Nanoliter Hydrogel Array for Cell Screening and Cell Spheroid Sorting

Abstract The transition from two‐dimensional (2D) to physiologically relevant three‐dimensional (3D) cell models has revolutionized biomedical research. Hydrogels are frequently used to produce 3D models for tissue engineering, disease modeling, and high‐throughput screenings (HTS). However, integrating 3D cultures into HTS workflows presents challenges, including automation compatibility and cost constraints. Addressing these challenges requires innovative approaches that enable miniaturization, automation, and cost reduction while maintaining experimental fidelity. The Droplet Microarray platform, based on hydrophilic‐superhydrophobic surface patterning, facilitates the formation of nanoliter‐hydrogel arrays containing cells or spheroids. This method allows dispensing of hundreds of nanoliter‐hydrogel droplets with precise control over volume and cell density, reducing reagent consumption and offering high‐throughput applications. Here, we demonstrate stable nanoliter‐hydrogel arrays on a chip, enabling experimental procedures such as washing and medium immersion. Our approach demonstrates that spheroid‐containing droplets can be gelled at any point of the experiment, allowing for the fixation of cell structures on the surface. The selective gelation of individual droplets enables spheroid sorting by stabilizing desired droplets while pooling the others. This method holds the potential for HTS and miniaturized workflows in 3D microenvironments, thereby advancing research in different fields such as cell, cell spheroid, or organoid screenings, drug screenings, and precision medicine.