Courtesy of Priscilla Furth
Scientists have tried at least four methods for delivering nucleic acids to mammalian tissues for the purpose of inducing exogenous gene expression: scarifying the epithelium with a razor blade, then smearing the skin with DNA; scratching the skin with the back of an 18-gauge needle followed by smearing on of DNA; intradermal inoculation and puncture 200 times with a 27-gauge needle; and interdermal inoculation using a jet injector. The first two techniques didn't work very well, but according to Priscilla Furth, of Georgetown University's Lombardi Cancer Center, the last method does.
When plasmids are propelled through the skin or other tissue by jet injection, DNA is transferred into the cells surrounding the injection path, says Furth, who was recently awarded a US patent (6,730,663) for an improved jet injection method. As of now, the technique is most applicable to DNA immunization, says Furth, but it...