Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5361683 | Applied Surface Science | 2009 | 4 Pages |
Abstract
Propagation characteristics of laser-induced stress waves (LISWs) in tissue and their correlation with properties of gene transfection were investigated for targeted deep-tissue gene therapy. LISWs were generated by irradiating a laser-absorbing material with 532-nm Q-switched Nd:YAG laser pulses; a transparent plastic sheet was attached on the absorbing material for plasma confinement. Temporal pressure profiles of LISWs that were propagated through different thickness tissues were measured with a needle-type hydrophone and propagation of LISWs in water was visualized by shadowgraph technique. The measurements showed that at a laser fluence of 1.2Â J/cm2 with a laser spot diameter of 3Â mm, flat wavefront was maintained for up to 5Â mm in depth and peak pressure P decreased with increasing tissue thickness d; P was proportional to dâ0.54. Rat dorsal skin was injected with plasmid DNA coding for reporter gene, on which different numbers of excised skin(s) was/were placed, and LISWs were applied from the top of the skins. Efficient gene expression was observed in the skin under the 3Â mm thick stacked skins, suggesting that deep-located tissue such as muscle can be transfected by transcutaneous application of LISWs.
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Authors
Takahiro Ando, Shunichi Sato, Shinta Takano, Hiroshi Ashida, Minoru Obara,