Nafiseh nasirzadeh - MSC Occupational Health and Safety, health student research committee, faculty of health, Tabriz university of medical sciences, department of public health, Tabriz, Iran
Yahya rasoulzadeh - Ph.D. Occupational Health and Safety, health student research committee, faculty of health, Tabriz university of medical sciences, department of public health, Tabriz, Iran
mansour rezazadeh azari - Ph.D. Occupational Health and Safety, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Introduction:Recently, nanomaterials are widely used in the field of technology and medical science. So that, everybody may be exposed to nanomaterials in the everywhere. The physicochemical properties of nanomaterials have influenced the toxicity and penetration of them into cells. Graphite is one of the nanomaterials which are used in healthcare and workplaces. This study aimed to evaluate the cytotoxicity of Graphite nanoparticles (GrNPs) on A549 epithelial cells of human lung and provide basic data for developing OELs.Method and materials:The physicochemical characteristics of GrNPs were identified by transmission electron microscope, scanning electron microscope and BET method. Hydrodynamic size of GrNPs in dispersion media was examined by using the dynamic light scattering (DLS) technique. GRNPs were dispersed in ethanol and bovine serum albumin water (BSA-water). A549 epithelial cells were cultured in media containing 5% serum. Then, the cells were exposed for 24-hr and 72-hr to between 0.1μg/ml and 500 μg/ml of GrNPs in cutler medium. Cells viability studied by using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Finally, Statistical T-test was used for describing the relationship between concentration/time variables and GrNPs -induced death cells. Probit regression model was also used to achieve toxicology indicators.Results:GrNPs had the average diameter of 20nm. The results showed that the toxicology effects of GrNPs on A549 epithelial cells of human lung are dose-time related (p=0≤0.01). NOAEC and IC50 were obtained 2.35 μg/mL and 273.5 μg/mL respectively at 24-hr. The almost of same results were showed in the lowest concentration of 100 μg/mL from 24-hr to 72-hr.Conclusion:The results of this study can be helpful in developing the occupational exposure limits (OEL) for GrNPs and improving of occupational health programs at workplaces. However, the toxicology of GrNPs were almost neglected and there were a few studies in this case. Therefore, more investigations are still required to clear and specify the toxicological mechanisms of GrNPs.

Nanomaterials, Graphite nanoparticles, Cytotoxicity, Exposures, MTT, IC50