Tunable Hydrogel Confinement via On-Chip 3D Printing for Studying Cancer Cell Migration

The physical confinement of the extracellular matrix (ECM) has been proven to be a coconspirator in cancer metastasis. However, current experimental models are limited in accurately dissecting the effect of mechanical and topographical properties on cancer cell migration in a confined three-dimensional (3D) environment. In this study, we propose a facile strategy to produce precisely controlled channel-like hydrogel confinements on a microfluidic device via a "hydrogel-in-hydrogel" two-photon 3D printing approach. Within this model, it is demonstrated that breast cancer cells migrate faster in the stiffer confinements with an adapted migratory phenotype, and the transcriptomic profile of the migrating cells shows that the activation of YAP is involved in this process. This platform allows the fabrication of high-resolution hydrogel microstructures, real-time observation of the cell-environmental interplay, and convenient collection of migrating cell samples for sequencing analyses, which provides a powerful tool for investigating cell migration and mechanical interactions within a confined microenvironment.