Magnetorelaxometry procedures for quantitative imaging and characterization of magnetic nanoparticles in biomedical applications

Liebl, Maik; Wiekhorst, Frank; Eberbeck, Dietmar; Radon, Patricia; Gutkelch, Dirk; Baumgarten, Daniel; Steinhoff, Uwe; Trahms, Lutz

doi:10.1515/bmt-2015-0055

Cited by 41 publications

(63 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The latter experimental technique is known as magnetorelaxometry (MRX). In many cases, MRX as a laboratory test is more preferable in comparison with magnetic spectroscopy, in particular, due to its much easier technical implementation [8,9,10]. …”

Section: Introduction: Magnetorelaxometry In Linear Approximationmentioning

confidence: 99%

Magnetorelaxometry in the Presence of a DC Bias Field of Ferromagnetic Nanoparticles Bearing a Viscoelastic Corona

Rusakov

Raǐkher

2018

Sensors

View full text Add to dashboard Cite

With allowance for orientational Brownian motion, the magnetorelaxometry (MRX) signal, i.e., the decay of magnetization generated by an ensemble of ferromagnet nanoparticles, each of which bears a macromolecular corona (a loose layer of polymer gel) is studied. The rheology of corona is modelled by the Jeffreys scheme. The latter, although comprising only three phenomenological parameters, enables one to describe a wide spectrum of viscoelastic media: from linearly viscous liquids to weakly-fluent gels. The “transverse” configuration of MRX is considered where the system is subjected to a DC (constant bias) field, whereas the probing field is applied perpendicularly to the bias one. The analysis shows that the rate of magnetization decay strongly depends on the state of corona and slows down with enhancement of the corona elasticity. In addition, for the case of “transverse” MRX, we consider the integral time, i.e., the characteristic that is applicable to relaxation processes with an arbitrary number of decay modes. Expressions for the dependence of the integral time on the corona elasticity parameter and temperature are derived.

show abstract

Section: Introduction: Magnetorelaxometry In Linear Approximationmentioning

confidence: 99%

Magnetorelaxometry in the Presence of a DC Bias Field of Ferromagnetic Nanoparticles Bearing a Viscoelastic Corona

Rusakov

Raǐkher

2018

Sensors

View full text Add to dashboard Cite

show abstract

“…The decaying field measurements can be used to localize the accumulation of the underlying SPION. SPMR is a highly sensitive technique for the in vivo labeling and detection of tumor cells (at the level of a few thousands cells) by conjugating SPION with antibodies that can bound with specific tumor types (Hathaway et al 2011, Eberbeck et al 2009, Liebl et al 2015, Trahms 2015). For bounded SPION, the decay process is usually long and can last several seconds due to the Neel mechanism (Neel 1955).…”

Section: Introductionmentioning

confidence: 99%

Development of advanced signal processing and source imaging methods for superparamagnetic relaxometry

Huang¹,

Anderson²,

Huang³

et al. 2017

Phys. Med. Biol.

View full text Add to dashboard Cite

Superparamagnetic Relaxometry (SPMR) is a highly sensitive technique for the in vivo detection of tumor cells and may improve early stage detection of cancers. SPMR employs superparamagnetic iron oxide nanoparticles (SPION). After a brief magnetizing pulse is used to align the SPION, SPMR measures the time decay of SPION using Super-conducting Quantum Interference Device (SQUID) sensors. Substantial research has been carried out in developing the SQUID hardware and in improving the properties of the SPION. However, little research has been done in the pre-processing of sensor signals and post-processing source modeling in SPMR. In the present study, we illustrate new pre-processing tools that were developed to: 1) remove trials contaminated with artifacts, 2) evaluate and ensure that a single decay process associated with bounded SPION exists in the data, 3) automatically detect and correct flux jumps, and 4) accurately fit the sensor signals with different decay models. Furthermore, we developed an automated approach based on multi-start dipole imaging technique to obtain the locations and magnitudes of multiple magnetic sources, without initial guesses from the users. A regularization process was implemented to solve the ambiguity issue related to the SPMR source variables. A procedure based on reduced chi-square cost-function was introduced to objectively obtain the adequate number of dipoles that describe the data. The new pre-processing tools and multi-start source imaging approach have been successfully evaluated using phantom data. In conclusion, these tools and multi-start source modeling approach substantially enhance the accuracy and sensitivity in detecting and localizing sources from the SPMR signals. Furthermore, multi-start approach with regularization provided robust and accurate solutions for a poor SNR condition similar to the SPMR detection sensitivity in the order of 1000 cells. We believe such algorithms will help establishing the industrial standards for SPMR when applying the technique in pre-clinical and clinical settings.

show abstract

“…oncology, cardiovascular medicine, radiology, to mention just a few. Some of the papers were financially supported by Deutsche Forschungsgemeinschaft in the frame of PAK151 [6,13,16,19,20].…”

mentioning

confidence: 99%

“…they have to be designed in a way so that they perform best as a drug carrier or a heat dissipater [6], respectively. These physical properties have to be characterised by sophisticated measurement techniques in-vitro [16] as well as in a model simulating the in-vivo situation [12]. With this background methodical and experimental studies can provide a deeper understanding of the mechanisms underlying magnetic drug targeting [20,21] and thermoablation [26].…”

mentioning

confidence: 99%

“…These techniques make directly use of the superparamagnetism of the particles to obtain quantitative information on their distribution in the tissue. Such methods may be useful for therapy control [9,16] as well as for the general diagnosis and detection of cancerous tissue [4]. Note that also MPI has the potential to provide such quantitative information with outstanding sensitivity and resolution.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Magnetic nanoparticles for biomedical applications

Trahms

2015

Biomedical Engineering / Biomedizinische Technik

Self Cite

View full text Add to dashboard Cite

Magnetorelaxometry procedures for quantitative imaging and characterization of magnetic nanoparticles in biomedical applications

Abstract: These MRX based measurement and analysis procedures have substantially supported the development of MNP based biomedical applications.

Cited by 41 publications

References 22 publications

Magnetorelaxometry in the Presence of a DC Bias Field of Ferromagnetic Nanoparticles Bearing a Viscoelastic Corona

Magnetorelaxometry in the Presence of a DC Bias Field of Ferromagnetic Nanoparticles Bearing a Viscoelastic Corona

Development of advanced signal processing and source imaging methods for superparamagnetic relaxometry

Magnetic nanoparticles for biomedical applications

Contact Info

Product

Resources

About