Giant Magnetic Heat Induction of Magnesium-Doped γ-Fe 2 O 3 Superparamagnetic Nanoparticles for Completely Killing Tumors.

Magnetic fluid hyperthermia has been recently considered as a Renaissance of cancer treatment modality due to its remarkably low side effects and high treatment efficacy compared to conventional chemotheraphy or radiotheraphy. However, insufficient AC induction heating power at a biological safe range of AC magnetic field (H-appl.f(appl) < 3.0-5.0 x 10(9) A m(-1) s(-1)), and highly required biocompatibility of superparamagnetic nanoparticle (SPNP) hyperthermia agents are still remained as critical challenges for successful clinical hyperthermia applications. Here, newly developed highly biocompatible magnesium shallow doped -Fe2O3 (Mg-0.13 gamma-Fe2O3) SPNPs with exceptionally high intrinsic loss power (ILP) in a range of 14 nH m(2) kg(-1), which is an approximate to 100 times higher than that of commercial Fe3O4 (Feridex, ILP = 0.15 nH m(2) kg(-1)) at H-appl.f(appl) = 1.23 x 10(9) A m(-1) s(-1) are reported. The significantly enhanced heat induction characteristics of Mg-0.13 gamma-Fe2O3 are primarily due to the dramatically enhanced out-of-phase magnetic susceptibility and magnetically tailored AC/DC magnetic softness resulted from the systematically controlled Mg2+ cations distribution and concentrations in octahedral site Fe vacancies of gamma-Fe2O3 instead of well-known Fe3O4 SPNPs. In vitro and in vivo magnetic hyperthermia studies using Mg-0.13-gamma Fe2O3 nanofluids are conducted to estimate bioavailability and biofeasibility. Mg-0.13-gamma Fe2O3 nanofluids show promising hyperthermia effects to completely kill the tumors.