Enhancement Effect of Urea Toward Electroporation-mediated Plasmid Transfection Efficiency in HEK-293 Cell Line

Electroporation is one of the most widely used physical transfection methods, which induces transient pores in the cell membrane, by applying an external electric field. Unsatisfied transfection efficiency and low cell viability are the major drawbacks of electroporation. The impact of chemical enhancers to overcome these issues is not fully recognized. Thus, we decided to investigate the effect of urea as a low-cost chemical enhancer buffer on electroporation-mediated transfection efficiency. To this end, three voltages of electroporation including 100, 120, and 140 V as well as three concentrations of urea buffer including 0.25%, 0.5%, and 1% W/V were considered as our variables. GFP expression in HEK-293 cell line was evaluated using flow cytometry and fluorescence microscopy. Our results indicated that voltage as a key parameter has a significant effect on cell behavior against the synergistic effects of electroporation and urea. The addition of urea to the cells at the voltage of 100 increased the number of cells expressing GFP. In this regard, further to acceptable cell viability (over 90%), the 0.5% W/V of urea at the voltage of 100 had the highest transfection efficiency (23.3 ± 0.3%), a nearly two-fold increase compared to the untreated transfected cells (12.3 ± 0.2%). In conclusion, the combination of electroporation and urea elevated the efficacy of electroporation. However, the effect depended on the voltage and urea concentration. We believe that our study would give researchers new insights into the achievement of improved gene transfection efficiency when they utilize electroporation.