One-Pot Synthesis of Water-Soluble and Biocompatible Superparamagnetic Gadolinium-doped Iron Oxide Nanoclusters
The synthesis of superparamagnetic nanoclusters is critical for ultra-sensitive magnetic resonance imaging (MRI). Herein, we describe the synthesis of water-soluble, biocompatible and superparamagnetic gadolinium-doped iron oxide nanoclusters (GdIO NCs) via a one-pot reaction by thermal decomposition ferric oleate and gadolinium oleate precursors with α,ω-dicarboxyl poly(ethylene glycol) as a surfactant. The resulting water-dispersible GdIO NCs nanoclusters possess good stability, monodispersity with narrow size distribution and exhibit superparamagnetic behaviors. We also explored the effect of gadolinium doping amounts on the the magnetic properties and longitudinal (r1) and transverse relaxivity (r2) of nanoclusters. In addition, the GdIO NCs can be functionalized with fluorescein isothiocyanate (FITC) while maintaining magnetic and biocompatibility. The GdIO NCs and FITC conjugated NCs were preliminary evaluated as MRI and fluorescent probes. The results show the GdIO NCs provides an important nano-platform for theranostic with non-invasive MRI and optical monitoring capability.