Assessment of a Heuristic Model for Characterization of Magnetic Nanoparticles as Contrast Agent in MRI

Félix-González, Nazario; Urbano-Bojorge, Ana Lorena; Mina‐Rosales, Alejandra; Guerrero, Francisco del Pozo; Olmedo, José Javier Serrano

doi:10.1002/cmr.a.21361

Cited by 2 publications

(3 citation statements)

References 38 publications

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“…Relaxivity and NMRD profile measurements. The longitudinal relaxivity (r 1 ) of an aqueous fluid containing magnetic material in suspension, generally called CA, is defined as an increase in the longitudinal relaxation rate observed in aqueous solution when the concentration of the magnetically active compound is increased by one millimolar unit [12]. Relaxivities are generally defined by the slope of the linear regression generated from a plot of the measured relaxation rate (1/T) versus the concentration of the CA.…”

Section: Magnetizationmentioning

confidence: 99%

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Influence of medium viscosity and intracellular environment on the magnetization of superparamagnetic nanoparticles in silk fibroin solutions and 3T3 mouse fibroblast cell cultures

et al. 2018

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Biomedical applications based on the magnetic properties of superparamagnetic iron oxide nanoparticles (SPIONs) may be altered by the mechanical attachment or cellular uptake of these nanoparticles. When nanoparticles interact with living cells, they are captured and internalized into intracellular compartments. Consequently, the magnetic behavior of the nanoparticles is modified. In this paper, we investigated the change in the magnetic response of 14 nm magnetic nanoparticles (FeO) in different solutions, both as a stable liquid suspension (one of them mimicking the cellular cytoplasm) and when associated with cells. The field-dependent magnetization curves from inert fluids and cell cultures were determined by using an alternating gradient magnetometer, MicroMagTM 2900. The equipment was adapted to measure liquid samples because it was originally designed only for solids. In order to achieve this goal, custom sample holders were manufactured. Likewise, the nuclear magnetic relaxation dispersion profiles for the inert fluid were also measured by fast field cycling nuclear magnetic relaxation relaxometry. The results show that SPION magnetization in inert fluids was affected by the carrier liquid viscosity and the concentration. In cell cultures, the mechanical attachment or confinement of the SPIONs inside the cells accounted for the change in the dynamic magnetic behavior of the nanoparticles. Nevertheless, the magnetization value in the cell cultures was slightly lower than that of the fluid simulating the viscosity of cytoplasm, suggesting that magnetization loss was not only due to medium viscosity but also to a reduction in the mechanical degrees of freedom of SPIONs rotation and translation inside cells. The findings presented here provide information on the loss of magnetic properties when nanoparticles are suspended in viscous fluids or internalized in cells. This information could be exploited to improve biomedical applications based on magnetic properties such as magnetic hyperthermia, contrast agents and drug delivery.

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Section: Magnetizationmentioning

confidence: 99%

“…Furthermore, their small sizes comparable to cellular organisms (10-100 μm) allow for interactions with subcellular structures. These properties enable the MNPs to be used in applications as contrast agents (CA) [12], in drug delivery [13][14] and in generating magnetic hyperthermia [15][16][17][18][19][20], among others.…”

Section: Introductionmentioning

confidence: 99%

Influence of medium viscosity and intracellular environment on the magnetization of superparamagnetic nanoparticles in silk fibroin solutions and 3T3 mouse fibroblast cell cultures

et al. 2018

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“…NMRD is now used as a characterization method for samples containing SPM NPs. Equation is often used with four fitting parameters (SPM radius, magnetization, Néel time, and P ) to extract the sample properties . The obtained experimental minimal distance of approach is often in the range between the TEM and the hydrodynamic sizes (obtained by dynamic light scattering for example) .…”

Section: Comparison With Experimentsmentioning

confidence: 99%

Magnetic resonance relaxation induced by superparamagnetic particles used as contrast agents in magnetic resonance imaging: a theoretical review

Vuong

Gillis

Roch

et al. 2017

WIREs Nanomed Nanobiotechnol

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Superparamagnetic nanoparticles are used as contrast agents in magnetic resonance imaging and allow, for example, the detection of tumors or the tracking of stem cells in vivo. By producing magnetic inhomogeneities, they influence the nuclear magnetic relaxation times, which results in a darkening, on the image, of the region containing these particles. A great number of studies have been devoted to their magnetic properties, to their synthesis and to their influence on nuclear magnetic relaxation. The theoretical and fundamental understanding of the behavior of these particles is a necessary step in predicting their efficiency as contrast agents, or to be able to experimentally obtain some of their properties from a nuclear magnetic resonance measurement. Many relaxation models have been published, and choosing one of them is not always easy, many parameters and conditions have to be taken into account. Relaxation induced by superparamagnetic particles is generally attributed to an outersphere relaxation mechanism. Each model can only be used under specific conditions (motional averaging regime, static regime, high magnetic field, etc.) or for a particular sequence (Carr-Purcell-Meiboom-Gill, spin echo, free-induction decay, nuclear magnetic relaxation dispersion profile, etc.). The parameters included in the equations must be carefully interpreted. In some more complex conditions, simulations are necessary to be able to predict the relaxation rates. A good agreement is usually observed between the theoretical predictions and the experimental results, although some data still cannot be fully understood, such as the dependence of the transverse relaxation on the magnetic field. WIREs Nanomed Nanobiotechnol 2017, 9:e1468. doi: 10.1002/wnan.1468 For further resources related to this article, please visit the WIREs website.

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Assessment of a Heuristic Model for Characterization of Magnetic Nanoparticles as Contrast Agent in MRI

Cited by 2 publications

References 38 publications

Influence of medium viscosity and intracellular environment on the magnetization of superparamagnetic nanoparticles in silk fibroin solutions and 3T3 mouse fibroblast cell cultures

Influence of medium viscosity and intracellular environment on the magnetization of superparamagnetic nanoparticles in silk fibroin solutions and 3T3 mouse fibroblast cell cultures

Magnetic resonance relaxation induced by superparamagnetic particles used as contrast agents in magnetic resonance imaging: a theoretical review

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