In Silico Experiments to Explore the Heating Efficiency of Magnetic Nanoparticles in Hyperthermia Preclinical Tests

Abstract

Preclinical tests on murine models are typically performed to evaluate the therapeutic efficacy of novel magnetic nanoparticles (MNPs) in cancer treatment with magnetic hyperthermia. Here, through in silico experiments, in vivo tests are mimicked on a 30 g mouse and a 500 g rat, with the aim of determining the optimal treatment conditions allowing to reach the therapeutic temperature range (40−45 °C) within tumor regions. Various types of MNPs are considered with very different heating properties in terms of specific loss power, varying their administered dose, as well as the frequency and peak amplitude of the magnetic field. The analysis is performed by means of finite element models that solve the low-frequency electromagnetic (EM) field problem and the Pennes' bioheat transfer equation, to calculate the temperature increase in biological tissues due to the combined effects of EM field exposure and MNP activation. The methodology, which can be generalized to any type of MNPs, has permitted to identify the proper doses of MNPs to be administered to the tumor region, as a function of their heating properties and magnetic field parameters, highlighting the conditions that can lead to possible overheating, generation of hot spots or magnetic hyperthermia inefficacy.

Influence of size, volume concentration and aggregation state on magnetic nanoparticle hyperthermia properties versus excitation conditions

“…4c that the heating properties of Fe 3 O 4 NPs can change drastically depending on the field parameters, requiring a careful selection of the excitation conditions during in vivo treatments. 66 As an example, when d = 40 nm an SLP of ∼1050 W g −1 and ∼790 W g −1 can be reached in cases #2 and #1, respectively, while it becomes practically negligible in case #3 for that size. When d = 20 nm, from case #3 to #1 the SLP reduces to approximately one third, passing from ∼1150 W g −1 to ∼340 W g −1 .…”

Magnetic Hyperthermia to Promote Acrylamide Radical Polymerizations

“…These are core−shell NPs with a citrate shell from NanoMaterials Technology Pte Ltd. (known as JHU NPs) and matrix-based NPs constituted by superparamagnetic iron oxide NPs dispersed in a dextran matrix, from micromod Partikeltechnologie GmbH (known as nanomag-D-spio). 58 Their heating properties, also tested through in silico simulations of magnetic hyperthermia applied to murine models, 59 are available from the literature in terms of SLP versus H ̂a and f. 35 In particular, for JHU NPs, when f = 150 kHz, the SLP varies between 150 and 480 W/g in the range of H ̂a 10−40 kA/m, while, when f = 300 kHz, the SLP varies between 50 and 780 W/g in the range of H ̂a 5−20 kA/ m. For nanomag-D-spio NPs, when f = 150 kHz, the SLP varies between 15 and 45 W/g in the range of H ̂a 10−40 kA/ m, while, when f = 300 kHz, the SLP varies between 15 and 70 W/g in the range of H ̂a 5−20 kA/m. As a result of the different heating properties, MNP concentrations on the order of 5 mg/ mL are potentially sufficient for reaching 60 °C and activating the polymerization in 2 min when using JHU NPs and AC magnetic fields with f = 150 kHz and H ̂aa = 40 kA/m (Figure 3D).…”