A Robust Scaffold for Multimodality Using a Plasmonic Gold Core and a Mesoporous Iron Oxide Shell

Introduction: Multifunctional nano-systems provide an alluring approach towards designing nanoparticles with desired characteristics, which emerge from the interaction between various components of the system. A combination of... [ view full abstract ]

Introduction: Multifunctional nano-systems provide an alluring approach towards designing nanoparticles with desired characteristics, which emerge from the interaction between various components of the system. A combination of various imaging modalities augments the advantages and simultaneously overcomes the restrictions encountered by the individual technique. Nano-particles providing combined Magnetic resonance (MR) imaging and X-ray computed tomography (CT) are very promising. CT and MR image acquisition and registration are the foremost steps in radiation therapy planning. These provide valuable information in target definition and determination of radiation dosage. This report describes a simple one-pot approach for the development of multifunctional gold core/iron oxide porous shell nanoparticles (AuFe NPs) functionalized with matrix metalloproteinase (MMP) peptide for targeted multi-mode magnetic resonance (MR) imaging and computed tomography (CT) imaging of human gastric cancer cells (SNU-484 cells). The drug loading capacity of the porous iron oxide nanoshell was also demonstrated.
Methods: We devise a modified one-pot solvothermal reaction to synthesize AuFe core-shell nanoparticles. Here, the Au seeds are first formed in the same reaction mixture, prior to iron oxide formation due to the lower reduction potential of gold compared to iron. By carefully controlling the reaction conditions, uniform AuFe core-shell particles were generated with a spherical Au core and mesoporous Fe3O4 shell. The particles are loaded with Doxorubicin (Dox) and the surface is protected with polyethylene glycol and coated with MT1-MMP peptide for targeting.
Results: The as-obtained nanoparticles demonstrate excellent colloidal stability and biocompatibility. The gold core provides a strong X-ray absorption and the Fe3O4 shell enables the MR imaging and MMP peptide provides successful targeting. AuFe NPs were successfully loaded with Dox and a surface quenching effect of the gold nanoparticles is proposed and correlated with the release of Dox from the porous core/shell system.
Discussion: The AuFe NPs successfully demonstrate a multifunctional platform for MR/CT dual imaging of gastric cancer cells in vitro. Also, the porous nanoshell can be loaded with an appropriate drug of choice for future applications in theragnosis. Morphological, magnetic, CT and cell experiments demonstrate the AuFe nanoparticles as possible candidates for advanced medical purposes.