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

Abstract

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.

In vitro hyperthermic effect of magnetic fluid on cervical and breast cancer cells

“…4 b). A similar 50% decrease in SAR was also reported by Makridis et al 18 and Shah et al 41 for ferrite-based near 10 nm size MNPs and 1.5% agarose gel system. The decrease in specific absorption rate for agarose gel can be attributed to hindered Brownian movement of particles due to agarose gel.…”

Hyperthermia Effect of Nanoclusters Governed by Interparticle Crystalline Structures

“…Magnetic fluid hyperthermia (MFH) using magnetic nanoparticles as heat mediators has attracted interest for cancer therapy because of its noninvasiveness, localized therapeutic capability, and lack of therapeutic limits depending on the type of cancer. − The heat generation capability of iron oxide, the most frequently employed heat generator platform, can be controlled by doping of other metals or varying the size or shape (Table S1). For example, the introduction of dopants such as Co, Mn, or Zn can increase the magnetic anisotropy, ,− leading to enhanced heat generation.…”

Magnetothermal Miniature Reactors Based on Fe3O4 Nanocube‐Coated Liquid Marbles

“…The results revealed that the Fe 3 O 4 nanocubes exhibited typical superparamagnetic behaviors (Figure S1A, Supporting Information), and the 18.4 nm Fe 3 O 4 nanocubes achieved higher saturation during a shorter field exposure time. Additionally, as different nanoparticle anisotropy would contribute to different heating capability, [ 12 ] this may explain why the 18.4 nm iNLMs showed the highest magnetothermal efficiency under AMF. Accordingly, the 18.4 nm iNLMs were selected for subsequent experiments.…”