Multifunctional gold coated iron oxide core-shell nanoparticles stabilized using thiolated sodium alginate for biomedical applications

•Gold coated iron oxide nanocomposites were synthesized using trisodium citrate.•Synthesized nanocomposites presented aqueous stability upon application of thiolated sodium alginate as stabilizing agent.•Drug loading efficiency for the synthesized nanocomposites was estimated to be around 7.2 wt %.•Reduction in saturation magnetization (Ms) from ~ 41emu/g to ~ 24 emu/g upon coating of polymer and gold on iron oxide nanoparticles.

In this paper we report synthesis of aqueous based gold coated iron oxide nanoparticles to integrate the localized surface plasma resonance (SPR) properties of gold and magnetic properties of iron oxide in a single system. Iron oxide-gold core shell nanoparticles were stabilized by attachment of thiolated sodium alginate to the surface of nanoparticles. Transmission electron microscope (TEM) micrograph presents an average elementary particle size of 8.1 ± 2.1 nm. High resolution TEM (HR-TEM) and X-ray photon spectroscopy further confirms the presence of gold shell around iron oxide core. Gold coating is responsible for reducing saturation magnetization (Ms) value from ~ 41 emu/g to ~ 24 emu/g - in thiolated sodium alginate stabilized gold coated iron oxide core-shell nanoparticles. The drug (curcumin) loading efficiency for the prepared nanocomposites was estimated to be around 7.2 wt% (72 μg drug/mg nanoparticles) with encapsulation efficiency of 72.8%. Gold-coated iron oxide core-shell nanoparticles could be of immense importance in the field of targeted drug delivery along with capability to be used as contrast agent for MRI & CT.