Facile Preparation of Gold-Decorated Fe3O4 Nanoparticles for CT and MR Dual-Modal Imaging

The development of a multifunctional nanoprobe capable of non-invasive multimodal imaging is crucial for precise tumour diagnosis. Herein, we report a facile polymer-assisted method to produce Au-Fe3O4 nanocomposites (NCPs) for the dual-modal magnetic resonance (MR) and X-ray computed tomography (CT) imaging of tumours. In this approach, amino-functionalized Au nanospheres were first obtained by surface modification of the bifunctional polymer SH-PEG-NH2. Hydrophilic and carboxyl-functionalized Fe3O4 nanoparticles were produced by phase transfer of reverse micelle oxidation in our previous work. The Au nanoparticles were conjugated with hydrophilic Fe3O4 nanoparticles through an amide reaction. The obtained Au-Fe3O4 nanocomposites display a high r(2) relativity (157.92 mM(-1) s(-1)) and a Hounsfield units (HU) value (270 HU) at Au concentration of 8 mg/mL and could be applied as nanoprobes for the dual-modal MR/CT imaging of a xenografted tumour model. Our work provides a facile method to prepare Au-Fe3O4 nanocomposites for dual-modal MR/CT imaging, and this method can be extended to prepare other multifunctional nanoparticles for multimodal bioimaging.