| Summary: | Polyacrylic acid (PAA)-coated lanthanide oxide (Ln<sub>2</sub>O<sub>3</sub>) nanoparticles (NPs) (Ln = Tb and Ho) with high colloidal stability and good biocompatibility were synthesized, characterized, and investigated as a new class of negative (T<sub>2</sub>) magnetic resonance imaging (MRI) contrast agents at high MR fields. Their r<sub>2</sub> values were appreciable at a 3.0 T MR field and higher at a 9.4 T MR field, whereas their r<sub>1</sub> values were negligible at all MR fields, indicating their exclusive induction of T<sub>2</sub> relaxations with negligible induction of T<sub>1</sub> relaxations. Their effectiveness as T<sub>2</sub> MRI contrast agents at high MR fields was confirmed from strong negative contrast enhancements in in vivo T<sub>2</sub> MR images at a 9.4 T MR field after intravenous administration into mice tails.
|
|---|