Nanosecond range electric pulse application as a non-viral gene delivery method: proof of concept

Abstract

Current electrotransfection protocols are well-established for decades and, as a rule, employ long micro-millisecond range electric feld pulses to facilitate DNA transfer while application of nanosecond range pulses is limited. The purpose of this paper is to show that the transfection using ultrashort pulses is possible by regulating the pulse repetition frequency. We have used 200ns pulses (10–18kV/ cm) in bursts of ten with varied repetition frequency (1Hz–1MHz). The Chinese Hamster Ovary (CHO) cells were used as a cell model. Experiments were performed using green fuorescent protein (GFP) and luciferase (LUC) coding plasmids. Transfection expression levels were evaluated using fow cytometry or luminometer. It was shown that with the increase of frequency from 100kHz to 1MHz, the transfection expression levels increased up to 17% with minimal decrease in cell viability. The LUC coding plasmid was transferred more efciently using high frequency bursts compared to single pulses of equivalent energy. The frst proof of concept for frequency-controlled nanosecond electrotransfection was shown, which can fnd application as a new non-viral gene delivery method.