Measurement of cell-substrate impedance and characterization of cancer cell growth kinetics with mathematical model

Non-invasive cell-substrate impedance sensing technique was used to monitor cancer cell attachment, spreading and proliferation as function of culture time. Impedance values were measured with cells cultured on collagen coated surface which exhibited moderate contact angle (54.5) and positively charge surface with the zeta potential (ζ) of +3.91 mV. Impedance was gradually increased and reached steady state after 2.6 hrs and 2.9 hrs with different impedance for SCC7 (2.7 Ω) and HeLa cells (1.1 Ω) respectively. Modified Gompertz mathematical growth model was used to determine growth kinetics, and showed maximum growth rate (μm) for SCC7 (7.9×10−4 hr−1) and HeLa cells (2×10−5 hr−1) as well as both cells showed exponential increase of impedance following the lag period (λ) which required for cells to recover from the trypsinization and initiate attaching on electrode surface. The duration of lag period for SCC7 (0.7 hr) and HeLa cells (0.25 hrs ) demonstrated that HeLa cells exit lag period earlier than SCC7 cells and enter exponential growth which supports the rapid attachment and spread on substrate. Our result supported that the impedance measurement revealed cell-type specific growth characteristics and electrophysical properties that would be used to determine meaningful fingerprint for cancer cell study.