Impedimetric characterization of normal and cancer cell responses after nano-pulse stimulation

Abstract

Abstract This work aimed to investigate the potential selective effects of nano-pulse stimulation (NPS) on adherent cancer and normal cells using impedance spectroscopy. A constant phase element was used to separate the impedance of electrode polarization from the overall measured impedance. Its amplitude was further related to cell-to-substrate distance, D cs, which describes the gap between cells and substrate. Dielectric properties of subcellular components were extracted based on a single-shell dielectric model for individual cells and were consequently used to calculate the induced transmembrane potentials (TMPs). Afterward, a Cole–Cole model was utilized to represent the impedance of cell monolayers. The model parameter, R 0, representing resistance at low frequency, was related to the paracellular distance, D cc. Results showed that cancer cells could suffer a higher degree of electroporation than normal cells when exposed to the same NPS. This selective NPS effect was reflected by a greater decrease of the Cole model parameter, α, and larger induced TMPs for cancer cells. D cc was pulse number-dependent for both types of cells after exposure (four and eight pulses, 100 ns, 660 V). D cs showed lingering effects even 24 h after exposure to 8 ns pulses for both cancer and normal cells, suggesting that intense NPS can induce long-term changes of the cell-to-substrate interface.