Electroporation for transfection and differentiation of dental pulp stem cells

Target gene delivery is needed to induce cellular differentiation or a specific therapeutic effect. Electroporation is a relatively safe and simple technique to deliver nucleic acids to the cell that acts by rendering cells transiently permeable using short periods of high voltage. In stem cell research, human dental pulp stem cells (hDPSCS) are highly accessible, and they exhibit broad differentiation potential. Until now, no studies have attempted to optimize electroporation parameters for DPSCs with respect to transfection efficiency and viability. In this study, we aimed to optimize transfection of DPSCs through varying different electroporation parameters, including voltage, mode of pulsation, and the number of pulses. As positive control, we used commonly utilized the chemical transfection reagents Lipofectamine 2000 and FuGene 6. In addition, we used our newly optimized transfection conditions to transfect hDPSCs with a functional chondrogenic transgene. We obtained higher transfection efficiency and cell viability with these electroporation conditions compared to controls. The highest transfection efficiency (63.81±4.72%) was achieved with 100 V, 20 msec, one-pulse square-wave condition. Among chemical transfection groups, FuGene 6 showed the highest cell viability at all tested transfection ratios, while Lipofectamine 2000 showed the highest transfection efficiency (19.23±3.19%) using 1:1 DNA (μg):Lipofectamine (μL). Transfected DPSCs functionally expressed the transforming growth factor β-3 chondrogenic transgene on the mRNA level as detected by real-time polymerase chain reaction and on the protein level as detected by Western blot analysis. An increase in various chondrogenic markers was also found when studying mRNA expression in transfected cells. In conclusion, the results of our study demonstrate optimal electroporation and chemical transfection reagent conditions for hDPSCs, and, subsequently, we provide proof of concept for expression of a functional gene using those conditions. These results demonstrate a widened scope for use of DPSCs in various tissue engineering applications.