One-Step Generation of Core-Shell Gelatin Methacrylate (GelMA) Microgels Using a Droplet Microfluidic System

Gelatin methacrylate (GelMA) microgels are promising scaffolds for biological applications, such as tissue engineering and drug screening. Solid-like GelMA microgels are limited by undefined spatial structures and inadequate protection. In this study, a simple strategy is reported for the one-step generation of core-shell GelMA microgels using a droplet microfluidic system. A flow-focusing microfluidic device is fabricated to produce the core-shell microgels. The device operates the laminar flow of a photocurable GelMA solution and a templated methyl cellulose solution in the system. The size of the microgels is controlled by simply adjusting the flow rates. The good biocompatibility of the microgels is demonstrated by encapsulating liver cells into the cores, in which the cells show high viability for 15 d. The microgels are also successfully used to coculture the liver cells and vascular endothelial cells, indicating the core-shell architectures are suitable for heterogenous cell cultures. The proposed core-shell GelMA microgels have potential in various fields such as the construction of microtissues, generation of organoids, and fabrication of stimuli-responsive materials.