Low-dimensional assemblies of magnetic nanoparticles improve in vitro heating power through dipolar Interactions

B. SANS; R. CABREIRA-GOMES; T. TORRES MOLINA; D. VALDÉS; E. LIMA JR.; E. DE BIASI; R.D. ZYSLER; M.R. IBARRA; G.F. GOYA

Brasilia

Congreso; 5th International Conference on Nanoscience, Nanotechnology and Nanobiotechnology (3NANO); 2019

Universidad de Brasilia

Magneticfluid hyperthermia (MFH) is an oncology clinical therapy consisting of raisingthe temperature of tumor cells using magnetic nanoparticles (MNPs) as heating agents.Although MFH has proven successful in treating some types of cancer, the lowheating power generated under physiological conditions is the main bottleneckfor making it competitive against other current cancer therapies. This lowheating power makes necessary to have a high local concentration of MNPs attumor sites, which rise toxicological question when applied in animal models. Here,we report how the heating power of MNPs in vitro can be enhanced byintracellular low-dimensional clusters through a twofold strategy thatincludes: a) the design of the MNPs to retain Néel magnetic relaxation in highviscosity media, and b) culturing MNP-loaded cells under magnetic fields toproduce elongated intracellular agglomerates. Our systematic in vitroexperiments demonstrated that the specific loss power (SLP) of elongatedagglomerates induced in situ bya dc magnetic field exhibited a »2-fold increase compared to the SLP from aggregatesfreely formed within cells. A numerical mean-field model that included dipolarinteractions quantitatively reproduced the SLPs of these clusters both inphantoms and in vitro, suggesting that it captures the relevant mechanismsbehind power losses under high-viscosity conditions. These results indicatethat in situ assembling of MNPs into low-dimensional structures can helpimprove the heating performance in MFH.