Cytotoxicity Effects of Graphene and Single-Wall Carbon Nanotubes in Neural Phaeochromocytoma-Derived PC12 Cells

Neurochemistry Laboratory, Division of Neurotoxicology, National Center for Toxicological Research, Food and Drug Administration, 3900 NCTR Road, Jefferson, Arkansas 72079, USA.
ACS Nano (Impact Factor: 12.88). 06/2010; 4(6):3181-6. DOI: 10.1021/nn1007176
Source: PubMed


Graphitic nanomaterials such as graphene layers (G) and single-wall carbon nanotubes (SWCNT) are potential candidates in a large number of biomedical applications. However, little is known about the effects of these nanomaterials on biological systems. Here we show that the shape of these materials is directly related to their induced cellular toxicity. Both G and SWCNT induce cytotoxic effects, and these effects are concentration- and shape-dependent. Interestingly, at low concentrations, G induced stronger metabolic activity than SWCNT, a trend that reversed at higher concentrations. Lactate dehydrogenase levels were found to be significantly higher for SWCNT as compared to the G samples. Moreover, reactive oxygen species were generated in a concentration- and time-dependent manner after exposure to G, indicating an oxidative stress mechanism. Furthermore, time-dependent caspase 3 activation after exposure to G (10 microg/mL) shows evidence of apoptosis. Altogether these studies suggest different biological activities of the graphitic nanomaterials, with the shape playing a primary role.

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    • "A number of studies performed with CNTs have evaluated their toxicity to different organs, such as the lungs, kidneys, and liver (Awasthi et al., 2013; Deng et al., 2009; Li et al., 2007). Several in vitro studies have confirmed that CNTs could generate neurotoxic effects, including decreasing cell activity (Belyanskaya et al., 2009; Zhang et al., 2010). In addition, our previous studies have showed that MWCNTs induce cytotoxicity in C6 cells (Han et al., 2012) and inhibit CA1 glutamatergic synaptic transmission in rat hippocampal slices in vitro (Chen et al., 2014). "
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    ABSTRACT: Multi-walled carbon nanotubes (MWCNTs) have shown potential applications in many fields, especially in the field of biomedicine. Several studies have reported that MWCNTs induce apoptosis and oxidative damage in nerve cells during in vitro experiments. However, there are few studies focused on the neurotoxicity of MWCNTs used in vivo. Many studies have reported that autophagy, a cellular stress response to degrade damaged cell components, can be activated by diverse nanoparticles. In this study, we investigated the neurotoxic effects of MWCNTs on hippocampal synaptic plasticity and spatial cognition in rats. Then, we used an inhibitor of autophagy called chloroquine (CQ) to examine whether autophagy plays an important role in hippocampal synaptic plasticity, since this was damaged by MWCNTs. In this study, adult male Wister rats were randomly divided into three groups: a control group, a group treated with MWCNTs (2.5mg/kg/day) and a group treated with MWCNTs+CQ (20mg/kg/day). After two-weeks of intraperitoneal (i.p.) injections, rats were subjected to the Morris water maze (MWM) test, and the long-term potentiation (LTP) and other biochemical parameters were determined. Results showed that MWCNTs could induce cognitive deficits, histopathological alteration and changes of autophagy level (increased the ratio of LC3 II /LC3 I and the expression of Beclin-1). Furthermore, we found that CQ could suppress MWCNTs-induced autophagic flux and partly rescue the synapse deficits, which occurred with the down-regulation of NR2B (a subunit of NMDA receptor) and synaptophysin (SYP) in the hippocampus. Our results suggest that MWCNTs could induce cognitive deficits in vivo via the increased autophagic levels, and provide a potential strategy to avoid the adverse effects of MWCNTs. Copyright © 2015. Published by Elsevier Ireland Ltd.
    Toxicology 08/2015; 337. DOI:10.1016/j.tox.2015.08.011 · 3.62 Impact Factor
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    • "Concerning the cytotoxic effects of graphene on cells, dose-dependent cytotoxicity of graphene in human erythrocytes and skin fibroblasts was studied by Liao et al. [21]. In addition, dose-and timedependent cytotoxicity of graphene and graphene oxide (GO) on neural pheochromocytoma-derived PC12 [22], A549 [23], and human mesenchymal stem cells (hMSCs) [24] were investigated and the main mechanism of cytotoxicity was assigned to the generation of reactive oxygen species (ROS). The cell membrane damage induced by physically interaction of the cells with the extremely sharp edges of GO [25] [26], change in the chemical state of GO sheets into reduced graphene oxide (rGO) ones under metabolic activity of microorganisms [27] and entrapping microorganisms by aggregating the rGO sheets in a suspension [28] have also been proposed as other mechanisms of cytotoxicity. "
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    ABSTRACT: In vivo dose-dependent effects of nanoscale graphene oxide (NGO) sheets on reproduction capability of Balb/C mice were investigated. Biodistribution study of the NGO sheets (intravenously injected into male mice at dose of ∼2000 μg/mL or 4 mg/kg of body weight) showed a high graphene uptake in testis. Hence, in vivo effects of the NGO sheets on important characteristics of spermatozoa (including their viability, morphology, kinetics, DNA damage and chromosomal aberration) were evaluated. Significant in vivo effects was found at the injected concentrations ≥200 μg/mL after (e.g., ∼45% reduction in sperm viability and motility at 2000 μg/mL). Observation of remarkable DNA fragmentations and chromosomal aberrations of the spermatozoa after ∼8 weeks from the first weekly injection were assigned to the involvement of the NGO in spermatogenesis of the mice. The uptake of the NGO in the testis could also increase the generation of reactive oxygen species in semen of the mice. Moreover, semen of the NGO-treated mice (containing the damaged spermatozoa) might disturb the hormone secretion and pregnant functionality of female mice (∼44, 35 and 59% reduction in fertility, gestation ability and multi-production capability) and also viability of the next generation (∼15% reduction in postnatal viability of delivered pups).
    • "In parallel to efforts directed at identifying new applications for carbon nanotubes (CNTs) and at improving ways to mass-produce them [1] [2], efforts are underway to examine health and ecological effects of these materials, as increasing production and use certainly will lead to release to the environment and biological exposure [3] [4] [5]. Of the several proposed processes used to explain toxicity of these materials, ''oxidative stress'' is recognized as one of the likely causes [6] [7] [8] [9] [10]. Oxidative stress presumably occurs through reactive oxygen species (ROS) generation, and while mechanisms of photo-induced ROS generation by CNTs has been reported [11] [12] [13], there is limited information on light-independent generation of ROS and the underlying mechanisms responsible for this generation [14]. "
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    ABSTRACT: Although induction of oxidative stress is widely accepted as one of the major cytotoxic effects of carbon nanotubes (CNTs), there is no solid understanding of how biological redox reactions are affected and how reactive oxygen species (ROS) are generated by CNTs, especially when they are coated with various dispersing agents. In this study, we investigated electron transfer from biological reducing agents through nonfunctionalized single-walled carbon nanotubes (SWCNTs) to molecular oxygen, generating ROS in the process. Electron transfer rates in the colloidal SWCNT suspensions depended on the dispersant used to stabilize them, with six dispersants examined. Oxidation of both nicotinamide adenine dinucleotide (NADH) and dithiothreitol was catalyzed by SWCNTs coated with either cetyltrimethylammonium bromide (CTAB) or Suwannee River natural organic matter (SRNOM). SWCNTs coated with other types of surfactants showed only slight effect. In the presence of NADH or dithiothreitol, generation of ROS also was dispersant-dependent, with CTAB- and SRNOM-coated SWCNTs generating significant amounts of superoxide anion and hydrogen peroxide. In systems containing xanthine and xanthine oxidase, accumulated charge on the SWCNTs appeared to be transferred to superoxide anion, resulting in indirect disproportionation of superoxide anion, forming more hydrogen peroxide.
    Carbon 08/2015; 89:361-371. DOI:10.1016/j.carbon.2015.03.052 · 6.20 Impact Factor
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