The effects of PEG grafting level and injection dose on gold nanorod biodistribution in the tumor-bearing mice.
Gold nanorods have strong absorbance in the near infrared region, which penetrates deeply into tissues, where the absorbed light energy is converted into heat. Therefore, gold nanorods are expected to act as an effective contrast agent for in vivo bioimaging and as a thermal converter for photothermal therapy. We grafted various amounts of polyethylene glycol (PEG) onto the surface of gold nanorods and investigated the effects of grafting level and injection dose on the biodistribution in the tumor-bearing mice after intravenous injection and enhanced permeability and retention (EPR). Higher PEG grafting levels were advantageous for reticuloendothelial system (RES) avoidance and for suppression of aggregation of the gold nanorods in the circulation. Modification with a PEG:gold molar ratio of 1.5 was sufficient to show both prolonged circulation and the EPR effect. When the injection dose was increased above 19.5 microg of gold, the RES uptake in the liver was saturated and surplus gold nanorods were distributed to other tissues, especially the spleen and the tumor. The results of this study will provide an important basis for the development of cancer therapies mediated by the photothermal effect of gold nanorods.
Akiyama
Yasuyuki
Y
Department of Applied Chemistry, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
Mori
Takeshi
T
Katayama
Yoshiki
Y
Niidome
Takuro
T
D000818:Animals; D045744:Cell Line, Tumor; D006046:Gold / Q000493:pharmacokinetics*; D007275:Injections, Intravenous; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D012157:Mononuclear Phagocyte System / Q000378:metabolism; D043942:Nanotubes; D009368:Neoplasm Transplantation; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D014018:Tissue Distribution
D011092:Polyethylene Glycols; D006046:Gold