Monitoring the permeabilization of a single cell in a microfluidic device, through the estimation of its dielectric properties based on combined dielectrophoresis and electrorotation in situ experiments

The electric field is commonly used in microdevices to handle, treat, or monitor living cells for various biological or biomedical applications (cells electrofusion, gene electrotransfer, drugs injection, cell sorting, ...). Dielectrophoresis (DEP) forces, using stationary waves (conventional DEP) or traveling waves, are widely used for the cell handling or sorting. Electrorotation, which is induced by a rotating electrical field, is used for the determination of cell dielectric parameters. The application of pulsed electric field (PEF) results in the cell membrane permeabilization that might allow the transfer of various molecules in the cytoplasm. In this paper, we propose a method to monitor in situ the level of electropermeabilization induced by PEF application on a single cell, by combining the dielectrophoresis force and the electrorotation torque within a microfluidic device. The method was experimented on two different cell lines (human leukemic T-cell lymphoblast and murine melanoma cell): a single cell is captured by dielectrophoresis while its dielectric properties (both permittivity and conductivity of cytoplasm and membrane) are estimated thanks to a rotating electric field, which is applied simultaneously. The permeabilization effect of PEF, applied to the single cell trapped in such conditions in the biodevice, could be monitored by the estimation of its dielectric properties before and after pulse application.