Improving Magnetic Hyperthermia Performance

18 Dec Improving Magnetic Hyperthermia Performance

A team of researchers from the Instituto Italiano di Tecnologia, University of York and University of Southampton have carried out the calorimetric measurements to determine the Specific Absorption Rate (SAR) of some colloidal ferrofluids using our instrument (DM100 Series).  They demonstrate the correlation between the heating efficiency under the influence of an alternating magnetic field and the geometry of the magnetic nanoparticles. These promising results have just published a paper in ACSNano, showing the importance of the particle arrangements and defined geometries and how they affect directly the Specific Absorption Rate (SAR) values and magnetic hyperthermia performance.

Asymmetric Assembling of Iron Oxide Nanocubes for Improving Magnetic Hyperthermia Performance

  • Dina Niculaes, Aidin Lak, George C. Anyfantis, Sergio Marras, Oliver Laslett, Sahitya K Avugadda, Marco Cassani, David Serantes, Ondrej Hovorka, Roy Chantrell, and Teresa Pellegrino

ACS Nano
DOI: 10.1021/acsnano.7b05182

 

ABSTRACT

Asymmetric Assembling of Iron Oxide Nanocubes for Improving Magnetic Hyperthermia Performance

 

Magnetic hyperthermia (MH) based on magnetic nanoparticles (MNPs) is a promising adjuvant therapy for cancer treatment. Particle clustering leading to complex magnetic interactions affects the heat generated by MNPs during MH. The heat efficiencies, theoretically predicted, are still poorly understood because of lack of the control of the fabrication of such clusters with defined geometries and thus their functionality. This study aims to correlate the heating efficiency under MH of individually coated iron oxide nanocubes (IONCs) vs. soft colloidal nanoclusters made of small groupings of nanocubes arranged in different geometries. The controlled clustering of alkyl stabilized IONCs is achieved here during the water transfer procedure by tuning the fraction of the amphiphilic copolymer, poly(styrene-co-maleic anhydride) cumene terminated, to the nanoparticle surface. It is found that increasing the polymer-to-nanoparticle surface ratio leads to the formation of increasingly large nanoclusters with defined geometries. When compared to the individual nanocubes, we show here that controlled grouping of nanoparticles—so-called “dimers” and “trimers” comprised of two and three nanocubes, respectively—increases specific absorption rate (SAR) values, while conversely, forming centrosymmetric clusters having more than four nanocubes leads to lower SAR values. Magnetization measurements and Monte-Carlo based simulations support the observed SAR trend, and reveal the importance of the dipolar interaction effect and its dependence on the details of the particle arrangements within the different clusters.

Keywords: annealing; controlled colloidal clustering; iron oxide nanocubes; magnetic hyperthermia; Monte Carlo simulation; poly(styrene-co-maleic anhydride); specific absorption rate