Longitudinal Water Proton Relaxivities of Gd(OH)_3 Nanorods, Gd(OH)_3 Nanoparticles, and Gd_2O_3 Nanoparticles: Dependence on Particle Diameter, Composition, and Morphology

Gd(OH)_3 nanorods, Gd(OH)_3 nanoparticles, and Gd_2O_3 nanoparticles were prepared and their longitudinal water proton relaxivities (r_1s) were investigated. They are important for application to a highly sensitive T_1 MRI contrast agent. The r_1s did not much depend on either composition or morphology but on particle diameter such that an optimal particle diameter (∼1.7 nm) exists for a maximal r_1 (~ 15.2 s^(-1)mM^(-1)). This is interpreted such that surface Gd(III) ions mainly contribute to the r_1. KCI Citation Count: 6