Inflammatory bowel disease (IBD) arises from chronic dysregulation at the epithelial–stromal interface, creating a need for in vitro systems that better capture these interactions. In this study, we developed a 3D co-culture platform in which HT-29 intestinal epithelial cells and IMR-90 fibroblasts are embedded within an alginate–gelatin hydrogel, alongside a complementary interface model using a plasma-treated electrospun mesh to spatially compartmentalize stromal and epithelial layers. We first assessed metabolic activity, viability, and proliferation across several epithelial-to-fibroblast ratios and identified 1:0.5 as the most supportive of epithelial expansion. The A1G7 hydrogel maintained high viability (>92%) and sustained growth in all mono- and co-cultures. To evaluate inflammatory competence, models were stimulated with lipopolysaccharide (LPS), administered either within the hydrogel or through the culture medium. LPS exposure increased TNF-α and IL-1β secretion in both configurations, with the magnitude of the response depending on the delivery route. Treatment with dexamethasone consistently reduced cytokine levels, confirming the model’s suitability for pharmacological testing. Together, these results demonstrate that the alginate–gelatin system provides a reproducible epithelial–stromal platform with quantifiable inflammatory readouts, offering a practical foundation for mechanistic studies and early-stage screening of anti-inflammatory therapeutics in IBD.

Femtosecond laser texturing is a promising surface functionalization technology to improve the integration and durability of dental and orthopedic implants. Four different surface topographies were obtained on Titanium-6Aluminum-4Vanadium plates by varying laser processing parameters and strategies: surfaces presenting nanostructures such as Laser-Induced Periodic Surface Structures (LIPSS) and ‘spikes’, associated or not with more complex multiscale geometries combining micro-pits, nanostructures and stretches of polished areas. After sterilization by heat treatment, LIPPS and spikes were characterized to be highly hydrophobic, whereas the original polished surfaces remained hydrophilic. Human mesenchymal stem cells (hMSCs) grown on simple nanostructured surfaces were found to be less spread with an increased motility (velocity, acceleration, tortuosity), while on the complex surfaces, hMSCs decreased their migration when approaching the micro-pits and preferentially positioned their nucleus inside them. Moreover, focal adhesions of hMSCs were notably located on polished zones rather than on neighboring nanostructured areas where the protein adsorption was lower. All these observations indicated that hMSCs were spatially controlled and mechanically strained by the laser-induced topographies. The nanoscale structures influence surface wettability and protein adsorption and thus influence focal adhesions formation and finally induce shape-based mechanical constraint on cells, known to promote osteogenic differentiation [1].

Cette thèse traite des problèmes d'infections des implants dentaires, telles que la péri-implantite, causées par l'adhérence de bactéries parodontopathogènes. Elle explore l'utilisation de la texturation laser femtoseconde (fs-L) pour améliorer les propriétés des surfaces d'implants en alliage de titane (Ti6Al4V).Le projet, financé par l'ANR et mené en collaboration avec divers laboratoires, a utilisé des techniques de caractérisation avancées pour analyser les surfaces texturées et évaluer leur efficacité en conditions biologiques. Les résultats montrent que la texturation par fs-L permet de créer des structures de surface périodiques (LIPSS) micro et nanométriques, modifiant la surface de contact et par conséquent l’adhérence cellulaire et bactérienne. Les surfaces ainsi texturées ont démontré une réduction significative de l'adhérence des bactéries parodontopathogènes, telles que Porphyromonas gingivalis, réduisant ainsi potentiellement les risques de péri-implantite.Les études in vitro ont également confirmé une meilleure adhérence des fibroblastes gingivaux sur les surfaces texturées, ce qui pourrait réduire les risques d’infiltration bactérienne et ainsi améliorer la stabilité et l’intégration des implants.En conclusion, la texturation laser femtoseconde des surfaces d'implants dentaires est prometteuse pour créer des implants plus durables et doublement fonctionnalisés, améliorant l'adhérence cellulaire et possédant des propriétés antibactériennes accrues. Ces avancées ouvrent la voie à des implants répondant mieux aux défis cliniques actuels tout en contribuant à la lutte contre l'antibiorésistance. Des études supplémentaires plus proches d'une situation clinique sont prévues pour valider ces résultats et explorer les interactions entre les topographies fs-L et les réponses biologiques des tissus environnants.