Investigation of the effect of magnetite iron oxide particles size on cytotoxicity in A549 cell line

Introduction: Magnetite as iron oxide is widely used in various industries, in the pharmaceutical industry in particular where it is used for its magnetic properties. The environmental and occupational exposure to airborne nanoparticles and microparticles of iron oxide compounds have been reported. Since authors have reported contradictory results, the objective of this study was to investigate the effect of particles' size in their toxicities. Methods: The human cell line A(549) was exposed with magnetite iron oxide in two size categories of micro (>= 5 mu m) and nano (<100 nm), with four concentrations of 10, 50, 100, and 250 mu g/ml at two time periods of 24 and 72 h. The cell viability, reactive oxygen species (ROS), changes in mitochondrial membrane potential, and incidence of apoptosis were studied. Results: Nano and micro magnetite particles demonstrated diverse toxicity effects on the A(549) cell line at the 24- and 72-h exposure periods; however, the effects produced were time- and concentration-dependent. Nano magnetite particles produced greater cellular toxicities in forms of decreased viabilities at concentration exposures greater than 50 mu g/ml (p < 0.05), along with increased ROS (p < 0.05), decreased cellular membrane potential (p < 0.05), and reduced rate of apoptosis (p < 0.05). Discussion: The results of this study demonstrated that magnetite iron in nano-range sizes had a greater absorbability for the A(549) cell line compared to micro sizes, and at the same time, nanoparticles were more toxic than microparticles, demonstrating higher production of ROS and decreased viabilities. Considering the greater toxicity of nanoparticles of magnetite iron in this study, thorough precautionary control measures must be taken before they can be used in various industries.