Laser-induced rupture of infrared dye-doped liposomes

Near-infrared dyes can be used as a highly localized heat source in nanostructures. Laser irradiation to dye-doped liposomes causes giant temperature- and pressure-jumps at the lipid bilayer, resulting in the rupture of liposomes. This laser-induced process is promising in medical applications such as drug delivery and photodynamic therapy. Photoacoustic generation of a spherical pressure wave in microscopic domains also suggests the possibility of micro- or nano-implosion, which may offer a powerful mechanism for spontaneous focusing of photoacoustic energy in solution. In this chapter, we discuss laser-induced dynamics in liposome solutions studied by fiuorometry and time-resolved phase-contrast microscopy. Microscopic snapshots suggest very fast and spherically symmetric rupturing dynamics that is consistent with Mie theoretical calculations and photoacoustic simulations.