Synthesis, Characterization, and Therapeutic Efficacy of 177Lu-DMSA@SPIONs in Nanobrachytherapy of Solid Tumors

As an alternative to classical brachytherapy, intratumoral injection of radionuclide-labeled nanoparticles (nanobrachytherapy, NBT) has been investigated as a superior delivery method over intravenous route for radionuclide therapy solid tumors. We created superparamagnetic iron oxide (SPIONs) coated with meso-1,2-dimercaptosuccinic acid (DMSA) and radiolabeled Lutetium-177 (177Lu), generating 177Lu-DMSA@SPIONs potential antitumor agent nanobrachytherapy. Efficient radiolabeling DMSA@SPIONS by 177Lu resulted in stable bond minimal leakage vitro. After mouse colorectal CT-26 or breast 4T1 subcutaneous tumors, the remained well localized at site weeks, limited leakage. The dose 3.70 MBq/100 µg/50 µL applied intratumorally high therapeutic efficacy, without signs general toxicity. A decreased 1.85 still retained while increased 9.25 did not significantly benefit therapy. Histopathology analysis revealed that act within range around site, which explains good efficacy achieved single administration relatively low need repeated dosing. Overall, are safe potent agents suitable intra-tumoral tumor