Nguyen, Quoc Huynh

ABSTRACT Encapsulation of human pluripotent stem cells (hPSC) has high relevance for biomedical applications ranging from tissue engineering to drug screening and cellular therapies. Microcapsules serve a multitude of purposes—from promoting hPSC organization into spheroids to enabling scalable differentiation in vitro and providing immunoisolation in vivo. While multiple encapsulation strategies have been reported, there is typically a tradeoff between the structural complexity of capsules and throughput of their generation. Our paper describes a novel 3D printed microfluidic encapsulation device for fabricating structurally complex microcapsules with a hydrogel shell and aqueous core at rates of up to 1825 Hz. The use of 3D printing allowed to dramatically decrease device footprint when compared to standard soft lithography‐based microfluidic encapsulation devices. Leveraging decreased footprint and the ability to arrange fluidic networks in a 3D space, we fabricated a 10‐nozzle microencapsulation device that generated microcapsules at a rate 10‐times that of the single‐nozzle device. The novel microfluidic device was used to encapsulate hPSCs, human embryonic stem cells (hESCs), and induced pluripotent stem cells (iPSCs). Hydrogel microcapsules with aqueous core promoted hPSCs aggregation into spheroids or embryoid bodies, which maintained high levels of pluripotency. Our technology enables safe and effective encapsulation of hPSCs on a scale (billions of cells) required to treat patients.