Missions

By joining a multidisciplinary team, the main objective is to work on creating digital twins that mimic the hydro-chemical-mechanical behaviour of Wharton's jelly (WJ) derivatives ex vivo in the first instance, while participating in the in vivo evaluation of these tools. The main hypothesis is to take into account the couplings between the solid and fluid phases, as well as the chemical components present, in particular electrically charged GAGs which, when combined with collagen, produce an osmotic effect. The fluid-structure interaction will be modelled as a homogenised continuous medium within the framework of poromechanics, while the chemo-mechanical coupling will be generated by the equilibrium of chemical potential through osmosis (Chetoui et al., 2022). Based on preliminary results, it is considered that adjusting cross-links (Lavrand et al., 2024) and GAG content (Scomazzon et al., 2021) on geometrically controlled structures is sufficient to modulate phase interaction phenomena. This will make it possible to distinguish between hydromechanical and chemomechanical couplings. Based on preliminary results, it is considered that adjusting cross-links (Lavrand et al., 2024) and GAG content (Scomazzon et al., 2021) on geometrically controlled structures is sufficient to modulate phase interaction phenomena. This will make it possible to distinguish between hydromechanical and chemomechanical couplings. Finally, the combination of multimodal imaging techniques during ex vivo testing and during monitoring of the animal's response to material integration should provide sufficient data to enable the construction of predictive tools. Currently, experimental data are being collected to evaluate the viscous behaviour of WJ derivatives (Da Rocha et al., 2024), as well as their damage for surgical applications (Da Rocha et al., 2025b).

Activités

Simulations will be developed using finite element analysis (FEA) between LMGC, ICube and LEM3 Labs to model the behaviour of Wharton's jelly samples in an ex vivo and in vivo context.

Predictive tools, based on previous models and their comparison with experimental data, will be created to predict the behaviour of Wharton's jelly when placed in the body. - A comparison with experimental data, including MRI data, will be proposed to estimate the robustness of these predictive tools.

On a more fundamental level, the role of the microstructure and/or biochemical composition of the different phases on the mechanical behaviour of Wharton's jelly samples will be studied.

Compétences

Predictive simulation will be developed using finite element analysis (FEA) between LMGC, ICube and LEM3. Experience in poro-mechanical simulation is therefore an asset (Le Floc'h, et al., 2024). In addition, in vivo biological integration will be monitored using magnetic resonance imaging (MRI) at ICube. Knowledge of medical imaging and the creation of digital twins from medical images is therefore an asset for the position (Da Rocha et al., 2025a).


Bibliography:

A Baldit, M Dubus, J Sergheraert, H Kerdjoudj, C Mauprivez, and R Rahouadj. Biomechanical tensile behavior of human wharton's jelly. Journal of the Mechanical Behavior of Biomedical Materials, 126 :104981, 2022.

M-A Chetoui, D Ambard, P Canadas, P Kouyoumdjian, P Royer, and S Le Floc'h. Impact of extracellular matrix and collagen network properties on the cervical intervertebral disc responseto physiological loads : A parametric study.Medical Engineering & Physics, page 103908, 2022

Da Rocha, A., Bekrar, M., Kerdjoudj, H., Laurent, C.P., Mauprivez, C., Po, C., Baldit, A., 2024. A first viscoelastic modelling of Wharton's jelly membrane through finite element analysis, in: Proceedings of SB2024. Compiégne, France.

Da Rocha, A., Chatelin, S., Po, C., Laurent, C., Perroud, O., Kerdjoudj, H., Mauprivez, C., Baldit, A., 2025a. Preliminary results on multimodal mechanical characterization of a haemostatic sponge used for sinus lift. Multidisciplinary Biomechanics Journal

Da Rocha, A., Lavrand, A., Kerdjoudj, H., Laurent, C.P., Mauprivez, C., Po, C., Baldit, A., 2025b. First macro-scale damage properties for Wharton's jelly membrane undergoing tensile loading using finite element analysis, in: Proceedings of ESMC 2025. Lyon, France.

M Dubus, L Scomazzon, J Chevrier, A Montanede, A Baldit, C Terryn, F Quilès, C Thomachot-Schneider, S-C Gangloff, N Bouland, F Gindraux, H Rammal, C Mauprivez, and H Kerdjoudj. Decellularization of wharton's jelly increases its bioactivity and antibacterial properties. Frontiers in bioengineering and biotechnology, 10 :828424, 2022a.

M Dubus, L Scomazzon, J Chevrier, C Ledouble, A Baldit, J Braux,F Gindraux, C Boulagnon, S Audonnet, M Colin, H Rammal, C Mauprivez, and H Kerdjoudj. Antibacterial and immunomodulatory properties of acellularwharton's jelly matrix. Biomedicines, 10(2), 2022b.

Lavrand, A., Adam, L., Lemaire, F., Boulmedais, F., Baldit, A., Mauprivez, C., Brenet, E., Kerdjoudj, H., 2024. Osteocompatible tannic acid cross-linked wharton jelly hydrogel: new guide for bone regeneration, in: B-MRS 2024. Santos, Brazil.

Le Floc'h, S., Osquel Perez Rivero, E., Cavinato, C., Kerdjoudj, H., Baldit, A., 2024. Stratégie numérique pour de identifier les propriétés poro-hyperélastiques d'un dérivé de gelée de Wharton: résultats préliminaires, in: Réunion Annuelle Du GDR MécaBio Santé 2024. Metz, France.

L Scomazzon, M Dubus, J Chevrier, J Varin-Simon, J Braux, A Baldit, S Gangloff, C Mauprivez,F Reffuveille, and H Kerdjoudj. Use of crosslinked wharton's jelly in guided bone regeneration. Orthopaedic Proceedings, 103, supp 13 :81–81, 2021.

L Scomazzon, C Ledouble, M Dubus, J Braux, C Guillaume, N Bouland, A Baldit, F Boulmedais, V Gribova, C Mauprivez, and H Kerdjoudj. An increase in wharton's jelly membrane osteocompatibility by a genipin crosslink. International Journal of Biological Macromolecules, 255 :127562, 2024.

Contexte de travail

This position is part of an ANR project (2023-2027) entitled 'Hydro-chemical-mechanical characterisation of a mucoid matrix for medical applications'. The consortium's knowledge of Wharton's jelly (WJ) derivatives, which exhibit good biomechanical repeatability (Baldit et al, 2022; Dubus et al., 2022a, 2022b) and allow for the modulation of cross-linking (Scomazzon et al., 2024), GAG content (Scomazzon et al., 2021) and/or environment, is an asset for characterising hydro-chemical-mechanical couplings in soft biological tissues. Furthermore, as a product intended for destruction and promising for future medical applications, enriching knowledge about hydro-chemical-mechanical couplings in WJ appears to be crucial for medical innovation.

Contraintes et risques

This position will require traveling between Montpellier (LMGC) and Strasbourg (ICube).