Magnetoferritin: Characterization of a novel superparamagnetic MR contrast agent

Bulte, Jeff W.M.; Douglas, Trevor; Mann, Stephen; Frankel, Richard B.; Moskowitz, Bruce M.; Brooks, Rodney A.; Baumgarner, Charles D.; Vymazal, Josef; Strub, Marie‐Paule; Frank, Joseph A.

doi:10.1002/jmri.1880040343

Cited by 162 publications

(114 citation statements)

References 32 publications

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“…It has been reported that the relaxivity greatly depends on the strength of the magnetic field used (Gossuin et al 2010). The r 2 /r 1 value obtained for the ascorbic acid coated iron oxide nanoparticles of size 5 nm is in agreement with that reported by Bulte et al (1994), for protein encapsulated magnetic core of size 7 nm.…”

Section: Resultssupporting

confidence: 89%

Water-dispersible ascorbic-acid-coated magnetite nanoparticles for contrast enhancement in MRI

2014

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Superparamagnetic iron oxide nanoparticles of size *5 nm surface functionalized with ascorbic acid (vitamin C) form a stable dispersion in water with a hydrodynamic size of *30 nm. The anti-oxidant property of ascorbic acid is retained after capping, as evidenced from the capability of converting methylene blue to its reduced leuco form. NMR relaxivity studies show that the ascorbic-acid-coated superparamagnetic iron oxide aqueous nanofluid is suitable as a contrast enhancement agent for MRI applications, coupled with the excellent biocompatibility and medicinal values of ascorbic acid.

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Section: Resultssupporting

confidence: 89%

Water-dispersible ascorbic-acid-coated magnetite nanoparticles for contrast enhancement in MRI

2014

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“…Magnetoferritin was prepared as previously described [Meldrum et al, 1992;Bulte et aL, 1994]. Repeated increments of 115 Fe(II) ions per protein molecule, followed by stoichiometric amounts of oxidant, were added to the synthesis mixture to give a theoretical final loading of 2300 Fe atoms in each protein cavity.…”

Section: Experimental Methodsmentioning

confidence: 99%

Determination of the preexponential frequency factor for superparamagnetic maghemite particles in magnetoferritin

Moskowitz¹,

Frankel

Walton

et al. 1997

J. Geophys. Res.

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Abstract. Magnetization and M0ssbauer measurements on maghemite particles with an average particle diameter of 10 nm have been made in the temperature range from 5 K to 353 K spanning the superparamagnetic (SPM) and stable single domain (SD) regimes. The maghemite particles were produced within the iron-storage protein ferdtin, resulting in a narrowly-sized, weakly interacting nanocomposite material called magnetoferritin. Experiments combining hysteresis measurements, low temperature remanence, and MOssbauer spectroscopy were used to characterize magnetoferritin and to provide experimental estimates of (1) the pre-exponential frequency factor fo in the NOel-Arhennius relaxation equation; (2) the SPM threshold size at room temperature for maghemite; and (3) the SD value of H•/H• at 0 K. The frequency factor was determined from the difference in blocking temperatures measured by dc magnetization and M0ssbauer spectroscopy, yielding a value of f0=109 Hz. This agrees well with the standard value and justifies the usually assumed superparamagnetic blocking condition of KV=25 kT for remanence measurements. The SPM threshold size at room temperature for remanence measurements was estimated to be 20-27 nm and the extrapolated SD value at 0 K for H•/H c is 1.32. The latter value is slightly larger than the theoretical value of 1.09 but may be more appropriate for weakly interacting SD particles commonly found in sediments and soils. However, fo for ferrimagnetic magnetoferritin is a factor of 103 lower than was determined previously for native ferritin, which contains antiferromagnetic ferrihydrite cores. The difference in fo values between the two varieties of ferritin is probably related to the two different types of magnetic spin ordering of the core minerals and suggests that the higher value off0 is more appropriate for antiferromagnetic minerals like hematite and goethite, whereas the lower value is more appropriate for ferrimagnefic minerals like maghemite, magnetite, or greigite.

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“…14 In other words, ferritin is only partly superparamagnetic, and the native ferritin protein is therefore a rather weak T 2 contrast agent. Replacing its native iron core with a synthetic paramagnetic core has proven to result in effective T 2 contrast agents both in vitro 40,41 and in vivo. 42 More sensitive detection methods using phase images for generating hyperintense (bright) contrast might improve the detection of specific FerrH contrast generation, as was proposed recently by Mills and Ahrens.…”

Section: Evaluation Of Ferritin As Mri Reporter Gene G Vande Velde Et Almentioning

confidence: 99%

Evaluation of the specificity and sensitivity of ferritin as an MRI reporter gene in the mouse brain using lentiviral and adeno-associated viral vectors

et al. 2011

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The development of in vivo imaging protocols to reliably track transplanted cells or to report on gene expression is critical for treatment monitoring in (pre)clinical cell and gene therapy protocols. Therefore, we evaluated the potential of lentiviral vectors (LVs) and adeno-associated viral vectors (AAVs) to express the magnetic resonance imaging (MRI) reporter gene ferritin in the rodent brain. First, we compared the induction of background MRI contrast for both vector systems in immune-deficient and immune-competent mice. LV injection resulted in hypointense (that is, dark) changes of T 2 /T 2 * (spin-spin relaxation time)-weighted MRI contrast at the injection site, which can be partially explained by an inflammatory response against the vector injection. In contrast to LVs, AAV injection resulted in reduced background contrast. Moreover, AAV-mediated ferritin overexpression resulted in significantly enhanced contrast to background on T 2 *-weighted MRI. Although sensitivity associated with the ferritin reporter remains modest, AAVs seem to be the most promising vector system for in vivo MRI reporter gene imaging. Gene Therapy (2011) INTRODUCTIONThe development of non-invasive imaging methods that can reliably report on therapeutic cell transplantation and/or gene expression is a critical step in the establishment of gene therapy protocols, both for clinical and for research applications. Several molecular imaging modalities are available that enable non-invasive and repeated imaging of gene expression in targeted cells in living organisms, thereby reducing the number of laboratory animals and reducing the inter-animal variability at the preclinical level. Among these are radionuclide imaging techniques such as single-photon emission computed tomography (SPECT) and positron emission tomography (PET), optical imaging methods including fluorescence imaging and bioluminescence imaging (BLI), magnetic resonance imaging (MRI) and spectroscopy, ultrasound and X-ray-based methods (for a review, see the studies by Massoud and Gambhir 1 and Deroose et al. 2 ). Apart from optical imaging methods, molecular imaging technologies using these imaging modalities have the advantage of being translatable to a clinical setting.When comparing imaging modalities, BLI, PET and SPECT provide high sensitivity but low resolution, whereas MRI can reach near-cellular resolution, 3-6 which makes MRI ideally suited to provide information on the location and migration of targeted cells in vivo.

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Magnetoferritin: Characterization of a novel superparamagnetic MR contrast agent

Cited by 162 publications

References 32 publications

Water-dispersible ascorbic-acid-coated magnetite nanoparticles for contrast enhancement in MRI

Water-dispersible ascorbic-acid-coated magnetite nanoparticles for contrast enhancement in MRI

Determination of the preexponential frequency factor for superparamagnetic maghemite particles in magnetoferritin

Evaluation of the specificity and sensitivity of ferritin as an MRI reporter gene in the mouse brain using lentiviral and adeno-associated viral vectors

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