Preparation of monodisperse functionalised superparamagnetic nanoparticles

Monocrystalline iron oxide nanoparticles were synthesised by a one-pot procedure using iron salts in benzyl alcohol and functionalised with dopamine and carboxylmethylated dextran. Dextran macromolecules with low and high carboxyl contents were synthesised and grafted onto the dopamine-functionalised nanoparticles. The particles were characterised using X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), transmission electron microscopy (TEM) and dynamic light scattering (DLS). Monodisperse functionalised nanoparticles were obtained with a hydrodynamic diameter of 20-50 nm. The functionalisation also provided excellent colloidal stability in phosphate buffered saline, even at high salt concentration.