Enhanced transfection efficiency in laser-induced stress wave-assisted gene transfer at low laser fluence by increasing pressure impulse

To improve transfection efficiency in gene delivery based on nanosecond pulsed laser-induced stress waves, we examined different types of transparent materials, a poly(ethylene terephthalate) sheet, poly(vinyl alcohol) gel, and water, which were placed on a laser target for plasma confinement. We found that the use of water was most effective for maintaining a large pressure impulse during multipulse laser irradiation and, as a result, high transfection efficiency was demonstrated in rat skin in vivo at a relatively low laser fluence of 0.7 J/cm(2). At this fluence, steady laser transmission through quartz fibers was confirmed, allowing endoscopic application of our gene delivery technique. (C) 2008 The Japan Society of Applied Physics.