Gene therapy progress and prospects: electroporation and other physical methods.

Over the last 5 years, physical methods of plasmid delivery have revolutionized the efficiency of nonviral gene transfer, in some cases reaching the efficiencies of viral vectors. In vivo electroporation dramatically increases transfection efficiency for a variety of tissues. Other methods with clinical precedent, pressure-perfusion and ultrasound, also improve plasmid gene transfer. Alternatives such as focused laser, magnetic fields and ballistic (gene gun) approaches can also enhance delivery. As plasmid DNA appears to be a safe gene vector system, it seems likely that plasmid with physically enhanced delivery will be used increasingly in clinical trials.