Iron-based ferritin nanocore as a contrast agent

Abstract

Self-assembling protein cages have been exploited as templates for nanoparticle synthesis. The ferritin molecule, a protein cage present in most living systems, stores excess soluble ferrous iron in the form of an insoluble ferric complex within its cavity. Magnetic nanocores formed by loading excess iron within an engineered ferritin from Archaeoglobus fulgidus (AfFtn-AA) were studied as a potential magnetic resonance (MR) imaging contrast agent. The self-assembly characteristics of the AfFtn-AA were investigated using dynamic light scattering technique and size exclusion chromatography. Homogeneous size distribution of the assembled nanoparticles was observed using transmission electron microscopy. The magnetic properties of iron-loaded AfFtn-AA were studied using vibrating sample magnetometry. Images obtained from a 3.0 T whole-body MRI scanner showed significant brightening of T1 images and signal loss of T2 images with increased concentrations of iron-loaded AfFtn-AA. The analysis of the MR image intensities showed extremely high R2 values (5300 mM−1 s−1) for the iron-loaded AfFtn-AA confirming its potential as a T2 contrast agent.

Large magnonic band gaps and spectra evolution in three-dimensional magnonic crystals based on magnetoferritin nanoparticles

“…For spheres of radius R arranged in an fcc lattice with lattice constant a the filling fraction is ff = 16πR 3 /3a 3 .…”

Radio-Wave Heating of Iron Oxide Nanoparticles Can Regulate Plasma Glucose in Mice

“…An alternative is to engineer cells to synthesize nanoparticles intracellularly. For this purpose, we chose the iron storage protein ferritin, which forms a naturally occurring paramagnetic iron nanoparticle (20, 21) (Fig. 3A and fig.…”

Engineered ferritin nanocages as natural contrast agents in magnetic resonance imaging

“…31 The ferritin nanocages were used as template to load Fe atoms, resulting in formation of magnetic nanostructures (MNS) within their 8 nm core (Scheme 1). By precisely controlling the Fe loading during nanocage formation, 22,31,32 ferritin nanocages with tunable Fe amount were obtained and denoted by (FeX)AfFtnAA where X ¼ 0, 600, 1200, 2400, 3600, and 4800 Fe atoms per cage. We have performed in-depth structural, magnetic, and biocharacterization to understand the mechanism of MNS formation within the core of the protein nanocage and their contribution on water proton relaxation in MRI.…”

“…We have used genetically engineered ferritin from Archaeoglobus fulgidus (AfFtnAA) to produce nanocages that have a slower iron release rate, 31 higher iron loading capacity (up to 7200 Fe atoms per cage), 22 and higher thermal stability (up to 70 C) compared to the wild type of ferritin. 31 The ferritin nanocages were used as template to load Fe atoms, resulting in formation of magnetic nanostructures (MNS) within their 8 nm core (Scheme 1).…”