Novel synthesis of superparamagnetic plasmonic core-shell iron oxide-gold nanoparticles

Abstract

Magnetically removable plasmonic nanoparticles are of great interest for biomedical and catalytical applications. A novel and straightforward method to prepare a core-shell structure consisting of a superparamagnetic Fe3O4 core coated with a plasmonic gold shell is described. The synthesis combines ease of functionalization, limited supervision and high reproducibility while being environmentally friendly. A gold shell with a tunable thickness of 30–70 nm was grown on a Fe3O4 core 20 nm in diameter through reduction of gold salt in an ultrasonic bath. The thickness of the gold shell could be tuned by varying the amount of gold salt added. It was possible to prepare core-shell nanoparticles of sizes between 80 and 160 nm. The magnetic and plasmonic behavior of the core-shell nanoparticles is studied. To demonstrate potential use in biomedical applications, a functionalization with polyethylene glycol (PEG) is performed.