title: Screening of toxic potential of graphene family nanomaterials using in vitro and alternative in vivo toxicity testing systems.
abstract: OBJECTIVE
  The widely promising applications of graphene nanomaterials raise considerable concerns regarding their environmental and human health risk assessment. The aim of the current study was to evaluate the toxicity profiling of graphene family nananomaterials (GFNs) in alternative in vitro and in vivo toxicity testing models.
  
  
  METHODS
  The GFNs used in this study are graphene nanoplatelets ([GNPs]-pristine, carboxylate [COOH] and amide [NH2]) and graphene oxides (single layer [SLGO] and few layers [FLGO]). The human bronchial epithelial cells (Beas2B cells) as in vitro system and the nematode Caenorhabditis elegans as in vivo system were used to profile the toxicity response of GFNs. Cytotoxicity assays, colony formation assay for cellular toxicity and reproduction potentiality in C. elegans were used as end points to evaluate the GFNs' toxicity.
  
  
  RESULTS
  In general, GNPs exhibited higher toxicity than GOs in Beas2B cells, and among the GNPs the order of toxicity was pristine>NH2>COOH. Although the order of toxicity of the GNPs was maintained in C. elegans reproductive toxicity, but GOs were found to be more toxic in the worms than GNPs. In both systems, SLGO exhibited profoundly greater dose dependency than FLGO. The possible reason of their differential toxicity lay in their distinctive physicochemical characteristics and agglomeration behavior in the exposure media.
  
  
  CONCLUSIONS
  The present study revealed that the toxicity of GFNs is dependent on the graphene nanomaterial's physical forms, surface functionalizations, number of layers, dose, time of exposure and obviously, on the alternative model systems used for toxicity assessment.
authors.affiliation: School of Environmental Engineering, Graduate School of Energy and Environmental System Engineering, University of Seoul, Seoul, Korea.
authors.forename: Nivedita
authors.initials: N
authors.lastname: Chatterjee
authors.affiliation: School of Environmental Engineering, Graduate School of Energy and Environmental System Engineering, University of Seoul, Seoul, Korea.
authors.forename: Ji Su
authors.initials: JS
authors.lastname: Yang
authors.affiliation: College of Pharmacy, Dongduk Women's University, Seoul, Korea.
authors.forename: Kwangsik
authors.initials: K
authors.lastname: Park
authors.affiliation: Fusion Technology Laboratory, Hoseo University, Asan, Korea.
authors.forename: Seung Min
authors.initials: SM
authors.lastname: Oh
authors.affiliation: Korea Environmental Institute, Seoul, Korea.
authors.forename: Jeonggue
authors.initials: J
authors.lastname: Park
authors.affiliation: School of Environmental Engineering, Graduate School of Energy and Environmental System Engineering, University of Seoul, Seoul, Korea.
authors.forename: Jinhee
authors.initials: J
authors.lastname: Choi
keywords: Alternative toxicity testing; Caenorhabditis elegans; Graphene family nanomaterials; Human bronchial epithelial cells