Magnetic Characterization of Iron Oxide Nanoparticles for Biomedical Applications

Maldonado-Camargo, Lorena; Unni, Mythreyi; Rinaldi, Carlos

doi:10.1007/978-1-4939-6840-4_4

Cited by 84 publications

(50 citation statements)

References 36 publications

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“…Nanoparticles were also embedded in a TEGDMA matrix using a technique described previously in order to perform more detailed magnetic characterization 27 . These characterizations included magnetization versus magnetic field (MH) curves taken at 295, 305 and 315 K, plotted as a function of the ratio of magnetic field to absolute temperature, to verify superparamagnetic behavior.…”

Section: Methodsmentioning

confidence: 99%

“…The value of the blocking temperature T B was estimated by applying a simple parabolic fit to the portion of the ZFC curve where the peak in measured magnetization occurred. Equation (12) below was then used to calculate the effective anisotropy constant using the Néel model, accounting for the dispersity in magnetic diameters 27 . Here, K m is the effective magnetic anisotropy constant of the particles, k B is the Boltzmann's constant, T B is the blocking temperature, D mv is the volume weighted median magnetic diameter from the monomodal fit performed above, τ obs is the observation time, τ 0 is the attempt frequency (assumed widely to be 10 -9 s), ln σ g is the geometric deviation of the magnetic diameter distribution obtained above, and T rate is the temperature sweep rate of our ZFC/FC measurements, equal to 2 K/min in all measurements performed.…”

Section: Methodsmentioning

confidence: 99%

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Long circulating tracer tailored for magnetic particle imaging

et al. 2021

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Superparamagnetic iron oxide nanoparticle (SPION) tracers possessing long blood circulation time and tailored for magnetic particle imaging (MPI) performance are crucial for the development of this emerging molecular imaging modality. Here, single-core SPION MPI tracers coated with covalently bonded polyethyelene glycol (PEG) brushes were obtained using a semi-batch thermal decomposition synthesis with controlled addition of molecular oxygen, followed by an optimized PEG-silane ligand exchange procedure. The physical and magnetic properties, MPI performance, and blood circulation time of these newly synthesized tracers were compared to those of two commercially available SPIONs that were not tailored for MPI but are used for MPI: ferucarbotran and PEG-coated Synomag ® -D. The new tailored tracer has MPI sensitivity that is ~3-times better than the commercial tracer ferucarbotran and much longer circulation half-life than both commercial tracers (t 1/2 =6.99 h for the new tracer, vs t 1/2 =0.59 h for ferucarbotran, and t 1/2 =0.62 h for PEG-coated Synomag ® -D).

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Long circulating tracer tailored for magnetic particle imaging

et al. 2021

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“…The suspension cross-linking process was successfully used for the synthesis of chitosan functionalized metal oxide microparticles (MC2), where after immobilization, the highest enzyme activity was obtained (79.0%). Also, MC2 microparticles have larger particle size diameters than MC3 nanoparticles and much higher saturation magnetization; the magnetic properties of nanoparticles are important in applications where an external magnetic field is used [ 73 ]. However, the activity of immobilized ChOx on MC3 nanoparticles is lower.…”

Section: Outcome Of the Different Coating Methodsmentioning

confidence: 99%

Development of Chitosan Functionalized Magnetic Nanoparticles with Bioactive Compounds

2020

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In this study, magnetic maghemite nanoparticles, which belong to the group of metal oxides, were functionalized with chitosan, a non-toxic, hydrophilic, biocompatible, biodegradable biopolymer with anti-bacterial effects. This was done using different synthesis methods, and a comparison of the properties of the synthesized chitosan functionalized maghemite nanoparticles was conducted. Characterization was performed using scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Characterizations of size distribution were performed using dynamic light scattering (DLS) measurements and laser granulometry. A chitosan functionalization layer was confirmed using potentiometric titration on variously synthesized chitosan functionalized maghemite nanoparticles, which is important for further immobilization of bioactive compounds. Furthermore, after activation of chitosan functionalized maghemite nanoparticles with glutaraldehyde (GA) or pentaethylenehexamine (PEHA), immobilization studies of enzyme cholesterol oxidase (ChOx) and horseradish peroxidase (HRP) were conducted. Factors influencing the immobilization of enzymes, such as type and concentration of activating reagent, mass ratio between carrier and enzyme, immobilization time and enzyme concentration, were investigated. Briefly, microparticles made using the chitosan suspension cross-linking process (MC2) proved to be the most suitable for obtaining the highest activity of immobilized enzyme, and nanoparticles functionalized with chitosan using the covalent binding method (MC3) could compete with MC2 for their applications.

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“…From this measurement, the saturation magnetization was found to be around 99 A·m 2 /kg Fe , or 69 A·m 2 /kg magnetite . The magnetic diameter was evaluated to be 9.24 nm (geometric deviation of ln σ = 0.553) by fitting the equilibrium curve to the Langevin function (Maldonado-Camargo et al 2017). Surprisingly, the magnetic diameter was found to be larger than the physical diameter, contrary to the usual observation of iron oxide nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

Benchtop magnetic particle relaxometer for detection, characterization and analysis of magnetic nanoparticles

et al. 2018

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This paper presents the design, construction, and testing of a magnetic particle relaxometer (MPR) to assess magnetic nanoparticle response to dynamic magnetic fields while subjected to a bias field. The designed MPR can characterize magnetic particles for use as tracers in magnetic particle imaging (MPI), with the variation of an applied bias field emulating the scan of the MPI field free point. The system applies a high-frequency time-varying excitation field (up to 45 mT at 30 kHz), while slowly ramping a bias field (±100 mT in 1 s). The time-resolved response of the sample is measured using an inductive sensing coil system, made of a pick-up coil and a rotating and translating balancing coil to finely cancel the induction feed-through from the excitation field. A post-processing algorithm is presented to extract the tracer response related to the point spread function for MPI applications, and the performance of the MPR is demonstrated using superparamagnetic iron oxide particles (ferucarbotran).

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Magnetic Characterization of Iron Oxide Nanoparticles for Biomedical Applications

Cited by 84 publications

References 36 publications

Long circulating tracer tailored for magnetic particle imaging

Long circulating tracer tailored for magnetic particle imaging

Development of Chitosan Functionalized Magnetic Nanoparticles with Bioactive Compounds

Benchtop magnetic particle relaxometer for detection, characterization and analysis of magnetic nanoparticles

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