Engineering neurovascular organoids with 3D printed microfluidic chips

The generation of tissues and organs requires close interaction with vasculature from the earliest moments of embryonic development. Tissue-specific organoids derived from pluripotent stem cells allow for the in vitro recapitulation of elements of embryonic development, however they are not intrinsically vascularized, which poses a major challenge for their sustained growth and for understanding the role of vasculature in fate specification and morphogenesis. Current organoid vascularization strategies do not recapitulate the temporal synchronization and spatial orientation needed to ensure in-vivo-like early co-development. Here, we developed a human pluripotent stem cell (hPSC)-based approach to generate organoids which interact with vascular cells in a spatially determined manner. The spatial interaction between organoid and vasculature is enabled by the use of a custom designed 3D printed microfluidic chip which allows for a sequential and developmentally matched co-culture system. We show that on-chip hPSC-derived pericytes and endothelial cells sprout and self-assemble into organized vascular networks, and use cerebral organoids as a model system to explore interactions with this de novo generated vasculature. Upon co-development, vascular cells interact with the cerebral organoid and form an integrated neurovascular organoid on chip. This 3D printing-based platform is designed to be compatible with any organoid system and is an easy and highly cost-effective way to vascularize organoids. The use of this platform, readily performed in any lab, could open new avenues for understanding and manipulating the co-development of tissue-specific organoids with vasculature. ### Competing Interest Statement The authors have declared no competing interest.