title: Simplified synthesis and relaxometry of magnetoferritin for magnetic resonance imaging.
abstract: Magnetoferritin nanoparticles have been developed as high-relaxivity, functional contrast agents for MRI. Several previous techniques have relied on unloading native ferritin and re-incorporation of iron into the core, often resulting in a polydisperse sample. Here, a simplified technique is developed using commercially available horse spleen apoferritin to create monodisperse magnetoferritin. Iron oxide atoms were incorporated into the protein core via a step-wise Fe(II)Chloride addition to the protein solution under low O(2) conditions; subsequent filtration steps allow for separation of completely filled and superparamagnetic magnetoferritin from the partially filled ferritin. This method yields a monodisperse and homogenous solution of spherical particles with magnetic properties that can be used for molecular magnetic resonance imaging. With a transverse per-iron and per-particle relaxivity of 78 mM(-1) sec(-1) and 404,045 mM(-1) sec(-1), respectively, it is possible to detect ∼ 10 nM nanoparticle concentrations in vivo.
authors.affiliation: School of Biological and Health Systems Engineering, Ira A. Fulton School of Engineering, Arizona State University, Tempe, Arizona 85287-9709, USA.
authors.forename: Veronica Clavijo
authors.initials: VC
authors.lastname: Jordan
authors.forename: Michael R
authors.initials: MR
authors.lastname: Caplan
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Bennett
mesh_terms: D000818:Animals; D001052:Apoferritins / Q000138:chemical synthesis*; D001921:Brain / Q000033:anatomy & histology*; D003287:Contrast Media / Q000138:chemical synthesis*; D007501:Iron; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010087:Oxides / Q000138:chemical synthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003287:Contrast Media; D010087:Oxides; C088922:magnetoferritin; D001052:Apoferritins; D007501:Iron