TY - GEN
T1 - Focusing of photomechanical waves with an optical lens for depth-targeted molecular delivery
AU - Shimada, Takuichirou
AU - Sato, Shunichi
AU - Kawauchi, Satoko
AU - Ashida, Hiroshi
AU - Terakawa, Mitsuhiro
PY - 2014
Y1 - 2014
N2 - 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.
AB - 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.
KW - Deep tissue
KW - Depth targeting
KW - Focusing
KW - Molecular delivery
KW - Nanosecond pulsed laser
KW - Photomechanical wave
UR - http://www.scopus.com/inward/record.url?scp=84901797090&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84901797090&partnerID=8YFLogxK
U2 - 10.1117/12.2039227
DO - 10.1117/12.2039227
M3 - Conference contribution
AN - SCOPUS:84901797090
SN - 9780819498540
T3 - Progress in Biomedical Optics and Imaging - Proceedings of SPIE
BT - Optical Interactions with Tissue and Cells XXV; and Terahertz for Biomedical Applications
PB - SPIE
T2 - Optical Interactions with Tissue and Cells XXV; and Terahertz for Biomedical Applications
Y2 - 2 February 2014 through 4 February 2014
ER -