Real-time electrical impedance detection of cellular activities of oral cancer cells.

In this study, the electric cell-substrate impedance sensing (ECIS) system was used to study the cellular activities of oral squamous cell carcinoma (OSCC) cells in a real-time and label-free manner. Various cellular activities, including cell adhesion, spreading, proliferation, and drug-induced apoptosis and inhibition of apoptosis, were monitored. A linear relationship was found between the impedance-based cell index and the cell number in the range of 3500 to 35,000 cells/well. Anti-cancer drug-cisplatin-induced OSCC cell apoptosis at the minimal concentration of 5 microM after 20 h of treatment and followed a linear dose-dependent manner in the concentration range from 10 microM to 25 microM. The inhibition of cisplatin-induced apoptosis by the carcinogen, nicotine, at concentrations from 0.1 microM to 10 microM was monitored. The most significant inhibitory effect of nicotine on cisplatin-induced apoptosis was observed at concentrations of 0.5-1 microM. The results obtained with impedance method correlated well with microscopic imaging analysis of cellular morphology and cell viability analysis. This study demonstrated that the impedance-based method can provide real-time information about the cellular activity of viable cells and detect drug-induced cellular activities much earlier than commonly used cell-based image analysis. This impedance-based method has the potential to provide a useful analytical approach for cancer research.