BACKGROUND AND OBJECTIVES: Much interest has been shown in the use of lasers for nonviral targeted gene transfer, since the spatial characteristics of laser light are quite well defined. The aim of this study was to demonstrate in vivo gene transfer by the use of laser-induced stress waves (LISWs). STUDY DESIGN/ MATERIALS AND METHODS: After reporter genes had been intradermally injected to rat skin in vivo, a laser target was placed on the gene-injected skin. LISWs were generated by the irradiation of an elastic laser target with 532-nm nanosecond laser pulses of a Q-switched Nd:YAG laser. RESULTS: Levels of luciferase activities for the skin exposed to LISWs were two orders of magnitude higher than those for the skin injected with naked DNA. Expressions of enhanced green fluorescent protein (EGFP) and beta-galactosidase were observed only in the area that was exposed to LISWs, and in addition, epidermal cells were selectively transfected. No major side effects were observed, and luciferase activity levels as high as 10(5) RLU per mg of protein were sustained even 5 days after gene transfer. CONCLUSION: Highly efficient and site-specific gene transfer can be achieved by applying a few pulses of nanosecond pulsed LISWs to rat skin in vivo. Copyright 2004 Wiley-Liss, Inc.
BACKGROUND AND OBJECTIVES: Much interest has been shown in the use of lasers for nonviral targeted gene transfer, since the spatial characteristics of laser light are quite well defined. The aim of this study was to demonstrate in vivo gene transfer by the use of laser-induced stress waves (LISWs). STUDY DESIGN/ MATERIALS AND METHODS: After reporter genes had been intradermally injected to rat skin in vivo, a laser target was placed on the gene-injected skin. LISWs were generated by the irradiation of an elastic laser target with 532-nm nanosecond laser pulses of a Q-switched Nd:YAG laser. RESULTS: Levels of luciferase activities for the skin exposed to LISWs were two orders of magnitude higher than those for the skin injected with naked DNA. Expressions of enhanced green fluorescent protein (EGFP) and beta-galactosidase were observed only in the area that was exposed to LISWs, and in addition, epidermal cells were selectively transfected. No major side effects were observed, and luciferase activity levels as high as 10(5) RLU per mg of protein were sustained even 5 days after gene transfer. CONCLUSION: Highly efficient and site-specific gene transfer can be achieved by applying a few pulses of nanosecond pulsed LISWs to rat skin in vivo. Copyright 2004 Wiley-Liss, Inc.