Metal Nanostructures with Magnetic and Biodegradable Properties for Medical Applications

Gold nanoparticles (AuNPs) were synthesized by reduction of HAuCl4 with NaBH4 or l-ascorbic acid and they were stabilized with cysteine, cysteamine and a thiol-capped PEG. A nanocomposite was prepared by the addition of polylactic acid (PLA) acetone solutions to aqueous AuNP dispersions, resulting in PLAs enclosing AuNPs. Superparamagnetic iron oxide nanoparticles (SPION) modified with Au on the surface (SPION@Au NP) were synthesized. SPIONs were prepared by using iron-oleate as a precursor or by co-precipitation of ferrous and ferric chlorides in alkaline solution and, then used for seed-mediated growth of gold layers on their surfaces. The various nanoparticles were characterized by using UV-Vis spectroscopy, electron spectroscopy imaging/transmission electron microscopy (ESI/TEM) and by thermogravimetric analysis (TGA). The magnetic products were tested in a magnetic resonance imaging (MRI) scanner of high clinical field with results that indicate their promising utilization as contrast agents for MRI analysis.