Cell migration: Electrifying movement

Daniel Cohen and colleagues report that galvanotaxis, where living cells, both eukaryote and prokaryote, undergo motion in response to weak electric fields, can be used to control the collective migration of cells on a flat substrate. Using lithography to design the shape of the electrodes and the geometric constraints of the cellular layer, the approach of Cohen and colleagues allows for the exploration of cellular dynamics with very complex spatiotemporal regulation. From the electric field oscillations, the authors were able to measure the time that it takes for the collective motion of the layer to set in, that is, for all the patches to merge into a single coherent migration flow. This is found to be of the order of 10-30 min, which is the time it takes for cellular orientational ordering to propagate across the length of the rotating patches. Cohen and collaborators find that the leader cells are rather oblivious to the applied electric field and that they do not respond to it as do cells within the bulk of the layer.