Assessment of cytotoxicity of graphene nanoparticles in epithelial cells of human lunge in an in vitro study and toxicological analysis of occupational exposures

Abstract

Introduction: Nanomaterials are widely used nowadays in a range of technological and biomedical fields. Hence, people can be exposed to nanomaterials just about anywhere. However, the physicochemical properties of nanomaterials influence toxicity, which has an effect on cells. Graphene is a nanomaterial that is used in the healthcare sector and in workplaces. Therefore, this study aimed to evaluate the cytotoxicity of graphene nanoparticles (GNPs) on the A549 epithelial cells of the human lung and to provide basic data for developing the occupational exposure limits (OEL). Method and Materials: The physicochemical characteristics of GNPs were identified by the transmission electron microscope (TEM), the scanning electron microscope (SEM), and the Brunauer-Emmett-Teller (BET) method. The hydrodynamic size of GNPs in the dispersion media was examined using the dynamic light scattering (DLS) technique. The GNPs were dispersed, after which the A549 cells were cultured. Finally, the cytotoxicity of GNPs was assayed by the MTT assay, which is a colorimetric assay in 24, 48 and 72 hours after the exposure with different concentration of GNPs. The toxicological indicators was estimated by probit regression model in Minitabe-18 software. The statistical ANOVA was used to describe the relationship between the concentration/time variables and the GNPinduced cell deaths. Results: The results showed that the toxicological effects of GNPs on the A549 epithelial cells of the human lung are dose- and time-dependent. The GNPs were more cytotoxic after a 72-hour exposure period compared to a 24-hour and 48-hour exposure periods. The IC50 and ‘no observed adverse effect concentration’ (NOAEC) were estimated to be 40.653.1 mg/mL and 0.059 μg/mL, respectively . Discussion: The results of this study can be helpful in developing the OEL for GNPs, where organizations such as NIOSH are trying to develop the standards, and it can be improved occupational health programs in workplaces. However, more investigation is needed to specify the toxicological mechanisms of GNPs.