
 Mechanical Properties of PoreSpanning 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. 217226, 2006.
 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 condmat/0506019. Choisi pour le Virtual Journal of Biological Physics Research.
 Geometry of surfacemediated interactions
Martin Michael Müller, Markus Deserno, Jemal Guven 
Résumé
Plus d'infos
Europhys. Lett., 69(3): pp. 482488, 2005. Cf. aussi condmat/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).
