Cold plasma is emerging as a potential method for medical applications. The current study assessed the efficacy of a novel cold plasma reactor based on shielded sliding discharge producing cathode-directed streamers generated in ambient air for the delivery of plasmid DNA. Experiments were performed with mouse melanoma cells (B16F10) and human keratinocyte cells (HaCaT) inoculated with plasmid DNA encoding luciferase. Quantitative results measured over a 72-h period displayed luciferase expression levels as high as 5-fold greater in cells exposed to plasma-activated air (PAA) than levels obtained from the inoculation of plasmid DNA alone (P<0.05, P<0.01). No effect on cell viability was observed. Delivery of plasmid encoding GFP to HaCaT cells seeded on polycaprolactone (PCL) scaffolds was confirmed by immunostaining. The use of cold plasma for DNA delivery is attractive as it provides a non-viral, non-invasive method where the electrode or the plasma itself never directly contacts the exposed site. The current device design provides localized DNA transfer using a novel technology. Our report suggests PAA warrants further exploration as an alternative or supplemental approach for DNA transfer. Biotechnol. Bioeng. 2015;112: 2583-2590. (c) 2015 Wiley Periodicals, Inc.