Focusing of photomechanical waves with an optical lens for depth-targeted molecular delivery

Takuichirou Shimada, Shunichi Sato, Satoko Kawauchi, Hiroshi Ashida, Mitsuhiro Terakawa

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    2 Citations (Scopus)

    Abstract

    We have been developing molecular delivery systems based on photomechanical waves (PMWs), which are generated by the irradiation of a laser absorbing material with nanosecond laser pulses. This method enables highly site-specific delivery in the horizontal plane of the tissue. However, targeting in the vertical direction is a remaining challenge. In this study, we developed a novel PMW focusing device for deeper tissue targeting. A commercial optical concave lens and black natural rubber sheet (laser absorber) were attached to the top and bottom end of a cylindrical spacer, respectively, which was filled with water. A laser pulse was transmitted through the lens and water and hit the rubber sheet to induce a plasma, generating a PMW. The PMW was propagated both downward and upward. The downward wave (1st wave) was diffused, while the upward (2nd wave) wave was reflected with the concave surface of the lens and focused at a depth determined by the geometrical parameters. To attenuate the 1st wave, a small-diameter silicon sponge rubber disk was adhered just under the rubber sheet concentrically with the laser axis. With the lens of f = -40 mm, the 2nd wave was focused to a diameter of 5.7 mm at a targeted depth of 20 mm, which was well agreed with the result of calculation by ray tracing. At a laser fluence of 5.1 J/cm2, peak pressure of the PMW reached ∼40 MPa at the depth of 20 mm. Under this condition, we examined depth-targeted gene delivery to the rat skin.

    Original languageEnglish
    Title of host publicationOptical Interactions with Tissue and Cells XXV; and Terahertz for Biomedical Applications
    PublisherSPIE
    ISBN (Print)9780819498540
    DOIs
    Publication statusPublished - 2014 Jan 1
    EventOptical Interactions with Tissue and Cells XXV; and Terahertz for Biomedical Applications - San Francisco, CA, United States
    Duration: 2014 Feb 22014 Feb 4

    Publication series

    NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
    Volume8941
    ISSN (Print)1605-7422

    Other

    OtherOptical Interactions with Tissue and Cells XXV; and Terahertz for Biomedical Applications
    CountryUnited States
    CitySan Francisco, CA
    Period14/2/214/2/4

    Keywords

    • Deep tissue
    • Depth targeting
    • Focusing
    • Molecular delivery
    • Nanosecond pulsed laser
    • Photomechanical wave

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Biomaterials
    • Atomic and Molecular Physics, and Optics
    • Radiology Nuclear Medicine and imaging

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  • Cite this

    Shimada, T., Sato, S., Kawauchi, S., Ashida, H., & Terakawa, M. (2014). Focusing of photomechanical waves with an optical lens for depth-targeted molecular delivery. In Optical Interactions with Tissue and Cells XXV; and Terahertz for Biomedical Applications [89410B] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 8941). SPIE. https://doi.org/10.1117/12.2039227