Electrical wound-healing assay for cells in vitro

Confluent cell monolayers in tissue culture are fragile and can easily be mechanically disrupted, often leaving an area devoid of cells. This opening in the cell sheet is then repopulated, because the cells on the fringe of the damage, which are no longer contact-inhibited, move into the available space. This mechanical disruption is often done deliberately in a wound-healing assay as a means to assess the migration of the cells. In such assays, a scrape is made in the cell layer followed by microscopy to monitor the advance of the cells into the wound. We have found that these types of assays can also be accomplished electrically. In this approach, cells growing on small electrodes and monitored by using electric cell-substrate impedance sensing are subjected to currents, resulting in severe electroporation and subsequent cell death. After this invasive treatment, the electrode's impedance is again monitored to chart the migration and ultimate healing of the wound. We report here that this procedure to study cell behavior is both highly reproducible, quantitative, and provides data similar to that acquired with traditional measurements.