Cu-doped Gold Nanoparticles for In-vitro and In-vivo Studies*

Gold Nanoparticles (GNPs) have been utilized as radiosensitizers to amplify radiation's effect on specifically targeted cancerous cells. Since traditional GNPs are not inherently radioactive, it complicates the ability to measure their distribution and clearance from the body following administration to ensure that they are localized to the tumors rather than healthy tissue. In this study, novel GNPs were developed by doping the GNPs with ⁶⁴Cu. These GNPs were then characterized by ultraviolet-visible (UV-Vis) spectroscopy, Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDS), Inductively Coupled Plasma (ICP) emission spectroscopy, and X-ray Photoelectron Spectroscopy (XPS). Additionally, to compare the biocompatibility of ⁶⁴Cu@Au GNPs to that of traditional GNPs, in vitro cytotoxicity studies as well as in vivo biodistribution and pharmacokinetics studies were conducted. After measuring the viability of A-549 cells after exposure to varying concentrations of hybrid GNPs, the IC₅₀ value measured falls within the expected range for traditional GNPs. Further, the hybrid GNPs were administered to mice samples, and the organs and tissues were collected at different time intervals and analyzed for radioactivity levels. The results showed that the organs most responsible for clearing the ⁶⁴Cu@Au GNPs from the blood were the liver, intestines, lungs, and kidneys, with a very low collection of the GNPs in the heart and brain. Furthermore, the pharmacokinetics clearances of the GNPs in these studies aligned with the expected clearance rates for various similarly sized biocompatible nanoparticles. Overall, these preliminary studies suggest that unfunctionalized ⁶⁴Cu@Au GNPs display biological properties and toxicity similar to those of traditional GNPs.