Abstract
Metal nanoparticles (NPs), such as gold NPs (AuNPs), are particularly sensitive to X-rays, and thus specific accumulation of AuNPs in a tumor would allow radiotherapy with low energy X-rays and reduced side effects. AuNPs can be generated using HAuCl4 and the natural polyphenol epigallocatechin-3-gallate (EGCG) in the presence of citrate. Here, we generated EGCG-AuNPs in the presence of several additives and examined the accumulation of these NPs in mouse tumors following intravenous administration. EGCG-AuNPs 15 nm in diameter in the presence of sodium alginate accumulated more in tumors compared to 40-nm-diameter EGCG-AuNPs. Furthermore, the results of in vitro cellular uptake and serum protein absorption studies suggest that adsorption of 15–16 kDa serum proteins to EGCG-AuNPs suppresses accumulation in tumors. Thus, tendency to adsorb specific proteins on EGCG-AuNPs surface should be tailored for enhancing their accumulation in tumors.