Bioengineered pluripotent stem cell models: new approaches to explore early human embryo development

Human development is a complex process in which environmental signals and factors encoded by the genome interact to engender cell fate changes and self-organization that drive the progressive formation of the human body. Herein, we discuss engineered biomimetic platforms with controllable environments that are being used to develop human pluripotent stem cell (hPSC)-based embryo models (or embryoids) that recapitulate a wide range of early human embryonic developmental events. Coupled with genome editing tools, single-cell analysis, and computational models, they can be used to parse the spatiotemporal dynamics that lead to differentiation, patterning, and growth in early human development. Furthermore, we discuss ongoing efforts in human extraembryonic lineage derivation and what can be learned from mouse embryoid models that have used both embryonic and extraembryonic stem cells. Finally, we discuss promising bioengineering tools for the generation of more controllable systems and the need for validation of findings from hPSC-based embryoid models.