Progress towards a synthetic virus for systemic gene therapy.

Here we discuss recent progress in non-viral gene therapy with an emphasis on developments which specifically attempt to address the limitations of current systems and their inability to overcome the first barrier to systemic gene delivery, delivery to the disease site and the target cell. Other issues associated with the efficiency of transfection, such as intracellular delivery, the endosomal release of vectors internalized through endocytosis and nuclear delivery are also discussed.