Hyaluronic Acid-Functionalized Gadolinium Oxide Nanoparticles for Magnetic Resonance Imaging-Guided Radiotherapy of Tumors

Inaccuracy localization and intrinsic radioresistance of solid tumors seriously hindered the clinical implementation of radiotherapy. In this study, we fabricated hyaluronic acid-functionalized gadolinium oxide nanoparticles (HA-Gd(2)O(3) NPs) via one-pot hydrothermal process for effective magnetic resonance (MR) imaging and radiosensitization of tumors. By virtue of HA functionalization, the as-prepared HA-Gd(2)O(3) NPs with a diameter of 105 nm showed favorable dispersibility in water, low cytotoxicity, and excellent biocompatibility and readily entered into the cytoplasm of cancer cells by HA receptor-mediated endocytosis. Importantly, HA-Gd(2)O(3) NPs exhibited high longitudinal relaxivity (r(1)) 6.0 mM(−1)S(−1) as MRI contrast agents and radiosensitization enhancement in a dose-dependent manner. These finds demonstrated that as-synthesized HA-Gd(2)O(3) NPs as bifunctional theranostic agents have great potential in tumors diagnosis and radiotherapy.