Three samples of Fe-S were prepared with different hydrothermal periods (6, 12, and 18 h). X-ray diffraction (XRD) test showed that the first produced sample contained 42.3 wt % of magnetite, 35 wt % of greigite, and 22.7 wt % of pyrite phases. The same phases were formed during the second period but with different wt % ratios. The greigite increased to 67.8 wt % by the third period, while the magnetite and pyrite phases vanished and were associated with a low ratio of the presence of pyrrhotite and FeO2. Scanning electron microscope (SEM) images confirmed the formation of the nanoparticles. The increase in the hydrothermal time produced a reduction in the saturation magnetization (39.8 to 9.1) emu/g and the remanence magnetization (8 to 2.4) emu/g, and increasing in the coercivity. To assess the viability of Michigan Cancer Foundation-7 (MCF-7) and hemolytic disease of the fetus and newborn (HdFn) cells, a colorimetric assay for assessing cell metabolic activity (MTT) was applied to the third sample. The outcome verified iron sulfide's cytocompatibility against HdFn cells even at high concentrations and good anticancer activity against MCF-7 cell lines. The result of the DPPH test confirmed that the third sample had antioxidant activity equivalent to that of ascorbic acid. The influence of hydrothermal treatment time on Fe-S composition was studied. A clear change in the sample phases with the treating period was observed which is associated with a variation in the magnetic properties. Electron microscopy images confirmed the formation of the spherical nanoparticles. The outcome of the anticancer activity against some cancer cells verified that the prepared iron sulfide samples have good anticancer activity against this cancer cell. Also, the study confirmed that the nanoparticles have good antioxidant activity.image
