Cell electrotransfection and viability dependence on electrotransfection and viability dependence on electoporation medium

Electroporation is a physical method that uses electric fields to increase membrane permeability. The method is widely used for intracellular drug and gene delivery. In this study we aimed to investigate the importance of the medium for efficiency of cell electrotransfection and viability following the application of electric field pulses. The experiments were performed using 2 different cell lines: Chinese hamster ovary (CHO) and Chinese hamster lung fibroblast (DC-3F) and 2 different electroporation media: SMEM (medium conductivity equal to 1.3 S/m) and laboratory-made low-conductivity (0.1 S/m) electroporation (EP) medium. Cells suspended in these media were supplemented with plasmid (10 µg/ml) encoding luciferase and then were treated with 1, 5, or 10 high-voltage (1200 V/cm, 100 µs, at 1 Hz) pulses. Transfection efficiency was determined by luciferase activity 24 h after cell treatment, while cell viability was determined by clonogenic assay. Results showed significant differences between cell lines and used electroporation media. CHO transfection was higher when electroporation was performed in low conductivity EP medium. Low transfection efficiency in SMEM medium resulted from low viability. In contrast, transfection efficiency of DC-3F cells was higher in SMEM. Possible mechanisms governing these differences are discussed.