Real-time electrical impedance-based measurement to distinguish oral cancer cells and non-cancer oral epithelial cells

In this study, electrical impedance-based measurements were used to distinguish oral cancer cells and non-cancer oral epithelial cells based on their cellular activities on the microelectrodes in a real-time and label-free manner. CAL 27 and Het-1A cell lines were used as the models of oral cancer cells and non-cancer oral epithelial cells, respectively. Various cellular activities, including cell adhesion, spreading, and proliferation were monitored. We found that both the kinetics of cell spreading and the static impedance-based cell index were feasible to distinguish the two cell types. At each given cell number, CAL 27 cell spreading produced a smaller cell index change rate that was 60–70% of those of Het-1A cells. When cells were fully spread, CAL 27 cells generated a cell index more than four times greater than that of Het-1A cells. Since cell spreading and attachment occurs in the first few hours when they were cultured on the microelectrodes, this impedance-based method could be a rapid label-free and non-invasive approach to distinguish oral cancer cells from non-cancer oral epithelial cells. Cell viability analysis was performed along with the impedance-based analysis. Confocal microscopic imaging analysis showed the difference in cell morphology and the thickness of cell monolayers between the two cell types.