The formation of linear aggregates in magnetic hyperthermia: Implications on specific absorption rate and magnetic anisotropy

Saville, Steven L.; Qi, Bin; Baker, Jonathon N.; Stone, Roland; Camley, R. E.; Livesey, Karen L.; Ye, Longfei; Crawford, T. M.; Mefford, O. Thompson

doi:10.1016/j.jcis.2014.03.007

Cited by 83 publications

(67 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For the MNPs investigated here, the maghemite nanopowder had some aggregation (see DLS results in Table 1), likely due to the lack of surface coatings to stabilize the aqueous dispersions. There have been conflicting views on whether aggregation of MNPs increases or decreases magnetic heating [49–53], and varying magnitudes of magnetic interactions occurring in these two MNP systems (maghemite nanopowder and AP003 MNPs) may affect their SAR in complex ways (as discussed later in this paper). The major factors leading to higher SAR values observed for maghemite nanopowder mainly originate from their larger diameter (where LRT may no longer be valid), and their ferromagnetic nature which can influence the processes contributing to heat generation in these MNPs.…”

Section: Resultsmentioning

confidence: 99%

Determining iron oxide nanoparticle heating efficiency and elucidating local nanoparticle temperature for application in agarose gel-based tumor model

Shah

Dombrowsky

Paulson

et al. 2016

Materials Science and Engineering: C

View full text Add to dashboard Cite

Magnetic iron oxide nanoparticles (MNPs) have been developed for magnetic fluid hyperthermia (MFH) cancer therapy, where cancer cells are treated through the heat generated by application of a high frequency magnetic field. This heat has also been proposed as a mechanism to trigger release of chemotherapy agents. In each of these cases, MNPs with optimal heating performance can be used to maximize therapeutic effect while minimizing the required dosage of MNPs. In this study, the heating efficiencies (or specific absorption rate, SAR) of two types of MNPs were evaluated experimentally and then predicted from their magnetic properties. MNPs were also incorporated in the core of poly(ethylene glycol-b-caprolactone) micelles, co-localized with rhodamine B fluorescent dye attached to polycaprolactone to monitor local, nanoscale temperatures during magnetic heating. Despite a relatively high SAR produced by these MNPs, no significant temperature rise beyond that observed in the bulk solution was measured by fluorescence in the core of the magnetic micelles. MNPs were also incorporated into a macro-scale agarose gel system that mimicked a tumor targeted by MNPs and surrounded by healthy tissues. The agarose-based tumor models showed that targeted MNPs can reach hyperthermia temperatures inside a tumor with a sufficient MNP concentration, while causing minimal temperature rise in the healthy tissue surrounding the tumor.

show abstract

Section: Resultsmentioning

confidence: 99%

Determining iron oxide nanoparticle heating efficiency and elucidating local nanoparticle temperature for application in agarose gel-based tumor model

Shah

Dombrowsky

Paulson

et al. 2016

Materials Science and Engineering: C

View full text Add to dashboard Cite

show abstract

“…Saville et al propose to treat MNP chains as a single magnetic rod with ferromagnetic properties along the direction of particle alignment [14]. This gives again rise to (ferromagnetic) hysteresis losses, increasing the heating as described above.…”

Section: Discussionmentioning

confidence: 99%

Agglomeration of magnetic nanoparticles and its effects on magnetic hyperthermia

Engelmann

Buhl

Baumann

et al. 2017

Current Directions in Biomedical Engineering

View full text Add to dashboard Cite

Magnetic fluid hyperthermia (MFH) is a promising approach for organ-confined tumor treatment. In MFH, magnetic nanoparticles (MNP) are magnetically targeted at the tumor site and heated in an alternating magnetic field. The heat produced by the MNP is used to cause tumor cell death. At the tumor site, MNP bind to the cell membrane and form agglomerates before they are internalized into the intracellular compartments. Intracellular immobilization and the formation of agglomerates influence heating properties of MNP making it difficult to control the local heating inside the tumor. In this study, we investigated MNP agglomerated samples for their heating efficiency. We found an increase in heating of 22 % upon agglomeration. If MNP are additionally immobilized, however, the heating decreases by 30 %. Consequently, due to the binding of bigger MNP agglomerates at cellular level, heating efficiency inside tumors is assumed to decrease.

show abstract

“…20 nm in diameter) superparamagnetic MNPs if not stabilized by long polymer brushes can form linear chain-like aggregates in the presence of an applied external AMF [92]. The measurements were conducted using an AMF with f = 150 kHz and B = 60 mT.…”

Section: Observation Of Magneto-mechanical Actuation In Biologicalmentioning

confidence: 99%

Towards nanomedicines of the future: Remote magneto-mechanical actuation of nanomedicines by alternating magnetic fields

Golovin

Gribanovsky

Golovin

et al. 2015

Journal of Controlled Release

192

156

View full text Add to dashboard Cite

The paper describes the concept of magneto-mechanical actuation of single-domain magnetic nanoparticles (MNPs) in super-low and low frequency alternating magnetic fields (AMFs) and its possible use for remote control of nanomedicines and drug delivery systems. The applications of this approach for remote actuation of drug release as well as effects on biomacromolecules, biomembranes, subcellular structures and cells are discussed in comparison to conventional strategies employing magnetic hyperthermia in a radio frequency (RF) AMF. Several quantitative models describing interaction of functionalized MNPs with single macromolecules, lipid membranes, and proteins (e.g. cell membrane receptors, ion channels) are presented. The optimal characteristics of the MNPs and an AMF for effective magneto-mechanical actuation of single molecule responses in biological and bio-inspired systems are discussed. Altogether, the described studies and phenomena offer opportunities for the development of novel therapeutics both alone and in combination with magnetic hyperthermia.

show abstract

The formation of linear aggregates in magnetic hyperthermia: Implications on specific absorption rate and magnetic anisotropy

Cited by 83 publications

References 48 publications

Determining iron oxide nanoparticle heating efficiency and elucidating local nanoparticle temperature for application in agarose gel-based tumor model

Determining iron oxide nanoparticle heating efficiency and elucidating local nanoparticle temperature for application in agarose gel-based tumor model

Agglomeration of magnetic nanoparticles and its effects on magnetic hyperthermia

Towards nanomedicines of the future: Remote magneto-mechanical actuation of nanomedicines by alternating magnetic fields

Contact Info

Product

Resources

About