Toxicity and T(2)-Weighted Magnetic Resonance Imaging Potentials of Holmium Oxide Nanoparticles

In recent years, paramagnetic nanoparticles (NPs) have been widely used for magnetic resonance imaging (MRI). This paper reports the fabrication and toxicity evaluation of polyethylene glycol (PEG)-functionalized holmium oxide (Ho(2)O(3)) NPs for potential T(2)-weighted MRI applications. Various characterization techniques were used to examine the morphology, structure and chemical properties of the prepared PEG–Ho(2)O(3) NPs. MRI relaxivity measurements revealed that PEG–Ho(2)O(3) NPs could generate a strong negative contrast in T(2)-weighted MRI. The pilot cytotoxicity experiments showed that the prepared PEG–Ho(2)O(3) NPs are biocompatible at concentrations less than 16 μg/mL. Overall, the prepared PEG–Ho(2)O(3) NPs have potential applications for T(2)-weighted MRI imaging.