The three-dimensional (3D) organization of EBs generated in vitro from mouse embryonic carcinoma cells was reminiscent of early embryonic structures, as it comprised cells from all three primary germ layers. The first report of embryoid bodies (EBs) dates back to the mid-seventies, before the advent of embryonic stem cell (ESC) research. In this review, we summarize how EB formation is accompanied by a variety of biomechanical parameters that need to be considered for the directed and reproducible self-organization of early cell fate decisions. Furthermore, hydrogels can be used to better control the organization and lineage-specific differentiation of EBs. Epithelial structures outside and inside EBs support the integrity of the cell aggregates and counteract mechanical stress. There is a growing perception that the mechanical properties, cell mechanics, and cell signaling during EB development are also influenced by physical cues to better guide lineage specification substrate elasticity and topography are relevant, as well as shear stress and mechanical strain. In the last few years, culture methods have further evolved to better control EB size, growth, cellular composition, and organization-e.g., by the addition of morphogens or different extracellular matrix molecules. Within few days, the cells undergo a transition from rather homogeneous epithelial-like pluripotent stem cell colonies into a three-dimensional organization of various cell types with multifaceted cellвЂ“cell interactions and lumen formation-a process associated with repetitive epithelial-mesenchymal transitions. Embryoid bodies (EBs) resemble self-organizing aggregates of pluripotent stem cells that recapitulate some aspects of early embryogenesis.

Embryoid body blood island