Figure 1. xCELLigence RTCA: impedance-based detection of cell viability and motility.
Interdigitated gold microelectrodes on the well bottom (viability – E-plate) or on the bottom side of a filter membrane (motility – CIM-plate 16) detect impedance changes, caused by the presence of cells and expressed as a Cell Index. This detection method is proportional to both cell number (left and above) and morphology as increased cell spreading is reflected by a higher Cell Index value (right). When starting an experiment, a baseline Cell Index value is recorded in medium only before cell addition.