Abstract
MRI (Magnetic Resonance Imaging)-guided magnetic nanofluid hyperthermia (MNFH) is highly desirable in cancer treatment because it can allow for diagnosis, therapeutics, and prognosis simultaneously. However, the application of currently developed iron-oxide based superparamagnetic nanoparticles (IOSPNPs) for a MRI-guided MNFH agent is technically limited by the low AC heat induction power at the physiologically tolerable range of AC magnetic field (HAC,safe), and the low transverse r2-relaxivity responsible for the insufficient heating of cancers, and the low resolution of contrast imaging, respectively. Here, pseudo single domain colloidal NixZn1-x-γFe2O3 (x = 0.6) superparamagnetic nanoparticle (NiZn-γFe2O3 PSD-SPNP) physically and theoretically designed at the HAC,safe, specifically by the applied frequency, is proposed for a highly enhanced MRI-guided MNFH agent application. The NiZn-γFe2O3 PSD-SPNP showed the superparamagnetic characteristics, significantly enhanced AC heat induction performance, and highly improved saturation magnetization that are desirable for highly efficient MRI-guided MNFH agent applications. According to the analyzed results, the remarkably enhanced effective relaxation time constant and its dependent out-of-phase magnetic susceptibility as well as the DC/AC magnetic softness optimized by the PSD-SPNP at the HAC,safe were revealed as the main physical reason for the significance. All the fundamental in-vitro and in-vivo experimental results demonstrated that the physically designed NiZn-γFe2O3 PSD-SPNP is bio-technically feasible for a highly efficient MRI-guided MNFH agent for future cancer nanomedicine.