This illustration shows how ice invades the space between two cells, an event that triggers crystallization of the cell water. The view shown here is a cross-section through the interface where the two cells meet. So-called tight junctions, which are depicted as small spheres arranges in rows, are embedded in the cell membrane and form seams that stitch the two cells together. Although these seams normally act as barriers that prevent ice from invading the tissue, the research by Higgins and Karlsson demonstrated that if the temperature is sufficiently low, extracellular ice can penetrate through nanoscale openings in the tight junction seams. As a result, the cells in the vicinity of the breach become much more susceptible to freezing damage.