An Ex-Vivo Niche Model for Culturing Multicellular Structures in 3D Patterned Microenvironments
Abstract: The stem cells niche is a regulatory element promising ultimate control over stem cells fate and organization. Current culturing systems target yet seldom recapitulate in-vivo niche hallmarks. In this talk I will present a novel niche model realized using a micro-bio-reactor. This reactor provides dynamic control over patterning signals' composition and gradients across the length-scale of small multi-cellular structures such as embryos and embryoid bodies (EBs). The structure comprises a central culturing volume filled with biodegradable / support scaffold and peripheral 3D-printed components and facilitates long-term confocal microscopy, live-marker analysis, online metabolite collection and sample retrieval for offline analyses. I will describe the design parameters, present molecular gradients that agree with predictions from theoretical and numeric (finite element) solutions of the Diffusion Equation and demonstrate long-term culturing and monitoring of human EBs. For these EBs, I will show that ~50 µm cell-clusters/cysts migrate at a speed of ~10 µm/hr; a significantly higher than observed before speed – indicating the EB high plasticity. I will also present villous formation (syncytialization) of mouse and bovine embryos cultured with primary endometrium and an implantation model based on human Trophectoderm and Endometrium cell lines, recapitulating trophoblast invasion and hCG secretion. The novel platform is more economical than microfluidic devices, scalable, reproducible, fabricated without human intervention and amenable to mass-production. It constitutes a well-defined microenvironment supplementary to animal models. Furthermore, this platform may facilitate the establishment of external organizing centers, which mimics in-vivo processes, and guide embryonic structures differentiation towards required therapeutic tissues.