Magnetically enhanced cytotoxicity of paramagnetic selenium-ferroferric oxide nanocomposites on human osteoblast-like MG-63 cells

We use quartz crystal microbalance (QCM), 3-(4,5-dimethylthizaol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and fluorescence/optical microscopic inspections to investigate the cytotoxicity of paramagnetic selenium-ferroferric oxide (Se-Fe3O4) nanocomposites on human osteoblast-like MG-63 cells. The nearly spherical Se-Fe3O4 nanocomposites of 40–50 nm diameter, as characterized by transmission electron microscopy (TEM), are synthesized through reduction of selenious acid by ascorbic acid in the presence of nanosized Fe3O4. The QCM technique is employed for the first time to monitor the toxicity of Se-Fe3O4 on tumor cells in a real-time manner. We find that the Se-Fe3O4 nanocomposites are able to induce cell apoptosis in a dose-dependent way, and an external magnetic field increases the cytotoxicity. The results obtained from MTT assay as well as fluorescence and inverted optical microscopy experiments are consistent with that from QCM experiments, indicating that the QCM technique as a simple, inexpensive and dynamic tool is promising in studying the magnetic effects of many paramagnetic drugs on the cells for better understanding of the relevant magneto-chemotherapy processes.