Efficiency of Plasmonic Photothermal Therapy of Experimental Tumors

The purpose of this study was to investigate the prognostic factors of plasmonic photothermal therapy (PPT) efficiency in rats with transplanted liver cancer on the basis of assessment of the degree of tumor vascularization. Before any exposure, rats with transplanted liver cancer PC-1 were subjected to Doppler ultrasonography to assess the degree of vascularization of transplanted tumors. Half of the animals with the transplanted tumors were withdrawn from the experiment after Doppler ultrasonography to determine the content of vascular factors in blood serum by enzyme immunoassay and in tumor tissue by immunohistochemical method. After three intravenous injections of polyethylene glycol-coated gold nanorods (GNRs) at a dose of 0.4 mq/mL, the transplanted tumors were irradiated percutaneously with infrared laser radiation at a wavelength of 808 nm, followed by thermography of local tumor heating. The animals were withdrawn from the experiment 24 h later, and tumor tissue samples were taken for histological examination. It is found that the accumulation of gold in the tumor tissue and the PPT efficiency at repeated intravenous GNR injections are determined by the presence of formed vasculature in the tumor.