Needle-free topical electroporation improves gene expression from plasmids administered in porcine skin

Electroporation has been shown to increase the potency of DNA vaccines that have demonstrated significant potential in mice. However, there is a need to develop noninvasive or minimally invasive vaccination methods. In pigs, in vivo gene expression was assessed to compare intradermal needle injection to a needle-free dermal BioJect as a means of delivery of plasmids. Each administration method was further tested with and without surface electroporation. Experiments with plasmid DNA encoding luciferase demonstrated that needle-free administration results in higher gene expression levels than needle injection. Electroporation enhanced gene expression for both intradermal delivery methods. Needle-free plasmid injection in combination with electroporation led to a more rapid induction of immune responses compared to other methods of plasmid administration. It was concluded that needle-free topical electroporation significantly enhances gene expression, possibly by improving cellular uptake of plasmid DNA.