A Droplet Microfluidic System to Fabricate Hybrid Capsules Enabling Stem Cell Organoid Engineering

Organoids derived from self‐organizing stem cells represent a major technological breakthrough with the potential to revolutionize biomedical research. However, building high‐fidelity organoids in a reproducible and high‐throughput manner remains challenging. Here, a droplet microfluidic system is developed for controllable fabrication of hybrid hydrogel capsules, which allows for massive 3D culture and formation of functional and uniform islet organoids derived from human‐induced pluripotent stem cells (hiPSCs). In this all‐in‐water microfluidic system, an array of droplets is utilized as templates for one‐step fabrication of binary capsules relying on interfacial complexation of oppositely charged Na‐alginate (NaA) and chitosan (CS). The produced hybrid capsules exhibit high uniformity, and are biocompatible, stable, and permeable. The established system enables capsule production, 3D culture, and self‐organizing formation of human islet organoids in a continuous process by encapsulating pancreatic endocrine cells from hiPSCs. The generated islet organoids contain islet‐specific α‐ and β‐like cells with high expression of pancreatic hormone specific genes and proteins. Moreover, they exhibit sensitive glucose‐stimulated insulin secretion function, demonstrating the capability of these binary capsules to engineer human organoids from hiPSCs. The proposed system is scalable, easy‐to‐operate, and stable, which can offer a robust platform for advancing human organoids research and translational applications.