Magnetic particle imaging scanner with 10-kHz drive-field frequency

Schilling, Meinhard; Ludwig, Frank; Kuhlmann, Christian; Wawrzik, Thilo

doi:10.1515/bmt-2013-0014

Cited by 19 publications

(5 citation statements)

References 28 publications

(32 reference statements)

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“…Magnetic particle imaging (MPI) directly measures the spatial distribution of MNP concentration using the magnetic response of the MNPs to drive and selection magnetic fields [24][25][26][27]. Furthermore, multi-color MPI, in principle, allows the imaging of biomolecules in addition to concentration via the measurements of nanoparticle relaxation [28,29].…”

Section: Introductionmentioning

confidence: 99%

Magnetic nanoparticle-based biomolecule imaging with a scanning magnetic particle spectrometer

2020

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This study reports on a wash-free, inexpensive and sensitive approach of biomolecule imaging with magnetic nanoparticles (MNPs) via a custom-built scanning magnetic particle spectrometer (SMPS). Streptavidin-coated MNPs are used as magnetic biomarkers for the detection of Immunoglobulin G (IgG) conjugated with biotin (IgG-Biotin) while five samples with differentconcentration IgG-Biotin are prepared for experiments. The measurements of the ac susceptibility indicate that the conjugation of the IgG-Biotin onto the surface of the MNPs forms cross-linking between the MNPs, thus increasing the characteristic Brownian relaxation time from 0.627 to 1.448 ms. The ratio of the 3rd to the 1st harmonics is measured on the samples with different-concentration IgG-Biotin in ac magnetic fields with a frequency ranging from about 300 Hz to 2 kHz. It shows that the measurement sensitivity of the IgG-Biotin concentration decreases from 4.62×10 -3 to 0.39×10 -3 nM −1 with increasing excitation frequency. Phantom images of the harmonic ratio, measured with the SMPS, indicate that unbound and bound MNPs can be easily distinguished. Furthermore, the excitation frequency dependence of the contrast-to-noise ratio of the images is discussed based on the measurement sensitivity and the standard deviation of the measured image intensity. This study demonstrates the feasibility of the SMPS for imaging biomolecules bound onto the MNPs, which is of great interest to disease diagnostics and therapy.

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Section: Introductionmentioning

confidence: 99%

Magnetic nanoparticle-based biomolecule imaging with a scanning magnetic particle spectrometer

2020

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“…Recent literature have shown that the drive waveform affects MPI spatial resolution 29 30 31 32 33 34 35 . Unfortunately, current MPI hardware is limited to only sinusoids at a few discrete frequencies 2 3 26 27 28 36 37 38 39 40 41 42 . Multiple simultaneous frequencies (Philips-Bruker 3D Fast MPI demonstrator scanner 15 ) is limited to a narrow range (24.51 kHz, 25.25 kHz, and 26.04 kHz).…”

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confidence: 99%

A High-Throughput, Arbitrary-Waveform, MPI Spectrometer and Relaxometer for Comprehensive Magnetic Particle Optimization and Characterization

Tay

Goodwill

Hensley

et al. 2016

Sci Rep

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Magnetic Particle Imaging (MPI) is a promising new tracer modality with zero attenuation deep in tissue, high contrast and sensitivity, and an excellent safety profile. However, the spatial resolution of MPI is limited to around 1 mm currently and urgently needs to be improved for clinical applications such as angiography and brain perfusion. Although MPI resolution is highly dependent on tracer characteristics and the drive waveforms, optimization is limited to a small subset of possible excitation strategies by current MPI hardware that only does sinusoidal drive waveforms at very few frequencies. To enable a more comprehensive and rapid optimization of drive waveforms for multiple metrics like resolution and signal strength simultaneously, we demonstrate the first untuned MPI spectrometer/relaxometer with unprecedented 400 kHz excitation bandwidth and capable of high-throughput acquisition of harmonic spectra (100 different drive-field frequencies in only 500 ms). It is also capable of arbitrary drive-field waveforms which have not been experimentally evaluated in MPI to date. Its high-throughput capability, frequency-agility and tabletop size makes this Arbitrary Waveform Relaxometer/Spectrometer (AWR) a convenient yet powerfully flexible tool for nanoparticle experts seeking to characterize magnetic particles and optimize MPI drive waveforms for in vitro biosensing and in vivo imaging with MPI.

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“…Regarding the magnetic properties of the five individual synthesis runs, Figure 2 shows the mean and the standard variation (plotted as uncertainty bar) of the characteristic MPS parameters A 3 *, A 5 / A 3 , and ϕ 3 of the five individual runs synthesized either by micromixer (red) or batch synthesis (green). The specific amplitude A 3 * was a measure of the sensitivity of the MNP to give a dynamic magnetization response at a chosen excitation frequency f 0 per unit amount of iron, whereas the ratio A 5 / A 3 could be considered as a parameter to describe the shape of the harmonics spectrum [ 59 , 60 , 61 ]. Finally, phase ϕ 3 was related to the relaxation effects of the MNP and parametrized the lag of the MNP moments to follow the excitation field.…”

Section: Resultsmentioning

confidence: 99%

Micromixer Synthesis Platform for a Tuneable Production of Magnetic Single-Core Iron Oxide Nanoparticles

et al. 2020

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Micromixer technology is a novel approach to manufacture magnetic single-core iron oxide nanoparticles that offer huge potential for biomedical applications. This platform allows a continuous, scalable, and highly controllable synthesis of magnetic nanoparticles with biocompatible educts via aqueous synthesis route. Since each biomedical application requires specific physical and chemical properties, a comprehensive understanding of the synthesis mechanisms is not only mandatory to control the size and shape of desired nanoparticle systems but, above all, to obtain the envisaged magnetic particle characteristics. The accurate process control of the micromixer technology can be maintained by adjusting two parameters: the synthesis temperature and the residence time. To this end, we performed a systematic variation of these two control parameters synthesizing magnetic nanoparticle systems, which were analyzed afterward by structural (transmission electron microscopy and differential sedimentation centrifugation) and, especially, magnetic characterization methods (magnetic particle spectroscopy and AC susceptibility). Furthermore, we investigated the reproducibility of the microtechnological nanoparticle manufacturing process compared to batch preparation. Our characterization demonstrated the high magnetic quality of single-core iron oxide nanoparticles with core diameters in the range of 20 nm to 40 nm synthesized by micromixer technology. Moreover, we demonstrated the high capability of a newly developed benchtop magnetic particle spectroscopy device that directly monitored the magnetic properties of the magnetic nanoparticles with the highest sensitivity and millisecond temporal resolution during continuous micromixer synthesis.

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Magnetic particle imaging scanner with 10-kHz drive-field frequency

Cited by 19 publications

References 28 publications

Magnetic nanoparticle-based biomolecule imaging with a scanning magnetic particle spectrometer

Magnetic nanoparticle-based biomolecule imaging with a scanning magnetic particle spectrometer

A High-Throughput, Arbitrary-Waveform, MPI Spectrometer and Relaxometer for Comprehensive Magnetic Particle Optimization and Characterization

Micromixer Synthesis Platform for a Tuneable Production of Magnetic Single-Core Iron Oxide Nanoparticles

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