Marc Leonetti

Themes

Disciplines:

• Soft matter

• fluid mechanics at low Reynolds number

• nonlinear physics

• biophysics/biomechanics

• elasticity

Research issues:

• physics of interfaces, membranes and shells: from structure to physical and mechanical properties

• encapsulation

• spatiotemporal dynamics of soft particles and their shapes, from particle scale to suspension

• Blood: margination, shape of RBC

• electric activity of cells

Methodologies:

experiment, numerics and theory

Techniques:

• optical microcopy (phase, DIC, fluorescence, RICM), microfluidics, high-speed imaging, surface rheometer
• FEM-BEM code to study the shape and the  dynamics of surfactant-laden  droplets, vesicles, polymersomes and capsules

Recherche

_{Shape and dynamics  of vesicles under flow  (theory/simulations)}

Collaboration: P.G. Chen, M. Jaeger, M2P2, Marseille, A. Farutin, c. Misbah, LIPhy, Grenoble

Past collaboration: G. Boëdec  (IRPHE, AMU, S. Gekle (University  of Bayreuth)

A vesicle is a droplet bounded by a lipid bilayer embedded in another liquid. This system knows a long standing interest due to its ability to mimic some properties of red blood cells. But it is also a fascinating system at a theoretical point of view, thanks to its original interfacial properties: resistance to bending and local surface incompressibility.  It is one of the ways to understand how soft matter flows. We study the shape and the spatiotemporal dynamics of vesicles in flow or in electric field by a methodology associating theory and numerical simulations.  We have developed our own code based on Finite Element Method and Boundary Element Method. The instabilities are characterized in the framework of nonlinear physics and soft matter. The results can highlight some behaviors of red blood cells in microcirculation.

_{Margination (experiments)}

Past  collaboration: A. Aouane, J. Harting (Juëlich), C. Wagner (Universitaet des Saarlandes)

In microcirculation, Red Blood Cells (RBC) flow in the main part of vessels around the centre line while White Blood Cells (WBC) and Platelets (Pt) are more gathered at the edge. This phenomenon called margination is an essential step of diapedesis as WBCs and Pts are now much closer to their zones of importance in the cases of injury or tumor for example.

Margination is not observed without flow highlighting the role of hydrodynamic interactions between cells and vessel’s wall (glycocalyx and endothelial cells). Several models have been proposed involving either viscoelasticity of plasma or aggregation of globules or differentiated hydrodynamic interactions depending on a mismatch of properties (size, stiffness, shape) between WBCs and RBCs for example. Our project is to decipher the physical mechanisms in physiological conditions at the scale of vessels and networks.

Recently, in the framework of the PhD of Revaz Chachanidze, we have shown experimentally that a difference of rigidity between healthy and rigidified RBCs leads to margination, i.e. a segregation under flow: collaboration with C. Wagner, Universitaet des Saarlandes, Germany.

Fluid interfaces (experiments/theory/numerics)

Doctorant : P. Regazzi

Collaboration: E. Rio et A. Salonen, LPS, Orsay, H. Klein du département SSP, CINaM, P.G. Chen, M. Jaeger (M2P2, AMU)

Funding: ANR

This project concerns the interfaces between two miscible fluids and the surfactants-laden interfaces. We plan to develop new tools to characterize their mechanical response to constraints. We will also study some configurations at the scale of one or several droplets which depend on the local behavior of interfaces.

Lien : SSP_InterfacesFluides

Encapsulation (experiments/theory/numerics)

Past  collaboration: D. Barthès-Biesel  (BMBI, UTC), J. Deschamps (IRPHE, AMU), C. de Loubens (LRP, Grenoble), F. Edwards-Lévy (ICMR, Reims University), Reims) M. Georgelin (IRPHE, AMU), A.-V. Salsac (BMBI, UTC)

Encapsulation is a simple way of protecting, transporting and delivering internalized principles, but also of structuring space. This concerns very diverse fields such as food, cosmetics, new materials for construction or medicine. The capsules studied are droplets bounded by a thin polymer film (shell also called membrane or skin) and immersed in a liquid. The structural and mechanical properties of such objects are still poorly known: behaviour laws, elastic and viscous moduli, rupture, dynamics, etc. Indeed, there are few experimental results. A multi-scale analysis would permit to gain insight in the physics of these smart soft particles.

A - Thin films of polymers

Polymer layers can be made of various manners. We focus on interfacial polymerization where the chemical reaction between reactants is accurately localized in space, at the oil/water interface for example. When the interface is flat, we will investigate polymerization by surface rheometry, AFM and light  diffusion to determine the multi-scale structure during the growth of the membrane and its mechanical properties. It means the elastic and viscous components of the response to external constraints.

Lien : SSP_InterfacesFluides

B - dynamics, shape, wrinkling and rupture of an elastic capsule

Doctorant: P. Regazzi

Funding: CNES

The behavior of capsules (closed elastic system) under flow is governed by the coupling at the interface between the viscous stress jump and the elastic response of the shell. In the linear regime, all the elastic models are  similar to the Hooke model. However, some capsules can sustain more than 100 % of elongation  without plasticity leading to the question of the constitutive law  (stress-strain relation) governing the material shell deformation. In the same context, we are  also interested in the rupture of capsules as a function of the cohesion of its membrane which  depends on the cohesive properties of the membrane. Beyond, a capsule can exhibit two kinds of shape instabilities under flow. On one hand, the fluid-structure interactions (mechanical equilibrium) can lead to compressive domains and then to the potential emergence of wrinkles, a shape modulation with a small wavelength compared to the capsule's size. Our aim is to decipher the physical mechanisms in the regimes near threshold and far from threshold. Beyond, we expect secondary instabilities and competition between the different branches of solutions. On the  other hand, in contrast  with experimental results, there are numerous numerical studies in literature. They have shown that capsules also experience a zoology of dynamics (oscillations for example) where the shape is modulated at the capsule's scale. We will study experimentally how the shape of a capsule evolves.

See SSP_Capsules for other works on capsules in CINaM

C – Interactions between capsules, collective behaviors

The strong deformation of capsules in flow induces more complex hydrodynamic interactions than between rigid particles. To this, it is necessary to add colloidal interactions as well as friction, key ingredients for the understanding of the rheology of rigid particle suspensions. We propose to study the implication of all these contributions to the case of binary interactions and more broadly in suspension.

Parcours

_Other:

·       _{Previous fundings : ANR, ACI, Labex, CNES}

·       _{Membre du Conseil Scientifique de l'Institut de Physique du CNRS (2024-...)}

·       _{Treasurer of the Société Française de Physique(2017-...)}

·       _{Trésorier de la DMC (2012-2017)}

_{.   CNU section 28}

·       _{Prize Young Researcher D. Guinier, French  Society of Physics}

·       _{DEA de Physique des Liquides (master degree)}

·       _{ENS Paris}

_{Publications:}

[63] J. Lyu, P.G. Chen, A. Farutin, M. Jaeger, C. Misbah and M. Leonetti, Swirling of vesicles, shapes and dynamics in Poiseuille flow  as a model of RBC microcirculation, Phys. Rev. Fluids 8 (2023) L021602

[62] Breakups of Chitosan Microcapsules in Extensional Flow, Journal of Colloid and Interface Science 629 (2023) 445-454

[61] K. Xie and M. Leonetti, Mechanical characterization of core-shell microcapsules, CRAS to appear 2023

[60] Structural characterization of the interfacial self- assembly of chitosan with oppositely charged surfactant, Journal of Colloid and Interface Science 616 (2022) 911 920

[59] J. Lyu, K. Xie, R. Chachanidze, A. Kahli, G. Boedec and M. Leonetti, Dynamics of shape instability of a polymersome tether, Physics of Fluids 33 (2021) 122016

[58] S. Das, M. Jaeger, M. Leonetti, R. Thaokar and G. Chen, Effect of pulse width on the dynamics of a deflated vesicle in unipolar and bipolar pulsed electric fields, Physics of Fluids, 33 (2021) 081905

[57] H. Saidani, M. Leonetti, H. Kmita and F. Homblé, The open state selectivity of the bean seed VDAC depends on stigmasterol and ion concentration, International Journal of Molecular Sciences 22, 3024 (2021)

[56] G. Simionato, K. Hinkelman, R. Chachanidze, M. Leonetti, L. Kastner, C. Wagner and S. Quint, Red blood cell phenotyping from 3D confocal images using artificial neural networks, PLOS Computational biology 17 (2021) e1008934

[55] M. Maleki, C. de Loubens, K. Xie, E. Talansier, H. Bodiguel et M. Leonetti, Membrane emulsification for high throughput produc- tion of uniform microcapsules with tunable mechanical properties, Chem. Eng. Sci 237, 116567 (2021)

[54] J. Lyu, P. G. Chen, G. Boedec, M. Leonetti and M. Jaeger, An isogeometric boundary element method for soft particles flowing in microfluidic channels, Computers and Fluids 214 (2021) 104786

[53] P. G. Chen, J. Lyu, M. Jaeger and M. Leonetti, Shape transition and hydrodynamics of vesicles in tube flow, Phys. Rev. Fluids 5 (2020) 043602

[52] M. Degonville, G. Boedec and M. Leonetti, Oblate to prolate tran- sition of a vesicle in shear flow, EPJE 42, 116 (2019)

[51] A. Naillon, C. de Loubens, W. Chevremont, S. Rouze, M. Leo- netti and H. Bodiguel, Dynamics of particle migration in confined viscoelastic Poiseuille flows, Phys. Rev. Fluids 4 (2019) 053301

[50] A. Abay, G. Simionato, R. Chachanidze, A. Bogdanova, P. Bianchi, E. Akker, M. Lindern, M. Leonetti, G. Minetti, C. Wagner and L. Kaestner, Glutaraldehyde - a subtle tool in the investigation of healthy and pathologic red blood cells, Frontiers in Physiology, ID 450377 (2019)

[49] J. Lyu, P. G. Chen, G. Boedec, M. Leonetti and M. Jaeger, Hybrid continuous-coarse graining modeling of erythrocytes, CRAS mécanique, 346, pp 439-448 (2018)

[48] K. Xie, C. de Loubens, M. Jaeger, D. Gunes and M. Leonetti, Tunable interfacial rheological properties of soft mono-disperse po- lyelectrolytes microcapsules, Soft Matter, 36, pp 6208-6217 (2017)

[47] L. Mlayeh, E-V. Krammer, M. Leonetti, M. Prévost and F. Hom- blé, The mitochondrial VDAC recruits phasphatidylethanolamine lipids for its proper functioning, BBA-Bioenergetics 1858, pp 786- 794 (2017)

[46] J. Gubspun, C. de Loubens, R. Trozzo, M. Jaeger, M. Georgelin, J. Deschamps and M. Leonetti, Flow induced by a microcapsule in a cylindrical capillary, Fluid Dyn. Research 49, 035501 (2017)

[45] G. Martrou, M. Leonetti, D. Gigmes and T. Trimaille, Straight- forward preparation of surface modified electrospun microfibers as suitable supports for protein immobilization, Polym. Chem. 8, 1790 (2017) (IF = 5.687)

[44] G. Boedec, M. Leonetti and M. Jaeger, Isogeometric FEM-BEM simulations of capsules and vesicles dynamics in Stokes flow, J. Comp. Phys. 342, 117-138 (2017)

[43] F. Homblé, H. Kmita, H. Saidani and M. Leonetti, Plant VDAC permeability: molecular basis and role in oxidative stress, in Molecular Basis for Mitochondrial Signaling edited by Tatiana Rostovtseva, Springer Biological and Medical Physics, Biomedical Engineering (2017)

[42] H. Saidani, E-V. Krammer, M. Leonetti, D. Grobys, H. Kmita, M. Prevost and F. Homble, Towards understanding of plant mitochon- drial VDAC proteins: an overview of common bean (Phaseolus) VDAC proteins, AIMS Biophysics 4, 43-62 (2017)

[41] J. Gounley, G. Boedec, M. Jaeger and M. Leonetti, Influence of surface viscosity on droplets in shear flow, J. Fluid Mech. 791, 464-494 (2016).

[40] C. de Loubens, J. Deschamps, F. Edwards-Lévy et M. leonetti, Tanktreading of microcapsules in shear flow, J. Fluid Mech. 789, 750-767 (2016).

[39] A. Guckenberger, M. Schraml, P. G. Chen, M. Leonetti and S. Gekle, On the bending algorithms for soft objects in flows, Com- puter Physics Communications 207, 1-23 (2016)

[38] J. Gubspun, P-Y. Gires, C. de Loubens, D. Barthes-Biesel, J. Des- champs, M. Georgelin, M. Leonetti, E. Leclerc, F. Edwards-Lévy and A-V. Salsac, Characterization of the mechanical properties of cross-linked serum albumin microcapsules: effect of size and pro- tein concentration, Colloid Polym. Sci. 294, 1381- 1389 (2016).

[37] M. Dionzou, A. Mozere, C. Roux, B. Lonetti, J.-D. Marty, C. Min- gotaud, P. Joseph, D. Goudouneche, B. Payre, M. Leonetti and A.-F. Mingotaud, Comparison of methods for the fabrication and the characterization of polymer self-assemblies : what are the im- portant parameters ?, Soft Matter 12, 2166-2176 (2016).

[36] C. de Loubens, J. Deschamps, G. Boedec and M. Leonetti, Stret- ching of capsules in an elongation flow, a route to constitutive law, J. Fluid Mech. 767, R3 (2015).

[35] R. Trozzo, G. Boedec, M. Leonetti and M. Jaeger, Axisymmetric Boundary Element Method for vesicles in a capillary, J. Comp. Phys. 289, 62-82 (2015)

[34] C. deLoubens, J.Deschamps, M.Georgelin, A.Charrier, F.Edwards-Lévy and M. Leonetti, Mechanical characterization of cross-linked serum albumin microcapsules, Soft Matter 10, 4561-4568 (2014)

[33] G. Boedec, M. Jaeger and M. Leonetti, Pearling instability of a cylindrical vesicle, J. Fluid Mech. 743, 262-279 (2014)

............................