Controlled loading of paramagnetic gadolinium oxide nanoplates in PMAO-g-PEG as effective T₁-weighted MRI contrast agents

Plate-shaped Gd2O3nanoclusters (GNCs) with well-controlled loading were fabricated by using amphiphilic poly(maleic anhydride-alt-1-octadecene) (PMAO) grafted with PEG as nanogel. The hydrodynamic size of the obtained GNCs was well controlled to <260 nm under appropriate emulsion process conditions and they showed excellent long-term dispersibility in phosphate buffer saline. MRI measurements clearly indicated the substantial improvement inT1effect of the nanoclusters as compared with the individual Gd2O3nanoplates. The obtained GNCs possessed a highr1value of 7.948 s−1mM−1[Gd], which is 2.23 times higher than that of the commercial product Gd-DOTA, and lowr2/r1of 1.04. In vitro test of the obtained GNCs was demonstrated in NIH/3T3 cell lines, and clearT1-weighted images were obtained. Thus, the PMAO-g-PEG assisted GNCs were potentially useful forT1-weighted MRI contrast agents.