3D-printed toolkit for regulating epithelial unjamming

During wound healing and cancer invasion, epithelial monolayers transition from a solid-like, jammed state to a fluid-like unjammed state. However, affordable and accessible tools for modeling and precise tuning of this response remain limited. Here, we present a simple, lithography-free 3D-printed toolkit of customizable inserts and scratchers for fabricating micro-gaps with defined geometries and widths down to ∼50 µm, without requiring cleanroom facilities or specialized expertise. Using epithelial monolayers, we demonstrate that gap width fundamentally regulates unjamming dynamics. Narrow gaps induced rapid, coordinated migration with high initial velocities, whereas wide gaps suppressed early unjamming and produced slower, spatially heterogeneous closure. Cell shape dynamics confirmed conserved elongation, cell rounding, and closure behaviors across conditions. The presented toolkit provides new opportunities for investigating the mechanical and molecular mechanisms that regulate epithelial plasticity, enabling fine control of unjamming transitions and allowing the modeling of both healthy and pathological wound-response regimes.