Sandcastles and surprising origins of basic cellular functions

Cells comprising a tissue can pack into disorderly geometries much as do grains of sand in a sandcastle. In doing so they can freeze into a fixed shape—as in a sandcastle—or flow like sand poured from a beach bucket. The finding, reported by researchers at Harvard T.H. Chan School of Public Health, Northeastern University, and MIT, provides insights into organ formation in an embryo, healing of a wound, and even invasion of cells into surrounding tissue, as occurs in cancer.