Emergence of Distinct Cell Morphology and Size of Confluent Cell Sheet

Collective migration of epithelial sheets underlies processes from wound healing to cancer invasion. A striking but poorly understood feature of migrating epithelia is their emergent heterogeneity: peripheral cells stretch and elongate while bulk cells remain compact and ordered. Here, we introduce a novel stochastic particle–Voronoi framework that enables size and shape heterogeneity to emerge from mechanical interactions alone, without the need for prescribed target geometries. Peripheral cells emerge larger, more irregular, and more polarized, while bulk cells remain smaller and more hexagonal. Tuning division thresholds and neighbor coupling strength reveals simple rules that link local mechanics to global morphology. By connecting minimal dynamics to emergent tissue organization, our model offers a new lens on how epithelial monolayers coordinate structure and motion during collective migration.