Monodispersed MnxZn1-xFe2O4 magnetic nanoparticles of 8 nm are synthesized and encapsulated
in amphiphilic block copolymer for development of the hydrophilic magnetic nanoclusters
(MNCs). These MNCs exhibit superparamagnetic characteristics, high specific absorption
rate (SAR), large saturation magnetization (Ms), excellent stability, and good biocompatibility.
MnFe2O4 and Mn0.6Zn0.4Fe2O4 are selected as optimum compositions for the MNCs (MnFe2O4/MNC
and Mn0.6Zn0.4Fe2O4/MNC) and employed for magnetic fluid hyperthermia (MFH) in vitro.
To ensure biosafety of MFH, the parameters of alternating magnetic field (AMF) and
exposure time are optimized with low frequency, f, and strength of applied magnetic
field, Happlied. Under optimized conditions, MFH of MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC
result in cancer cell death rate up to 90% within 15 min. The pathway of cancer cell
death is identified as apoptosis, which occurs in mild hyperthermia near 43 °C. Both
MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC show similar efficiencies on drug-sensitive and
drug-resistant cancer cells. On the basis of these findings, those MnxZn1-xFe2O4 nanoclusters
can serve as a promising candidate for effective targeting, diagnosis, and therapy
of cancers. The multimodal cancer treatment is also possible as amphiphilic block
copolymer can encapsulate, in a similar fashion, different nanoparticles, hydrophobic
drugs, and other functional molecules.