Asymmetric Assembling of Iron Oxide Nanocubes for Improving Magnetic Hyperthermia Performance

Abstract

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 a lack of 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) versus 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” composed 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.

Preparation of Scalable Silica‐Coated Iron Oxide Nanoparticles for Nanowarming

“…Niculaes et al reported that small iron oxide nanocube clusters (dimers and trimers) increased specific absorption rate (SAR) values, while centrosymmetric clusters having more than four cores led to lower SAR values. [28] Moreover, 1D (chain) arrangement IONPs also increased heating ability due to the dipolar interaction effect. [28,29] Overall, the multicored sIONPs did not significantly affect the heating ability of sIONPs, which will be discussed later (see Section 2.2.3).…”

“…[28] Moreover, 1D (chain) arrangement IONPs also increased heating ability due to the dipolar interaction effect. [28,29] Overall, the multicored sIONPs did not significantly affect the heating ability of sIONPs, which will be discussed later (see Section 2.2.3).…”

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

“…The coating of magnetic nanoclusters seems to be a suitable strategy to create colloidally-stable solutions of nanoparticles aggregates taking advantage of magnetic and heating properties of different geometries. Niculaes et al [158] prepared and compared oleic acid-coated iron oxide nanocubes with different geometries -single nanocubes, dimer and trimer assemblies, and centrosymmetric structures (with more than 4 nanocubes) -in terms of their magnetic properties and SAR values ( Figure 9A-C). The SAR value of dimer and trimer structures was higher (253 W/g) than the one obtained for individual nanocubes (213 W/g) and a significantly decrease was observed for centrosymmetric assemblies (184 W/g).…”

“…TEM images of dimer and trimer (A) and centrosymmetric (with more than 4 nanocubes) (B) iron oxide nanoclusters; (C) SAR values of the different nanoassemblies shows that dimer and trimer structures have the highest SAR values. Adapted from[158] with permission from American Chemical Society 2020.…”

Hadron Therapy, Magnetic Nanoparticles and Hyperthermia: A Promising Combined Tool for Pancreatic Cancer Treatment

“…On the contrary, healthy tissues are kept safe because they are rarely in conditions of hypoxia and high acidity. The local heating of tumor tissue has been historically realized in different ways, e.g., bath heating [ 18 ], microwave irradiation [ 19 ], radiofrequency waves [ 20 ], focused ultrasounds [ 21 , 22 ], capacitance hyperthermia [ 23 ], concentrated laser light [ 24 ], magnetic fluid hyperthermia (MFH) [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ] and, more recently, innovative techniques resulting from the coupling of different types of hyperthermia (for example, magnetic and ultrasonic hyperthermia or magnetic hyperthermia and phototherapy [ 35 , 36 ]). In a relatively recent literature-based review, Peeken et al [ 37 ] show the currently used hyperthermia techniques for heat delivery and temperature control, remarking the different modes of action of Hyp.…”