Standardisation of magnetic nanoparticles in liquid suspension

Wells, James; Kazakova, Olga; Posth, Oliver; Steinhoff, Uwe; Petronis, Šarūnas; Bogart, Lara K.; Southern, Paul; Pankhurst, Quentin A.; Johansson, Christer

doi:10.1088/1361-6463/aa7fa5

Cited by 59 publications

(43 citation statements)

References 156 publications

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“…The multicore superparamagnetic state has a comparable magnetic structure with multicore magnetic particles (MCP)that have been shown to be promising for a wide range of biomedical applications, in particular in magnetic hyperthermia treatment and magnetic resonance imaging [74,75]. So, we can conclude that control of crystallite size in the synthesis of manganites allows a controlled change of magnetism in these compounds.…”

Section: Superparamagnetic Crystallite With Multicorementioning

confidence: 99%

Synthesis and ESR Study of Transition from Ferromagnetism to Superparamagnetism in La_0.8Sr_0.2MnO₃ Nanomanganite

Yahya¹,

Hosni²,

Hamzaoui³

2020

Smart Nanosystems for Biomedicine, Optoelectronics and Catalysis

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Electron spin resonance (ESR) spectroscopy was used to determine the magnetic state transitions of nanocrystalline La 0.8 Sr 0.2 MnO 3 at room temperature, as a function of crystallite size. Ferromagnetic nanoparticles having an average crystallite size ranging from 9 to 57 nm are prepared by adopting the autocombustion method with two-step synthesis process. Significant changes of the ESR spectra parameters, such as the line shape, resonance field (Hr), g-factor, linewidth (∆Hpp), and the low-field microwave absorption (LFMA) signal, are indicative of the change in magnetic domain structures from superparamagnetism to single-domain and multi-domain ferromagnetism by increase in the crystallite size. Samples with crystallite sizes less than 24.5 nm are in a superparamagnetic state. Between 24.5 and 32 nm, they are formed by a single-domain ferromagnetic. The multi-domain state arises for higher sizes. In superparamagnetic region, the value of g-factor is practically constant suggesting that the magnetic core size is invariant with decreasing crystallite size. This contradictory observation with the core-shell model was explained by the phenomenon of phase separation that leads to the formation of a new magnetic state that we called multicore superparamagnetic state.

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Section: Superparamagnetic Crystallite With Multicorementioning

confidence: 99%

Synthesis and ESR Study of Transition from Ferromagnetism to Superparamagnetism in La_0.8Sr_0.2MnO₃ Nanomanganite

Yahya¹,

Hosni²,

Hamzaoui³

2020

Smart Nanosystems for Biomedicine, Optoelectronics and Catalysis

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“…97) and the standardization has been described by Wells et al in 2017. 98 Fig . 2D shows the architecture of a multi-core MP that is typically used in lab-on-chip applications.…”

Section: Magnetic Cores and Magnetic Particlesmentioning

confidence: 99%

“…This implies that the magnetic moment of the MP is zero in absence of an external field. For the small field regime (B typically <50 mT) the magnetization is approximately linear with the external field and occurs on a timescale that is short 98 (1) magnetic cores in brown, (2) core aggregate, (3) non-magnetic shell in gray, and (4) biofunctional layer in green. The particles shown in panels A-C were synthesized in the NanoMag FP7 project (http://nanomag-project.eu/).…”

Section: Magnetic Cores and Magnetic Particlesmentioning

confidence: 99%

Rotating magnetic particles for lab-on-chip applications – a comprehensive review

2019

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“…Currently, statistically suspect comparisons of relaxivities under different experimental conditions (e.g., field strength) or between CAs are regularly performed and displayed in bar charts or tables . To date, there is no standard protocol for how to best design and analyze a relaxivity experiment . Similar problems have been addressed previously in UV‐Vis spectroscopy and liquid chromatography‐mass spectrometry (LC‐MS) through weighted least squares (WLS), which has also been applied on occasion to relaxivity .…”

Section: Introductionmentioning

confidence: 98%

A novel gamma GLM approach to MRI relaxometry comparisons

Kapre

Zhou

et al. 2020

Magnetic Resonance in Med

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Purpose:To demonstrate that constant coefficient of variation (CV), but nonconstant absolute variance in MRI relaxometry (T 1 , T 2 , R 1 , R 2 ) data leads to erroneous conclusions based on standard linear models such as ordinary least squares (OLS).We propose a gamma generalized linear model identity link (GGLM-ID) framework that factors the inherent CV into parameter estimates. We first examined the effects on calculations of contrast agent relaxivity before broadening to other applications such as analysis of variance (ANOVA) and liver iron content (LIC). Methods: Eight models including OLS and GGLM-ID were initially fit to data obtained on sulfated dextran iron oxide (SDIO) nanoparticles. Both a resampling simulation on the data as well as two separate Monte Carlo simulations (with and without concentration error) were performed to determine mean square error (MSE) and type I error rate. We then evaluated the performance of OLS/GGLM-ID on R 1 repeatability and LIC data sets. Results: OLS had an MSE of 4-5× that of GGLM-ID as well as a type I error rate of 20-30%, whereas GGLM-ID was near the nominal 5% level in the relaxivity study.Only OLS found statistically significant effects of MRI facility on relaxivity in an R 1 repeatability study, but no significant differences were found in a resampling, whereas GGLM was more consistent. GGLM-ID was also superior to OLS for modeling LIC. Conclusions: OLS leads to erroneous conclusions when analyzing MRI relaxometry data. GGLM-ID factors in the inherent CV of an MRI experiment, leading to more reproducible conclusions. K E Y W O R D S coefficient of variation, gamma GLM, MRI relaxometry, relaxivity, repeatability | 1593 KAPRE Et Al.

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Standardisation of magnetic nanoparticles in liquid suspension

Cited by 59 publications

References 156 publications

Synthesis and ESR Study of Transition from Ferromagnetism to Superparamagnetism in La_0.8Sr_0.2MnO₃ Nanomanganite

Synthesis and ESR Study of Transition from Ferromagnetism to Superparamagnetism in La_0.8Sr_0.2MnO₃ Nanomanganite

Rotating magnetic particles for lab-on-chip applications – a comprehensive review

A novel gamma GLM approach to MRI relaxometry comparisons

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Standardisation of magnetic nanoparticles in liquid suspension

Cited by 59 publications

References 156 publications

Synthesis and ESR Study of Transition from Ferromagnetism to Superparamagnetism in La0.8Sr0.2MnO3 Nanomanganite

Synthesis and ESR Study of Transition from Ferromagnetism to Superparamagnetism in La0.8Sr0.2MnO3 Nanomanganite

Rotating magnetic particles for lab-on-chip applications – a comprehensive review

A novel gamma GLM approach to MRI relaxometry comparisons

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Product

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Synthesis and ESR Study of Transition from Ferromagnetism to Superparamagnetism in La_0.8Sr_0.2MnO₃ Nanomanganite

Synthesis and ESR Study of Transition from Ferromagnetism to Superparamagnetism in La_0.8Sr_0.2MnO₃ Nanomanganite