Mechanoregulatory Effects of Cell‐Scale Microwells on Epithelial Cell Phenotype

ABSTRACT Substrate topography regulates epithelial cell behavior, yet how feature size relative to cell dimensions affects mechanotransduction remains poorly understood. Herein, polycaprolactone (PCL) substrates are fabricated in three topographies with controlled sizes through solvent casting, including flat controls (PCL‐400), large (PCL‐200, ∼37 µm), and small microwells (PCL‐111, ∼12 µm). Human lung epithelial A549 cells are used to explore scale‐dependent mechanoregulatory effects on morphology and biochemical signaling. Small microwells trigger mechanotransduction cascade responses that are absent in larger, flat features. In small microwells, cells adopt a bridging strategy, spanning across edges rather than conforming to the microwell geometry. This geometric constraint leads to the reorganization of focal adhesions into concentrated clusters at topographic boundaries. Mechanical generation of localized cytoskeletal tension causes nuclear deformation, with nuclear sphericity decreasing monotonically (PCL‐400 > PCL‐200 > PCL‐111) as the topographic constraint increases. Nuclear deformation was accompanied by reduced expression of stiffness‐regulating protein Lamin A/C, suggesting an adaptive softening response. The resulting increase in nuclear plasticity likely induces a mechanical priming state that enhances cellular sensitivity to biochemical signals. These findings demonstrate that cell‐scale geometric constraints alone can drive phenotypic changes in epithelial cells, highlighting their implications for the development of mechanically informed materials and tissue scaffolds.