Développement d'un « Intestin-sur-puce » pour étudier les infections par la levure pathogène opportuniste Candida avec microscopie optique avancée et personnalisée

Conventional models, such as cells cultured in Petri dishes or Transwell inserts, often fail to replicate the complex physiology of the human body. At the same time, the use of animal models is increasingly avoided due to ethical concerns and their limited translational relevance to human biology. Organs-on-chip (OOCs) offer a promising alternative by creating biomimetic environments that model organ functionality and recapitulate key physiological and pathological features under controlled conditions.This thesis addresses a critical limitation of current OOC designs—the difficulty of observing real-time cellular events under flow conditions within a culture-compatible environment. The primary objective is to develop a next-generation OOC that more closely mimics in vivo conditions by enabling the application of external mechanical cues, specifically fluidic shear stress. The project focuses on the design, fabrication, and detailed characterization of a microfluidic device incorporating a central porous membrane. Two membrane materials, PDMS and collagen type I, are thoroughly evaluated to determine which better supports physiologically relevant cell growth, with collagen type I emerging as the optimal choice.Following integration of the collagen type I membranes into the system, Caco-2 cells were introduced into the upper channel. After seven days under constant flow, the cells formed an epithelial layer displaying villi-like structures, confirmed by scanning electron microscopy (SEM). Morphological characterization by confocal microscopy further verified the presence of tight junctions, cellular polarization, differentiation, and mucus production. Additionally, the apparent permeability of the obtained epithelium decreased compared to that of the collagen membrane alone.Building on this platform, a proof-of-concept study was conducted to model intestinal infection by the pathogenic yeast Candida albicans. The study included morphological characterization of the intestinal epithelial layer using markers such as ZO-1 to assess tight junction damage following infection. SEM was employed to observe infected cells and yeast invasion, while permeability assays evaluated intestinal barrier integrity after Candida albicans infection. An increase in apparent permeability was observed following infection. This model enables detailed investigation of the infection process and its effects on the intestinal epithelium, paving the way for future projects aimed at developing more complex systems.