Electric Cell Substrate Impedance Sensing (ECIS) Wounding (Migration) Assay

Cell resistance was measured using the electric cell–substrate impedance sensing system (ECIS; Applied BioPhysics, Troy, NY). Cells are cultured onto gold electrodes and impedance values recorded, which are transformed to both resistance and capacitance values. As cells grow and become confluent, they constrict current flow through the electrodes and alter impedance²⁹. Nuli-1 cells were grown to confluence on ECIS 96-well plate arrays (8W1E; Applied Biophysics, Troy NY). Cell monolayer were wounded using an elevated field pulse of 1400 μA at 32,000 Hz applied for 20 sec, producing a uniform circular lesion 250 μm in size. The wounds were tracked over a period of 24 h. The impedance was measured at 4000 Hz, and the transepithelial resistance (TEER; ohms) normalized relative to the value at the start of data acquisition previous to treatments, and plotted as a function of time.