In vitro toxicity evaluation of ultra-small MFe2O4 (M = Fe, Mn, Co) nanoparticles using A549 cells

As ferrite nanoparticles (MFe2O4) have been widely used in biomedical field, their safety evaluation has been paid great attention both in vitro and in vivo. In this paper, the ultra-small MFe2O4 (M = Fe, Mn, Co) nanoparticles with the average size less than 5 nm were prepared by thermal decomposition method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and vibrating sample magnetometry (VSM). The toxic effect on human lung epithelial A549 cells treated with MFe2O4 nanoparticles at the different concentrations was evaluated in vitro. Mitochondrial function (MTT assay), cellular morphology, reactive oxygen species (ROS), superoxide dismutase (SOD), membrane lipid peroxidation (LPO) and glutathione (GSH) were assessed as toxicity end points. The results showed that the cytotoxicity of ultra-small MFe2O4 nanoparticles was in a dose-and time-dependent manner. Moreover, ultra-small Fe3O4 nanoparticles were found to be nearly non-toxic in A549 cells, while MnFe2O4 nanoparticles exhibited cytotoxic effects, and CoFe2O4 nanoparticles exerted higher cytotoxic effects among the three studied particles at the same concentration.