Plasmonic Photothermal Therapy of Transplanted Tumors in Rats at Multiple Intravenous Injection of Gold Nanorods

The aim of this study was to evaluate the morphological changes in tumor tissue in rats with transplanted liver cancer PC-1 after repeated intravenous (IV) administration of gold nanorods (GNRs) and plasmonic photothermal therapy (PPT). GNRs with aspect ratio 4.1 and plasmonic peak at 810 nm were functionalized with thiolated polyethylene glycol and IV administered at a single dose 0.4 mg of Au and by repeated injection of the same dose for 2 and 3 days (the total doses were 0.8 and 1.2 mg of Au, respectively). One day after the last IV injection of GNRs, the tumors were irradiated by an 808-nm NIR diode laser at a power density 2.3 W/cm 2 during 15 min. The withdrawal of the animals from the experiment and sampling of the tissues for morphological study and GNR distribution were performed 24 h after the PPT. Repeated IV administration of GNRs in tumor-bearing rats resulted in the highest accumulation of nanoparticles in both liver and spleen tissues. After triplicate IV injection of GNRs, they accumulated in the tumor and related PPT effects were comparable with those observed after direct intratumoral injection of the single GNR dose.