Synthetic routes to magnetic nanoparticles for MPI

Kratz, Harald; Eberbeck, Dietmar; Wagner, Susanne; Taupitz, Matthias; Schnorr, Jörg

doi:10.1515/bmt-2012-0057

Cited by 19 publications

(21 citation statements)

References 80 publications

(117 reference statements)

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“…74 Consequently, multicore particles such as MCP have been developed for MPI and require further investigation of how the MPI signal is affected when MCP cluster in cells. Advantages of combining MRI anatomical information with MPI sensitivity and quantification have been outlined by Kratz et al 75 Therefore, cell labeling for single-cell detection by MRI, as carried out in this study, could make an important contribution to improve cell tracking when combined with MPI.…”

Section: Single-cell Mri In Vitromentioning

confidence: 78%

Labeling of mesenchymal stem cells for MRI with single-cell sensitivity

Schellenberger¹,

Kratz²,

Farr³

et al. 2016

IJN

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Sensitive cell detection by magnetic resonance imaging (MRI) is an important tool for the development of cell therapies. However, clinically approved contrast agents that allow single-cell detection are currently not available. Therefore, we compared very small iron oxide nanoparticles (VSOP) and new multicore carboxymethyl dextran-coated iron oxide nanoparticles (multicore particles, MCP) designed by our department for magnetic particle imaging (MPI) with discontinued Resovist ® regarding their suitability for detection of single mesenchymal stem cells (MSC) by MRI. We achieved an average intracellular nanoparticle (NP) load of >10 pg Fe per cell without the use of transfection agents. NP loading did not lead to significantly different results in proliferation, colony formation, and multilineage in vitro differentiation assays in comparison to controls. MRI allowed single-cell detection using VSOP, MCP, and Resovist ® in conjunction with high-resolution T2*-weighted imaging at 7 T with postprocessing of phase images in agarose cell phantoms and in vivo after delivery of 2,000 NP-labeled MSC into mouse brains via the left carotid artery. With optimized labeling conditions, a detection rate of ~45% was achieved; however, the experiments were limited by nonhomogeneous NP loading of the MSC population. Attempts should be made to achieve better cell separation for homogeneous NP loading and to thus improve NP-uptake-dependent biocompatibility studies and cell detection by MRI and future MPI. Additionally, using a 7 T MR imager equipped with a cryocoil resulted in approximately two times higher detection. In conclusion, we established labeling conditions for new high-relaxivity MCP, VSOP, and Resovist ® for improved MRI of MSC with single-cell sensitivity.

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Section: Single-cell Mri In Vitromentioning

confidence: 78%

Labeling of mesenchymal stem cells for MRI with single-cell sensitivity

Schellenberger¹,

Kratz²,

Farr³

et al. 2016

IJN

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“…MPI can be combined with MRI [ 27 , 28 ] and appears to be particularly well suited for the spatially resolved visualization of rapid dynamic processes in real time such as the beating heart [ 29 – 32 ]. Other applications of MPI may include sentinel lymph node mapping in cancer patients [ 30 , 31 ], passive and active tumor targeting [ 33 ], and stem cell tracking [ 30 , 34 – 36 ]. Resovist ® is a liver-specific MRI contrast agent [ 7 , 37 ], that can be used as MPI Tracer and was taken off the market in Europe in 2008.…”

Section: Introductionmentioning

confidence: 99%

“…Theoretical considerations indicate that single domain MNP with core sizes of about 25–30 nm are best suited for MPI and should be superior to Resovist ® [ 24 , 39 , 40 ]. Therefore, to further exploit the potential of this novel imaging modality, there is a need for improved MPI tracers [ 33 ]. The intensity of the MPI signal is dependent on the magnetic moment of the MNP used as tracers [ 33 , 38 ].…”

Section: Introductionmentioning

confidence: 99%

Novel magnetic multicore nanoparticles designed for MPI and other biomedical applications: From synthesis to first in vivo studies

et al. 2018

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Synthesis of novel magnetic multicore particles (MCP) in the nano range, involves alkaline precipitation of iron(II) chloride in the presence of atmospheric oxygen. This step yields green rust, which is oxidized to obtain magnetic nanoparticles, which probably consist of a magnetite/maghemite mixed-phase. Final growth and annealing at 90°C in the presence of a large excess of carboxymethyl dextran gives MCP very promising magnetic properties for magnetic particle imaging (MPI), an emerging medical imaging modality, and magnetic resonance imaging (MRI). The magnetic nanoparticles are biocompatible and thus potential candidates for future biomedical applications such as cardiovascular imaging, sentinel lymph node mapping in cancer patients, and stem cell tracking. The new MCP that we introduce here have three times higher magnetic particle spectroscopy performance at lower and middle harmonics and five times higher MPS signal strength at higher harmonics compared with Resovist®. In addition, the new MCP have also an improved in vivo MPI performance compared to Resovist®, and we here report the first in vivo MPI investigation of this new generation of magnetic nanoparticles.

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“…Therefore, manufacturing as well as quality assurance of MNPs essentially require comprehensive and accurate analytical methods to measure magnetic and structural properties with regard to application performance and risk assessment. This certainly is a challenging task, especially for broad or multimodal distributions of geometric sizes which often arise from common synthetic routes such as coprecipitation [7,8]. Conventional light scattering (LS) techniques, in particular dynamic LS (DLS) and multi-angle LS (MALS), may give misleading information for polydispersed samples by overestimation of average particle size due to the r 6 dependence of the scattering intensity.…”

Section: Introductionmentioning

confidence: 99%

Hyphenation of Field-Flow Fractionation and Magnetic Particle Spectroscopy

et al. 2015

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Magnetic nanoparticles (MNPs) exhibit unique magnetic properties making them ideally suited for a variety of biomedical applications. Depending on the desired magnetic effect, MNPs must meet special magnetic requirements which are mainly determined by their structural properties (e.g., size distribution). The hyphenation of chromatographic separation techniques with complementary detectors is capable of providing multidimensional information of submicron particles. Although various methods have already been combined for this approach, so far, no detector for the online magnetic analysis was used. Magnetic particle spectroscopy (MPS) has been proven a straightforward technique for specific quantification and characterization of MNPs. It combines high sensitivity with high temporal resolution; both of these are prerequisites for a successful hyphenation with chromatographic separation. We demonstrate the capability of MPS to specifically detect and characterize MNPs under usually applied asymmetric flow field-flow fractionation (A4F) conditions (flow rates, MNP concentration, different MNP types). To this end MPS has been successfully integrated into an A4F multidetector platform including dynamic ligth scattering (DLS), multi-angle light scattering (MALS) and ultraviolet (UV) detection. Our system allows for rapid and comprehensive characterization of typical MNP samples for the systematic investigation of structure-dependent magnetic properties. This has been demonstrated by magnetic analysis of the commercial magnetic resonance imaging (MRI) contrast agent Ferucarbotran (FER) during hydrodynamic A4F fractionation. OPEN ACCESSChromatography 2015, 2 656

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Synthetic routes to magnetic nanoparticles for MPI

Cited by 19 publications

References 80 publications

Labeling of mesenchymal stem cells for MRI with single-cell sensitivity

Labeling of mesenchymal stem cells for MRI with single-cell sensitivity

Novel magnetic multicore nanoparticles designed for MPI and other biomedical applications: From synthesis to first in vivo studies

Hyphenation of Field-Flow Fractionation and Magnetic Particle Spectroscopy

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