Rapid synthesis of 125I integrated gold nanoparticles for use in combined neoplasm imaging and targeted radionuclide therapy

Abstract

The selective delivery of radionuclides to tissues of interest remains a problematic task during treatment. The lack of tissue specificity for many therapeutics limit their efficacy by putting healthy organs and tissues at risk (e.g., side effects). Therefore, high specificity therapeutic strategies are needed to overcome these risks. The objective of this study was to use a modified citrate reduction technique to synthesize gold nanoparticles (AuNPs) containing ¹²⁵I in order to combine their unique therapeutic and diagnostic properties. This task was accomplished by varying the insertion time of ¹²⁵I, which will cause complete aggregation if added too early in the AuNP synthesis process. Even though ¹²⁵I was utilized in this experiment, studies are underway to see if this approach can be extrapolated to shorter-lived isotopes (e.g., ²¹¹At). Characterization of the ¹²⁵I-AuNPs was carried out using UV-Vis spectrometry and Transmission Electron Microscopy (TEM). The appropriate addition time of ¹²⁵I was determined to be approximately 50s after the addition of sodium citrate. TEM measured the nanoparticles' diameters to be in the 10-20nm range. The AuNPs were found to be extremely stable, with no observable leaching of radioactivity into the solution. ¹²⁵I-AuNPs could be beneficial as a contrast agent in CT imaging and therapy since AuNPs enhance the bio-delivery of ¹²⁵I to neoplasms.