Monitoring Electropermeabilization of Adherent Mammalian Cells Through Electrochemical Impedance Spectroscopy

In this work, cell adhesion and electroporation effects have been studied through impedance measurements. Chinese Hamster Ovary (CHO-K1) cells have been plated and grown adherent to multi-electrode arrays and then stimulated to obtain the electroporation. We used Electrochemical Impedance Spectroscopy (EIS) measurements to analyze the impedance variation that occurs with cell adhesion and, consequently, to obtain the intrinsic electrical parameters of the electrode-cell interface through a lumped parameter model. The whole model allows to estimate the correction factor β and the sealing resistance R_seal, both dependent on the cell coverage and adhesion. The electroporation has been performed after cell adhesion, using a custom stimulation bench, able to evaluate the cell-electrode coupling and to stimulate an individually addressable site. By performing EIS measurements, before and after the electroporation, cell status, adhesion and membrane resistance can be detected. From measurements, an impedance decrease as a function of pulse amplitude can be noted. The proposed equivalent electrical model allows to evaluate the variation in membrane conductance due to pores formation. Moreover, average pore radius between 0.5 nm and 2.2 nm, increasing with pulse amplitude, was estimated.