Structure and dysprosium dopant engineering of gadolinium oxide nanoparticles for enhanced dual-modal magnetic resonance and fluorescence imaging

Abstract

We report a class of multi-functional core–shell nanoarchitectures, consisting of silica nanospheres as the core and Gd₂O₃:Dy³⁺ nanocrystals as the ultra-thin shell, that enable unique multi-color living cell imaging and remarkable in vivo magnetic resonance imaging. These types of targeted cell imaging nanoarchitectures can be used as a variety of fluorescence nanoprobes due to the multi-color emissions of the Gd₂O₃:Dy³⁺ nanophosphor. We also proposed a strategy of modulating core–shell structure design to achieve an enhanced magnetic resonance contrast ability of Gd₂O₃ nanoagents, and the classical Solomon–Bloembergen–Morgan theory was applied to explicate the mechanism underlying the enhancement. The as-synthesized ligand-free nanomaterial possesses a suitable particle size for cellular uptake as well as avoiding penetrating the blood–brain barrier with good water-solubility, stability, dispersibility and uniformity. The extremely low cytotoxicity and favorable biocompatibility obtained from in vitro and in vivo bioassays of the as-designed nanoparticles indicate their excellent potential as a candidate for functioning as a targeted nanoprobe.