Characterization of iron oxide-gold core-shell multifunctional nanoparticles in biomedical imaging

Core-shell iron oxide-gold nanoparticles (Fe₃O₄@Au) can be considered a smart platform for polyvalent presentation on account of their globular shape, tunable size, facile surface chemistry, and biocompatibility. We reported the synthesis and the characterization of Fe₃O₄@Au nanoparticles with transmission electron microscopy (TEM), dynamic light scattering (DLS), ultraviolet visible spectroscopy (UV-Vis), and we investigated their applicability as contrast agents for Magnetic Resonance Imaging (MRI). The measurement of longitudinal and transverse relaxation times of water protons in homogeneous aqueous dispersions of Fe₃O₄@Au nanoparticles with biocompatible coating at different concentrations allowed the assessment of longitudinal (r₁) and transverse (r₂) relaxivities at 1.5 and 3 T. The use of conjugated Fe₃O₄@Au nanoparticles as negative contrast agents could open up new perspectives for the development of novel tools for nanomedicine and for targeted delivery-MRI contrast enhancement systems and photo-optical applications in biomedicine.