Gold and Gold−Iron Oxide Magnetic Glyconanoparticles:  Synthesis, Characterization and Magnetic Properties

The preparation, characterization and the magnetic properties of gold and gold−iron oxide glyconanoparticles (GNPs) are described. Glyconanoparticles were prepared in a single step procedure in the presence of aqueous solution of thiol functionalized neoglycoconjugates and either gold salts or both gold and iron salts. Neoglycoconjugates of lactose and maltose disaccharides with different linkers were used. Iron-free gold or gold−iron oxide GNPs with controlled gold−iron ratios were obtained. The average core-size diameters are in the range of 1.5−2.5 nm. The GNPs are fully characterized by 1H NMR spectrometry, transmission electron microscopy (TEM), and UV−vis and X-ray absorption (XAS) spectroscopies. Inductive plasma-atomic emission spectrometry (ICP) and elemental analysis gave the average number of neoglycoconjugates per cluster. The magnetic properties were measured in a SQUID magnetometer. The most remarkable results was the observation of a permanent magnetism up to room temperature in the iron-free gold GNPs, that was not present in the corresponding gold−iron oxide GNPs.