One-step synthesis of magnetic gold nanostars for bioimaging applications

This work presents novel magnetite-gold hybrid nanoparticles formed by multiple magnetic cores inside gold nanostars (SPIO@Au). The nanostructures were produced by one-step hydroxylamine reduction of a gold precursor on the surface of functionalized superparamagnetic iron oxide nanoparticles in an aqueous alkaline medium. The nanoparticles show excellent chemical stability, magnetic properties and an intense surface plasmon resonance in the visible-NIR region. In vitro cellular tests showed that these nanostructures could be efficiently internalized inside A549 cells. The optical properties of the SPIO@Au nanoparticles were exploited for in vitro localization analysis through scattering based imaging. These nanoparticles could have enormous potential for application as contrast agents in combined imaging techniques as well as in bio-analytical applications such as biomolecule and cell separation.