Pharmacokinetics and biodistribution of 2, 6, and 15 nm AuNPs. (a) Blood elimination profiles of Au following a single intravenous injection of Au nanoparticles at a dose of 5 mg Au/kg in tumor-bearing mice. Data represent mean ± SD (n = 3). (b) Au content in tumor, heart, liver, spleen, lung, brain, and kidney 24 h after iv injections of gold nanoparticles at 5 mg Au/kg. Data represent mean ± SD (n = 3) (c) Representative TEM micrographs of tumor tissue taken 24 h after the administration of AuNPs.