Multifunctional Theranostic Graphene Oxide Nanoflakes as MR Imaging Agents with Enhanced Photothermal and Radiosensitizing Properties

The integration of multiple therapeutic and diagnostic functions into a single nanoplatform for image-guided cancer therapy has been an emerging trend in nanomedicine. We show here that multifunctional theranostic nanostructures consisting of superparamagnetic iron oxide (SPIO) and gold nanoparticles (AuNPs) scaffolded within graphene oxide nanoflakes (GO-SPIO-Au NFs) can be used for dual photo/radiotherapy by virtue of the near-infrared (NIR) absorbance of GO for photothermal therapy (PTT) and the Z element radiosensitization of AuNPs for enhanced radiation therapy (RT). At the same time, this nanoplatform can also be detected by magnetic resonance (MR) imaging because of the presence of SPIO NPs. Using a mouse carcinoma model, GO-SPIO-Au NF-mediated combined PTT/RT exhibited a 1.85-fold and 1.44-fold higher therapeutic efficacy compared to either NF-mediated PTT or RT alone, respectively, resulting in a complete eradication of tumors. As a sensitive multifunctional theranostic platform, GO-SPIO-Au NFs appear to be a promising nanomaterial for enhanced cancer imaging and therapy. © 2021 American Chemical Society

Development of Gold-Coated Magnetic Nanoparticles as a Potential MRI Contrast Agent

Gold-coated superparamagnetic iron oxide nanoparticles (SPIONs) coated with methyl-polyethylene glycol (mPEG) are synthesized and investigated as a magnetic resonance (MR) imaging contrast agent. The synthesized mPEG-core@shells are characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), vibrating sample magnetometry (VSM), zeta-potential analysis and X-ray diffraction (XRD). In addition, the transverse relaxivity of the mPEG-core@shells is measured using a 3 T MRI scanner. The cytotoxicity of the mPEG-core@shells is tested in the LNCaP cell line using an 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results show that the mPEG-core@shell particles are semispherical with hydrodynamic size of �65 nm and a transverse relaxivity of 162.3 mM-1 S-1. The mPEG-core@shell particles demonstrate good stability in biological media without any significant in vitro cytotoxicity under high cellular uptake conditions. Finally, in vivo imaging shows that mPEG-core@shells are a potential contrast agent for use in early-stage detection. © 2015 World Scientific Publishing Company