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 ·f < 3.0-5.0 × 10 A m s ), 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 γ-Fe O (Mg -γFe O ) SPNPs with exceptionally high intrinsic loss power (ILP) in a range of 14 nH m kg , which is an ≈100 times higher than that of commercial Fe O (Feridex, ILP = 0.15 nH m kg ) at H ·f = 1.23 × 10 A m s are reported. The significantly enhanced heat induction characteristics of Mg -γFe O are primarily due to the dramatically enhanced out-of-phase magnetic susceptibility and magnetically tailored AC/DC magnetic softness resulted from the systematically controlled Mg cations distribution and concentrations in octahedral site Fe vacancies of γ-Fe O instead of well-known Fe O SPNPs. In vitro and in vivo magnetic hyperthermia studies using Mg -γFe O nanofluids are conducted to estimate bioavailability and biofeasibility. Mg -γFe O nanofluids show promising hyperthermia effects to completely kill the tumors.

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Magnesium‐doped g‐Fe2O3 superparamagnetic nanoparticles with exceptionally high intrinsic loss power of 14 nH m2 kg−1, which is ≈100 times higher than that of commercial Fe3O4, at a physiologically safe range of AC magnetic field (Happlfappl = 1.23 × 109 A m−1 s−1) are developed by Seongtae Bae and co‐workers in article number https://doi.org/10.1002/adma.201704362. Their hyperthermia effect is revealed to be promising for completely killing tumors.

In this study, we investigated the effects of recovery time during magnetic nanofluid hyperthermia (MNFH) on the cell death rate and the heat shock proteins 72 (HSP72) induction behavior in retinal ganglion cells (RGCs-5) to provide a possible solution for highly efficient ocular neuroprotection. The recovery time and the heat duration time during MNFH were systematically controlled by changing the duty cycle of alternating current (AC) magnetic field during MNFH. It was clearly observed that the cell death rate and the HSP72 induction rate had a strong dependence on the recovery time and the optimizated recovery time resulted in maximizing the induction efficiency of HSP72. Controlling the recovery time during MNFH affects not only the cell death rate but also HSP72 induction rate. The cell death rate after MNFH was dramatically decreased by increasing the recovery time during MNFH. However, it was also found that the HSP72 induction rate was slightly decreased by increasing the recovery time. These results indicate that applying the appropriate or optimized recovery time during MNFH can improve the induction efficiency of HSP72 by minimizing the cell death caused by cytotoxic effects of heat.