Influence of clustering on the magnetic properties and hyperthermia performance of iron oxide nanoparticles

Abstract

Clustering of magnetic nanoparticles can drastically change their collective magnetic properties, which in turn may influence their performance in technological or biomedical applications. Here, we investigate a commercial colloidal dispersion (FeraSpinR), which contains dense clusters of iron oxide cores (mean size around 9 nm according to neutron diffraction) with varying cluster size (about 18-56 nm according to small angle x-ray diffraction), and its individual size fractions (FeraSpinXS, S, M, L, XL, XXL). The magnetic properties of the colloids were characterized by isothermal magnetization, as well as frequency-dependent optomagnetic and AC susceptibility measurements. From these measurements we derive the underlying moment and relaxation frequency distributions, respectively. Analysis of the distributions shows that the clustering of the initially superparamagnetic cores leads to remanent magnetic moments within the large clusters. At frequencies below 10 rad s, the relaxation of the clusters is dominated by Brownian (rotation) relaxation. At higher frequencies, where Brownian relaxation is inhibited due to viscous friction, the clusters still show an appreciable magnetic relaxation due to internal moment relaxation within the clusters. As a result of the internal moment relaxation, the colloids with the large clusters (FS-L, XL, XXL) excel in magnetic hyperthermia experiments.

In vivo magnetic particle imaging: angiography of inferior vena cava and aorta in rats using newly developed multicore particles

“…The choice of Resovist (containing the drug substance www.nature.com/scientificreports/ Ferucarbotran) as a measure for comparison with MCP 3 is due to the frequent application of the tracer in MPI studies. Implementation of other commercially available traces with promising MPI characteristics such as perimag 26,27 and synomag-D 28 (micromod Partikeltechnologie GmbH, Rostock, Germany) and comparison with the obtained results would be of interest in future studies. Another general limitation in MPI based on SF is the possible mismatch of the SF-sample used for calibration and the magnetization dynamics of MNP under influence of their specific local environment in vivo [29][30][31][32] , which causes image artifacts and reduced sensitivity of MPI 33 .…”

“…The choice of Resovist (containing the drug substance Ferucarbotran) as a measure for comparison with MCP 3 is due to the frequent application of the tracer in MPI studies. Implementation of other commercially available traces with promising MPI characteristics such as perimag 26 , 27 and synomag-D 28 (micromod Partikeltechnologie GmbH, Rostock, Germany) and comparison with the obtained results would be of interest in future studies.…”

Design and implementation of a low temperature, inductance based high frequency alternating current susceptometer

“…By using the reported by Wetterskog et al using transmission electron microscopy analysis (∼6 nm) but there is a good resemblance of the FeraSpin XS core diameter with recently reported data 19 using X-ray diffraction (XRD), neutron powder-diffraction (ND) and small angle x-ray scattering (SAXS), (∼9 nm). The different values of the core size can be due to different size weightings using different analysis techniques 19 . The low value of τ 0 can be due to magnetic interactions between the magnetic cores.…”

Comparison of the effect of rhodium citrate-associated iron oxide nanoparticles on metastatic and non-metastatic breast cancer cells

“…In this context, iron oxide nanoparticles hold great promise as diagnostic and therapeutic agents in oncology. Their intrinsic physical properties are particularly interesting for simultaneous drug delivery, molecular imaging and applications such as localized hyperthermia (Bender et al 2018;Iv et al 2015). These technical features provide special perspectives for breast cancer treatment and diagnosis, which is especially important because of the high incidence, drug resistance and recurrence risk related to this disease (Low et al 2018;Harmon et al 2015;Karakatsanis et al 2016).…”