Low-Dimensional Assemblies of Magnetic MnFe 2 O 4 Nanoparticles and Direct In Vitro Measurements of Enhanced Heating Driven by Dipolar Interactions: Implications for Magnetic Hyperthermia

SANZ, BEATRIZ; CABREIRA-GOMES, RAFAEL; TORRES, TEOBALDO E.; VALDÉS, DANIELA P.; LIMA, ENIO; DE BIASI, EMILIO; ZYSLER, ROBERTO D.; IBARRA, M. RICARDO; GOYA, GERARDO F.

ACS Applied Nano Materials

American Physical Society

Año: 2020

2574-0970

Magnetic fluid hyperthermia (MFH), the procedure of raising thetemperature of tumor cells using magnetic nanoparticles (MNPs) as heating agents, hasproven successful in treating some types of cancer. However, the low heating powergenerated under physiological conditions makes necessary a high local concentration ofMNPs at tumor sites. Here, we report how the in vitro heating power of magnetically softMnFe2O4 nanoparticles can be enhanced by intracellular low-dimensional clustersthrough a strategy that includes: a) the design of the MNPs to retain Néel magneticrelaxation in high viscosity media, and b) culturing MNP-loaded cells under magneticfields to produce elongated intracellular agglomerates. Our direct in vitro measurementsdemonstrated that the specific loss power (SLP) of elongated agglomerates (SLP=57633 W/g) induced by culturing BV2 cells in situ under a dc magnetic field wasincreased by a factor of 2 compared to the SLP=30525 W/g measured in aggregatesfreely formed within cells. A numerical mean-field model that included dipolarinteractions quantitatively reproduced the SLPs of these clusters both in phantoms andin vitro, suggesting that it captures the relevant mechanisms behind power losses underhigh-viscosity conditions. These results indicate that in situ assembling of MNPs intolow-dimensional structures is a sound possible way to improve the heating performancein MFH