title: Endocytic mechanisms of graphene oxide nanosheets in osteoblasts, hepatocytes and macrophages.
abstract: Nano-graphene oxide (GO) has attracted great interest in nanomedicine due to its own intrinsic properties and its possible biomedical applications such as drug delivery, tissue engineering and hyperthermia cancer therapy. However, the toxicity of GO nanosheets is not yet well-known and it is necessary to understand its entry mechanisms into mammalian cells in order to avoid cell damage and human toxicity. In the present study, the cellular uptake of pegylated GO nanosheets of ca. 100 nm labeled with fluorescein isothiocyanate (FITC-PEG-GOs) has been evaluated in the presence of eight inhibitors (colchicine, wortmannin, amiloride, cytochalasin B, cytochalasin D, genistein, phenylarsine oxide and chlorpromazine) that specifically affect different endocytosis mechanisms. Three cell types were chosen for this study: human Saos-2 osteoblasts, human HepG2 hepatocytes and murine RAW-264.7 macrophages. The results show that different mechanisms take part in FITC-PEG-GOs uptake, depending on the characteristics of each cell type. However, macropinocytosis seems to be a general internalization process in the three cell lines analyzed. Besides macropinocytosis, FITC-PEG-GOs can enter through pathways dependent on microtubules in Saos-2 osteoblasts, and through clathrin-dependent mechanisms in HepG2 hepatocytes and RAW-264.7 macrophages. HepG2 cells can also phagocytize FITC-PEG-GOs. These findings help to understand the interactions at the interface of GO nanosheets and mammalian cells and must be considered in further studies focused on their use for biomedical applications.
authors: Department of Biochemistry and Molecular Biology I, Faculty of Chemistry, Universidad Complutense , 28040 Madrid, Spain.
authors: Javier
authors: J
authors: Linares
authors: M Concepción
authors: MC
authors: Matesanz
authors: Mercedes
authors: M
authors: Vila
authors: M José
authors: MJ
authors: Feito
authors: Gil
authors: G
authors: Gonçalves
authors: María
authors: M
authors: Vallet-Regí
authors: Paula A A P
authors: PA
authors: Marques
authors: M Teresa
authors: MT
authors: Portolés
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001152:Arsenicals / Q000494:pharmacology; D002478:Cells, Cultured; D003571:Cytochalasin B / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D004705:Endocytosis / Q000187:drug effects; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D019833:Genistein / Q000494:pharmacology; D006108:Graphite / Q000378:metabolism*; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010087:Oxides / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000378:metabolism
chemical_list: D001152:Arsenicals; D010087:Oxides; C029341:oxophenylarsine; D015638:Cytochalasin D; D003571:Cytochalasin B; D011092:Polyethylene Glycols; D006108:Graphite; D000584:Amiloride; D019833:Genistein; D016650:Fluorescein-5-isothiocyanate