Gold Nanoshells Coated 5-Aminolevulinic Liposomes for Photothermal-Photodynamic Antitumor Therapy

In this study, a novel antitumor system was designed on the basis of photodynamic therapy and photothermal therapy using gold nanoshells coated 5-aminolevulinic acid (5-ALA) liposomes (GNALs). As a widely used photosensitizer prodrug, 5-aminolevulinic acid (5-ALA)-derived protoporphyrin IX (PpIX) can accumulate to a higher level in tumors than in normal tissues. Protoporphyrin IX (PpIX) initiates a series of cytotoxic reactions after irradiation of target tissue with a measured dose of light with appropriate wavelength, which may be dependent on the generation of reactive oxygen species. Gold nanoshells can strongly absorb NIR lasers at the same time, and can generate hyperthermia to provide photothermic effects. Gold nanoshells coated 5-ALA-Liposomes (GNALs) exhibit a uniform-sized spherical shape of 185.8±0.91 nm, with a zeta potential of 33±1.6 mV. Liposomes with specific sizes ranging from 100 to 200 nm can escape into the tumor interstitial tissue and accumulate preferentially in tumor tissue owing to the EPR effect. In addition, NIR light-excited nanosystems significantly promoted antitumor effects in this study compared to single photodynamic therapy. It was also found that the increased temperature promoted inhibition rate of SKOV3 cells. The novel drug delivery system shows great potential in photothermal-photodynamic antitumor therapy.