Synthesis of Ferromagnetic Fe_0.6Mn_0.4O Nanoflowers as a New Class of Magnetic Theranostic Platform for In Vivo T₁‐T₂ Dual‐Mode Magnetic Resonance Imaging and Magnetic Hyperthermia Therapy

Abstract

Uniform wüstite Fe0.6 Mn0.4 O nanoflowers have been successfully developed as an innovative theranostic agent with T1 -T2 dual-mode magnetic resonance imaging (MRI), for diagnostic applications and therapeutic interventions via magnetic hyperthermia. Unlike their antiferromagnetic bulk counterpart, the obtained Fe0.6 Mn0.4 O nanoflowers show unique room-temperature ferromagnetic behavior, probably due to the presence of an exchange coupling effect. Combined with the flower-like morphology, ferromagnetic Fe0.6 Mn0.4 O nanoflowers are demonstrated to possess dual-modal MRI sensitivity, with longitudinal relaxivity r1 and transverse relaxivity r2 as high as 4.9 and 61.2 mm(-1) s(-1) [Fe]+[Mn], respectively. Further in vivo MRI carried out on the mouse orthotopic glioma model revealed gliomas are clearly delineated in both T1 - and T2 -weighted MR images, after administration of the Fe0.6 Mn0.4 O nanoflowers. In addition, the Fe0.6 Mn0.4 O nanoflowers also exhibit excellent magnetic induction heating effects. Both in vitro and in vivo magnetic hyperthermia experimentation has demonstrated that magnetic hyperthermia by using the innovative Fe0.6 Mn0.4 O nanoflowers can induce MCF-7 breast cancer cell apoptosis and a complete tumor regression without appreciable side effects. The results have demonstrated that the innovative Fe0.6 Mn0.4 O nanoflowers can be a new magnetic theranostic platform for in vivo T1 -T2 dual-mode MRI and magnetic thermotherapy, thereby achieving a one-stop diagnosis cum effective therapeutic modality in cancer management.

Advances in Magnetic Nanoparticles for Biomedical Applications

“…Actually, targeted therapies remain a challenge in cancer treatment and are the focus of nanotechnology in order to improve the therapy efficiency and prognosis of disease. An important step toward targeted and higher specific cancer therapy has been given with MNP‐mediated hyperthermia (MH) which is already being used, for example, on the treatment of mice's tumors ( Figure ) …”

“…c) Day 50 photographs of representative mice from test and control groups. Reproduced with permission …”

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