Short noncoding DNA fragment improve efficiencies of in vivo electroporation-mediated gene transfer

Background: A major obstacle to the application of gene therapy methods in experimental and clinical practice is the lack of safe and efficient gene delivery systems. Electroporation has been shown to an effective physical delivery method. A variety of factors have been shown to affect the electroporation-mediated gene delivery efficiency. In the present study, we assessed the usefulness of noncoding short-fragment DNA (sf-DNA) for facilitating electroporation-mediated gene transfer. Methods: The plasmid pGL3-control encoding firefly luciferase was injected into tissues together with or without sf-DNA. Immediately after injection, the tissues were electroporated and the level of luciferase activity was assessed 24h later. Different types of DNA fragments with different molecular weights, structures and doses were compared. The transfection efficiencies of sf-DNA-mediated electroporation in different tissues or with different electric field strengths were examined. Results: Plasmid DNA formulated with 300-bp sf-DNA resulted in a significant improvement in electroporation-mediated gene transfer efficiency. The effect is dose-dependent and is also affected by DNA fragment length and structure. It was useful for intramuscular electroporation application, as well as intratumoral application with various pulse voltage parameters. Conclusions: The data obtained in the present study indicate that sf-DNA can be used as a helper molecule to improve electroporation-mediated gene transfection efficiency.