Nanosecond Electric Pulse Effects on Gene Expression

The Author(s) 2013. This article is published with open access at Springerlink.com Abstract Gene electrotransfection using micro- or mil-lisecond electric pulses is a well-established method for safe gene transfer. For efficient transfection, plasmid DNA has to reach the nucleus. Shorter, high-intensity nanosec-ond electric pulses (nsEPs) affect internal cell membranes and may contribute to an increased uptake of plasmid by the nucleus. In our study, nsEPs were applied to Chinese hamster ovary (CHO) cells after classical gene electro-transfer, using micro- or millisecond pulses with a plasmid coding the green fluorescent protein (GFP). Time gaps between classical gene electrotransfer and nsEPs were varied (0.5, 2, 6 and 24 h) and three different nsEP parameters were used: 18 ns-10 kV/cm, 10 ns-40 kV/cm and 15 ns-60 kV/cm. Results analyzed by either fluores-cence microscopy or flow cytometry showed that neither the percentage of electrotransfected cells nor the amount of GFP expressed was increased by nsEP. All nsEP parame-ters also had no effects on GFP fluorescence intensity of human colorectal tumor cells (HCT-116) with constitutive expression of GFP. We thus conclude that nsEPs have no major contribution to gene electrotransfer in CHO cells and no effect on constitutive GFP expression in HCT-116 cells