Mechanical Interactions Govern Self-Organized Ordering in Two-Dimensional Bacterial Colonies

Abstract: We investigate the influence of mechanical interactions on the growth and self-organization of rod-shaped bacteria confined within square and circular geometries. Our results reveal that mechanical interactions are crucial in constraining cell growth and shaping the degree of ordering within bacterial colonies. Colonies with larger aspect ratios exhibit higher levels of nematic ordering, while the geometry of confinements significantly impacts colony organization. Compression influences force magnitudes within colonies, with larger division lengths encountering greater forces. These findings enhance our understanding of bacterial self-organization in confined environments, with implications for microbial ecology and biotechnology.