title: Toxicity of Graphene Shells, Graphene Oxide, and Graphene Oxide Paper Evaluated with Escherichia coli Biotests.
abstract: The plate-like graphene shells (GS) produced by an original methane pyrolysis method and their derivatives graphene oxide (GO) and graphene oxide paper (GO-P) were evaluated with luminescent Escherichia coli biotests and additional bacterial-based assays which together revealed the graphene-family nanomaterials' toxicity and bioactivity mechanisms. Bioluminescence inhibition assay, fluorescent two-component staining to evaluate cell membrane permeability, and atomic force microscopy data showed GO expressed bioactivity in aqueous suspension, whereas GS suspensions and the GO-P surface were assessed as nontoxic materials. The mechanism of toxicity of GO was shown not to be associated with oxidative stress in the targeted soxS::lux and katG::lux reporter cells; also, GO did not lead to significant mechanical disruption of treated bacteria with the release of intracellular DNA contents into the environment. The well-coordinated time- and dose-dependent surface charge neutralization and transport and energetic disorders in the Escherichia coli cells suggest direct membrane interaction, internalization, and perturbation (i.e., "membrane stress") as a clue to graphene oxide's mechanism of toxicity.
authors.affiliation: Department of Microbiology, Orenburg State University, Pobedy Avenue 13, Orenburg 460018, Russia.
authors.forename: Ludmila V
authors.initials: LV
authors.lastname: Efremova
authors.affiliation: Department of Microbiology, Orenburg State University, Pobedy Avenue 13, Orenburg 460018, Russia ; Institute of Cellular and Intracellular Symbiosis, RAS, Pionerskaya Street 11, Orenburg 460000, Russia.
authors.forename: Alexey S
authors.initials: AS
authors.lastname: Vasilchenko
authors.affiliation: D. Mendeleyev University of Chemical Technology, Miusskaya Square 9, Moscow 125047, Russia.
authors.forename: Eduard G
authors.initials: EG
authors.lastname: Rakov
authors.affiliation: Department of Microbiology, Orenburg State University, Pobedy Avenue 13, Orenburg 460018, Russia.
authors.forename: Dmitry G
authors.initials: DG
authors.lastname: Deryabin
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects* / Q000648:ultrastructure; D006108:Graphite / Q000633:toxicity*; D018625:Microscopy, Atomic Force; D057145:Nanoshells / Q000633:toxicity*; D049329:Nanostructures / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D010087:Oxides / Q000633:toxicity; D017382:Reactive Oxygen Species
chemical_list: D010087:Oxides; D017382:Reactive Oxygen Species; D006108:Graphite