Magnetic Fluid Hyperthermia-Induced Apoptosis: Evaluating the Effect of Ho-Doped Mn–Zn Magnetic Nanoparticles on Cervical, Breast, and Bone Cancer Cells in Vitro

Doping rare-earth metals is known to enhance the efficiency of magnetic nanoparticles and, consequently, improve magnetic fluid hyperthermia (MFH), which is emerging as a promising anticancer therapeutic strategy with expected minimal side effects. In this study, the synthesis of holmium (Ho)-doped temperature-sensitive Mn-Zn ferrite nanoparticles using the chemical coprecipitation method is reported. The biocompatibility and intracellular uptake of the synthesized fluid were investigated by using MTT assay- and Prussian blue staining across a variety of cancer cell lines, including cervical (HeLa), breast (MCF-7), and bone (MG-63). Moreover, following MFH, apoptotic cell death was confirmed using Hoechst/PI staining and quantified through flow cytometry after Annexin-V labeling. The expression of selected apoptotic proteins was demonstrated by western blotting. The cells demonstrated the biocompatibility and fair internalization of the magnetic fluid at concentrations sufficient for MFH. Combined intra- and extracellular MFH studies revealed the effective induction of apoptosis in these cells. The findings highlight the potential of Ho-doped Mn-Zn magnetic fluid for cancer therapeutics through MFH.