Physico-chemical characteristics, biocompatibility, and MRI applicability of novel monodisperse PEG-modified magnetic Fe3O4&SiO2 core–shell nanoparticles

Abstract

Monodisperse, superparamagnetic oleic acid-stabilized Fe₃O₄ nanoparticles of different sizes were prepared by thermal decomposition of Fe(III) oleate. The particles were subsequently coated by silica shells of different thicknesses (yielding Fe₃O₄&SiO₂) using a water-in-oil (w/o) reverse microemulsion technique and/or were decorated with amino groups by reaction with (3-aminopropyl)triethoxysilane. The resulting Fe₃O₄&SiO₂-NH₂ nanoparticles were then modified with poly(ethylene glycol) (PEG) via reaction with its succinimidyl ester yielding Fe₃O₄&SiO₂-PEG particles. The in vitro biocompatibility and biosafety of the Fe₃O₄&SiO₂ and Fe₃O₄&SiO₂-PEG particles were investigated in a murine neural stem cell model in terms of oxidative stress response and cell viability, proliferation, and uptake. Finally, the potential of both nanoparticle types for application in magnetic resonance imaging (MRI) visualization was evaluated.