Electrochemical impedance spectroscopic measurements of FCCP-induced change in membrane permeability of MDCK cells

This study demonstrates a new electrochemical impedance spectroscopic (EIS) method for measurements of the changes in membrane permeability during the process of cell anoxia. Madin-Darby canine kidney (MDCK) cells were employed as the model cells and were cultured onto gelatin-modified glassy carbon (GC) electrodes. EIS measurements were conducted at the MDCK/gelatin-modified GC electrodes with Fe(CN)(6)(3-/4-) as the redox probe. The anoxia of the cells grown onto electrode surface was induced by the addition of carbonycyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) into the cell culture, in which the MDCK/gelatin-modified GC electrodes were immersed for different times. The EIS results show that the presence of FCCP in the cell culture clearly decreases the charge-transfer resistance of the Fe(CN)(6)(3-/4-) redox probe at the MDCK/gelatin-modified GC electrodes, and the charge-transfer resistance decreases with increasing time employed for immersing the MDCK/gelatin-modified GC electrodes into the cell culture containing FCCP. These results demonstrate that the EIS method could be used to monitor the changes in the cell membrane permeability during the FCCP-induced cell anoxia. To simulate the EIS system, a rational equivalent circuit was proposed and the values of ohmic resistance of the electrolyte, charge-transfer resistance and constant phase elements for both the gelatin and the cell layers are given with the fitting error in an acceptable value. This study actually offers a new and simple approach to measuring the dynamic process of cell death induced by anoxia through monitoring the changes in the cell membrane permeability.