Heating efficiency of magnetic nanoparticles decreases with gradual immobilization in hydrogels

Engelmann, U.; Seifert, Julian; Mues, Benedikt; Roitsch, Stefan; Ménager, Christine; Schmidt, Annette; Slabu, Ioana

doi:10.1016/j.jmmm.2018.09.113

Cited by 36 publications

(30 citation statements)

References 41 publications

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“…It produced 3.3 and 5.5 times more contrast in T 2 -weighted imaging than Resovist ® (130 mM −1 s −1 ) and Sinerem ® (79 mM −1 s −1 ), respectively. A number of studies have demonstrated that the core size, the size distribution and the magnetization of SPION are key factors influencing the transverse relaxation rate (1/T 2 ) [15,30]. The trend for the r 1 values for the samples C1-C5 was found to be similar to that observed for the r 2 values.…”

Section: Magnetic Resonance Imagingsupporting

confidence: 53%

“…This leads to partial blocking of the above-mentioned Brownian relaxation and to a drop in heating efficiency. In consequence, depending on the mechanism responsible for heat generation for a specific nanoparticle type, the in vivo hyperthermia performance could significantly decrease [30]. Figure 6a depicts the time-temperature curves for the monodisperse SPION batches C1-C5, as well as for the crude sample C, Resovist ® and Sinerem ® in a lowfrequency AMF.…”

Section: Magnetic Fluid Hyperthermiamentioning

confidence: 99%

See 1 more Smart Citation

Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance

Dadfar¹,

Camozzi²,

Darguzyte³

et al. 2020

J Nanobiotechnol

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145

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Superparamagnetic iron oxide nanoparticles (SPION) are extensively used for magnetic resonance imaging (MRI) and magnetic particle imaging (MPI), as well as for magnetic fluid hyperthermia (MFH). We here describe a sequential centrifugation protocol to obtain SPION with well-defined sizes from a polydisperse SPION starting formulation, synthesized using the routinely employed co-precipitation technique. Transmission electron microscopy, dynamic light scattering and nanoparticle tracking analyses show that the SPION fractions obtained upon size-isolation are well-defined and almost monodisperse. MRI, MPI and MFH analyses demonstrate improved imaging and hyperthermia performance for size-isolated SPION as compared to the polydisperse starting mixture, as well as to commercial and clinically used iron oxide nanoparticle formulations, such as Resovist ® and Sinerem ®. The size-isolation protocol presented here may help to identify SPION with optimal properties for diagnostic, therapeutic and theranostic applications.

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Section: Magnetic Resonance Imagingsupporting

confidence: 53%

Section: Magnetic Fluid Hyperthermiamentioning

confidence: 99%

Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance

Dadfar¹,

Camozzi²,

Darguzyte³

et al. 2020

J Nanobiotechnol

Self Cite

145

View full text Add to dashboard Cite

show abstract

“…The above conclusions correspond well with the other works on magnetic heating efficiency in hydrogels. Engelmann et al [26] recently indicated that the macroscopic structure of the gel, in which magnetic nanoparticles are embedded (mesh size), can hinder Brown relaxation for sufficiently large magnetic objects. This effect is not the only one that explains the lower efficiency of magnetic hyperthermia for cluster nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Tissue-Mimicking Phantom Compressibility on Magnetic Hyperthermia

et al. 2019

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During hyperthermia, magnetite nanoparticles placed in an AC magnetic field become a source of heat. It has been shown that in fluid suspensions, magnetic particles move freely and generate heat easily. However, in tissues of different mechanical properties, nanoparticle movement is limited and leads to a small temperature rise in tissue. Therefore, it is crucial to conduct magnetic hyperthermia experiments in similar conditions to the human body. The effect of tissue-mimicking phantom compressibility on the effectiveness of magnetic hyperthermia was investigated on agar phantoms. Single and cluster nanoparticles were synthesized and used as magnetic materials. The prepared magnetic materials were characterized by transmission electron microscopy (TEM), and zeta potential measurements. Results show that tissue-mimicking phantom compressibility decreases with the concentration of agar. Moreover, the lower the compressibility, the lower the thermal effect of magnetic hyperthermia. Specific absorption rate (SAR) values also proved our assumption that tissue-mimicking phantom compressibility affects magnetic losses in the alternating magnetic field (AMF).

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“…It is also worth noting that the calculated SAR values shown in Figs. 1 , 4 and 5 were obtained in this work by numerically integrating low frequency hysteresis loops of assemblies of superparamagnetic nanoparticles according to the well-known 40 , 52 , 53 thermodynamic formula, , without invoking any additional hypotheses about the dynamic magnetic susceptibility of the assembly 27 , or the relaxation times of nanoparticles 30 , 54 . Low-frequency hysteresis loops, examples of which are shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

Properties of assembly of superparamagnetic nanoparticles in viscous liquid

Usov

Rytov

Bautin

2021

Sci Rep

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Detailed calculations of the specific absorption rate (SAR) of a dilute assembly of iron oxide nanoparticles with effective uniaxial anisotropy dispersed in a liquid are performed depending on the particle diameters, the alternating (ac) magnetic field amplitude H0 and the liquid viscosity. For small and moderate H0 values with respect to particle anisotropy field Hk the SAR of the assembly as a function of the particle diameter passes through a characteristic maximum and then reaches a plateau, whereas for sufficiently large amplitudes, H0 ~ Hk, the SAR increases monotonically as a function of diameter. The realization of viscous and magnetic oscillation modes for particle unit magnetization vector and director for moderate and sufficiently large H0 values, respectively, explains this behavior. It is found that the SAR of the assembly changes inversely with the viscosity only in a viscous mode, for nanoparticles of sufficiently large diameters. In the magnetic mode the SAR of the assembly is practically independent of the viscosity, since in this case the nanoparticle director only weakly oscillates around the ac magnetic field direction. The conditions for the validity of the linear response theory have been clarified by comparison with the numerical simulation data.

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Heating efficiency of magnetic nanoparticles decreases with gradual immobilization in hydrogels

Cited by 36 publications

References 41 publications

Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance

Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance

The Effect of Tissue-Mimicking Phantom Compressibility on Magnetic Hyperthermia

Properties of assembly of superparamagnetic nanoparticles in viscous liquid

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