In Situe Synthesis of Iron Oxide within Polyvinylamine nanoparticles

Abstract

Magnetic nanoparticles that display high saturation magnetization and high magnetic susceptibility with a size less than 200 nm are of great interest for medical applications. Investigations of magnetic nanoparticles have been increasing over the last decade. Magnetite nanoparticles are particularly desirable since the biocompatibility of these particles has already been proven. Several synthetic and natural polymers have been employed to stabilize magnetite nanoparticles and enhance their function in vivo. The goal of this work has been to develop a unique methodology for synthesizing magnetite within polymer nanoparticle dispersions so that the resultant magnetite-polymer particles may be used in a range of biomedical applications, specifically as an MRI contrast agent. A method was developed for preparing ≈150 nm polyvinylamine (PVAm) nanoparticles containing iron oxide. These polymeric nanoparticles offer colloidal stability and reactive primary amines for drug conjugation or surface modification. The polymer-magnetite nanoparticles described in this thesis exhibited a maximum of 12% wt. magnetite and a saturation magnetization of ~30 emu/mg. Transmission electron microscopy (TEM) images showed that the dispersions contained ≈100 to 150 nm diameter PVAm nanoparticles incorporated with iron oxide particles with a size less than ≈10 nm. The ability to synthesize iron oxide inside functionalized polymeric nanoparticles offers an effective approach to prevent nanoparticle agglomeration and the potential to enable ligand grafting. Stabilized magnetic PVAm nanoparticles may provide a unique synthetic approach to enhance MRI contrast and may offer a platform for molecular imaging.