Hyphenation of Field-Flow Fractionation and Magnetic Particle Spectroscopy

Löwa, Norbert; Radon, Patricia; Gutkelch, Dirk; August, Rinaldo; Wiekhorst, Frank

doi:10.3390/chromatography2040655

Cited by 12 publications

(7 citation statements)

References 24 publications

(31 reference statements)

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“…A suitable detector array could contain, e.g., small-angle X-ray scattering (crystallite size), DLS (hydrodynamic size), multiangle light scattering (core/cluster size), and/or UV-Vis (concentration). This approach has already been shown for the coupling with chromatography [ 23 ]. In this context, a multi-frequency acquisition scheme, as proposed in [ 30 , 35 , 36 , 37 ], would provide further valuable information about the frequency dependence of relaxation times and could be used for parameter estimation.…”

Section: Resultsmentioning

confidence: 92%

“…This is advantageous, for example, for calibration and quality assurance tasks. In addition to synthesis monitoring, further fields of application open up, such as the monitoring of chromatographic separation processes [ 23 ] or magnetic blood purification [ 38 ], which are currently under investigation.…”

Section: Discussionmentioning

confidence: 99%

“…Before entering the sensitive area of the RxC (see Figure 2 a), the particles have already been in an excitation field of constant amplitude for about 2550 periods (i.e., a distance of 10 mm). In addition, the influence of the flow rate on the magnetization dynamics of MNP is below 5% [ 23 ].…”

Section: Methodsmentioning

confidence: 99%

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Novel Benchtop Magnetic Particle Spectrometer for Process Monitoring of Magnetic Nanoparticle Synthesis

et al. 2020

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Magnetic nanoparticles combine unique magnetic properties that can be used in a variety of biomedical applications for therapy and diagnostics. These applications place high demands on the magnetic properties of nanoparticles. Thus, research, development, and quality assurance of magnetic nanoparticles requires powerful analytical methods that are capable of detecting relevant structural and, above all, magnetic parameters. By directly coupling nanoparticle synthesis with magnetic detectors, relevant nanoparticle properties can be obtained and evaluated, and adjustments can be made to the manufacturing process in real time. This work presents a sensitive and fast magnetic detector for online characterization of magnetic nanoparticles during their continuous micromixer synthesis. The detector is based on the measurement of the nonlinear dynamic magnetic response of magnetic nanoparticles exposed to an oscillating excitation at a frequency of 25 kHz, a technique also known as magnetic particle spectroscopy. Our results underline the excellent suitability of the developed magnetic online detection for coupling with magnetic nanoparticle synthesis based on the micromixer approach. The proven practicability and reliability of the detector for process monitoring forms the basis for further application fields, e.g., as a monitoring tool for chromatographic separation processes.

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Section: Resultsmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

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Novel Benchtop Magnetic Particle Spectrometer for Process Monitoring of Magnetic Nanoparticle Synthesis

et al. 2020

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“…The measurements were performed at body temperature ( T = 37 °C) using a commercial MPS device (MPS-3, Bruker, Rheinstetten, Germany), operated at a sinusoidal excitation field (amplitude up to B = 25 mT, fixed frequency of f 0 = 25 kHz). For using MPS in the online detector array with CF3, a flow cell was used, where the MNPs move in a capillary through the MPS detector coil ( B = 25 mT) [ 20 ]. The MPS flow cell consists of a 3D-printed plastic holder for the reproducible fixation and positioning of the capillary.…”

Section: Methodsmentioning

confidence: 99%

Cell Tracking by Magnetic Particle Imaging: Methodology for Labeling THP-1 Monocytes with Magnetic Nanoparticles for Cellular Imaging

Remmo

Löwa

Kosch

et al. 2022

Cells

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Magnetic particle imaging (MPI) is a noninvasive tomographic imaging modality for the quantitative visualization of magnetic nanoparticles (MNPs) with high temporal and spatial resolution. The general capability of MPI for cell tracking (e.g., monitoring living cells labeled with MNPs) has successfully been shown. MNPs in cell culture media are often subjected to structural and magnetic changes. In addition to the deteriorating reproducibility, this also complicates the systematic study of the relationship between the MNP properties and their cellular uptake for MPI. Here, we present a method for the preparation of magnetically labeled THP-1 (Tamm–Horsfall Protein-1) monocytes that are used in MPI cell tracking. The method development was performed using two different MPI tracers, which exhibited electrostatic and steric stabilizations, respectively. In the first step, the interaction between the MNPs and cell culture media was investigated and adjusted to ensure high structural and magnetic stability. Furthermore, the influences of the incubation time, MNP concentration used for cellular uptake, and individual preparation steps (e.g., the washing of cells) were systematically investigated. Finally, the success of the developed loading method was demonstrated by the MPI measurements. The presented systematic investigation of the factors that influence the MNP loading of cells will help to develop a reliable and reproducible method for MPI monocyte tracking for the early detection of inflammation in the future.

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“…Therefore, some techniques are required and applied to reduce the size distribution. So far, several methods have been reported for MNP such as magnetic field flow fractionation filtration [205,206], separation in electric fields [207] and gradient magnetic separation [208].…”

Section: Discussionmentioning

confidence: 99%

Synthesis and characterization of magnetic nanoparticles for biomedical applications

Arsalani¹

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Arsalani, Soudabeh. Synthesis and Characterization of Magnetic Nanoparticles for Biomedical Applications. 2020. 127p. A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Physics, Faculty of Philosophy, Sciences and literature of Ribeirão Preto -SP, 2020.Magnetic nanomaterials with specific size and shape distributions have attracted a large interest in recent years due to their promising properties for biomedical applications. This thesis presents the results of the synthesis and characterization of superparamagnetic iron oxide nanoparticles (SPIONs) for biomedical applications. The first group of SPIONs was prepared by a simple green co-precipitation method at a mild temperature and capping by natural rubber latex (NRL) extracted from Hevea brasiliensis. The results showed core size, size distribution, magnetization and blocking temperature of the magnetic nanoparticles (MNPs) could be controlled by the NRL concentration. Importantly, NRL-coated MNPs showed higher magnetization compared to the bare MNPs that can suggest NRL is an effective stabilizing agent to cover MNPs with enhancing magnetization for biomedical applications. The performance of the bare MNPs and NRL-coated MNPs were investigated by magnetic resonance imaging (MRI) system. MRI results showed R2 relaxation strongly depends on the NRL shell thickness of MNPs and it decreases by increasing the shell thickness of NRL. In addition, the relaxivity ratios (r2/r1) can be controlled by adjusting the concentration of NRL. Therefore, NRL coated MNPs can be considered as effective contrast agents for MRI applications. The second group of SPIONs with fluorescent and radioluminescent properties were synthesized by the thermal decomposition method, covered with oleic acid (OA) and modified by anthracene (AN) and polyvinyl alcohol (PVA) as fluorophore and the dispersion agent in aqueous solution, respectively. This multifunctional nanocomposite exhibited sharp blue emission bands upon exposure to UV and X-ray. Furthermore, the radioluminescence intensity of this nanocomposite showed a linear relation with the X-ray dose rate, that is highly desirable for biomedical applications. The last part of this thesis was devoted to narrow the size distribution of IONP (EMG 700, Ferrotec) coated with anionic surfactants that carried out using low gradient magnetic separation (LGMS) (<15 T/m) method, to improve their performance as magnetic particles imaging (MPI) tracers. Samples before and after LGMS with different concentrations of magnetite (Fe3O4) nanoparticles were imaged in a preclinical MPI scanner. The images of the samples after separation showed an improved MPI resolution. Furthermore, we show that the LGMS technique is capable of separating larger MNP entities from the suspension in a short period of time which allowed us to adjust the size distribution and magnetic properties of MNP via timecontrolled magnetic separation.

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Hyphenation of Field-Flow Fractionation and Magnetic Particle Spectroscopy

Cited by 12 publications

References 24 publications

Novel Benchtop Magnetic Particle Spectrometer for Process Monitoring of Magnetic Nanoparticle Synthesis

Novel Benchtop Magnetic Particle Spectrometer for Process Monitoring of Magnetic Nanoparticle Synthesis

Cell Tracking by Magnetic Particle Imaging: Methodology for Labeling THP-1 Monocytes with Magnetic Nanoparticles for Cellular Imaging

Synthesis and characterization of magnetic nanoparticles for biomedical applications

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