Direct Labeling of Gold Nanoparticles with Iodine-131 for Tumor Radionuclide Therapy

Gold nanoparticles (Au NPs) are widely used as versatile templates to develop multifunctional nanosystems for disease diagnosis and treatment. Iodine can bind to gold via chemisorption, making this a simple method for labeling Au NPs with radioactive iodine. However, the evaluation of tumor radionuclide therapy is insufficient. In this study, we investigated the feasibility of ¹³¹I-adsorbed Au NPs as novel nanoprobes for tumor radionuclide therapy.

Radiolabeling was performed by mixing Au NPs and ¹³¹I, and the radiochemical purity (RCP) and in vitro stability of ¹³¹I-adsorbed Au NPs were analyzed under different conditions, including various temperatures, pH values, and ¹³¹I concentrations. The tumor accumulation and therapeutic potential of ¹³¹I-adsorbed Au NPs were assessed using a subcutaneous tumor model after intratumoral injection.

The data showed that the chemisorption of the Au NPs onto ¹³¹I was instant, specific, and quantitative. The ¹³¹I-adsorbed Au NPs exhibited high in vitro stability in different media, distinct inhibitory effects on tumor cells in vitro, good retention ability, and therapeutic effects after intratumoral injection into tumor-bearing mice in vivo.

Our work demonstrates that chemisorption of Au NPs and radioiodine has great potential as a strategy for constructing various nanosystems for theranostic applications.