Synthesis and investigation of magnetite-gold hybrid nanoparticles for visualization and targeted delivery purposes

During last decades magnetite and gold nanoparticles (NPs) attract a deep interest of scientists due to their potential application in therapy and diagnostics. Fe3O4 NPs have the ability to enhance T2-contrast in magnetic... [ view full abstract ]

During last decades magnetite and gold nanoparticles (NPs) attract a deep interest of scientists due to their potential application in therapy and diagnostics. Fe₃O₄ NPs have the ability to enhance T2-contrast in magnetic resonance imaging (MRI) and deliver drugs using an external magnetic field. Au NPs are characterized by high stability, biocompatibility, and can be covalently functionalized by a wide spectrum of thiol-containing ligands. The idea of Fe₃O₄-Au hybrid material creation is the combination of magnetite and gold promising properties as well as the presence of two types of surfaces.

Hybrid magnetite-gold NPs were obtained by the decomposition of iron pentacarbonyl on the surface of gold NPs. As a result, so-called dumbbell-like structures were obtained where magnetite with spherical (sample D-1, 13±2 nm) or cubic (sample D-2, 23±2 nm) shape and spherical gold NPs were connected together pairwise.

The samples were transferred into water by means of block-copolymer Pluronic F127. R2-relaxivity rates at the level of 167 and 385 mM^-1s^-1 were obtained for samples D-1 and D-2, respectively; the latter value is a record value for hybrid Fe₃O₄-Au NPs, exceeding the similar characteristics of commercial contrast agents twice. 

The sample D-1 was also used for the selective functionalization of Fe₃O₄ NPs surface with anti-cancer drug doxorubicin and Au NPs surface – with the ligand of prostate specific membrane antigen (PSMA). Obtained NPs were found to have dose-related toxicity for human prostate cancer cells (LNCaP cell line) and got into the intracellular space after 45 minutes of incubation (according to fluorescence microscopy data). This can be explained by the affinity of the LNCaP cells to the PSMA ligand.

Thereby, in this work magnetite-gold hybrid NPs, which have a strong potential for biomedical application, particularly in targeted drug delivery to liver and prostate cells, and magnetic resonance imaging, were synthesized and characterized. That paves the way to the development of a new theranostic approach.

The authors gratefully acknowledge the financial support of the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST «MISiS» (№K2-2016-069).