Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 305
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Chemosphere ; 233: 920-935, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340420

RESUMO

The current study aimed to investigate the impacts of different concentrations of GO/PANI nanocomposites (25, 50 and 100 mg L-1), in comparison with GO and PANI, on seed germination behaviors, morpho-physiological and biochemical traits in intact (mucilaginous) and demucilaged seeds, and young seedlings of the medicinal plant Salvia mirzayanii. Upon exposure to GO, seed germination was delayed and reduced, and growth attributes (root and shoot length, shoot fresh weight, and total chlorophyll content) declined, all of which could be attributed to the reductions in water uptake and oxidative stress particularly in demucilaged seeds. A hormetic dose-dependent response was observed for the growth traits in both intact and demucilaged seedlings upon exposure to GO/PANI concentrations, i.e. low-concentration stimulation and high-concentration repression. Elevated levels of H2O2 in shoot tissue of the seedlings exposed to GO and high concentration of GO/PANI, in comparison with those exposed to low levels of GO/PANI and control, were linked with the activities of the antioxidant enzymes SOD, CAT, POD, and total phenolics. Overall, the results showed high toxicity of GO on germination and early growth of S. mirzayani that was more evident in demucilaged seedlings, whereas GO/PANI stimulated germination, and the effects on seedling growth were stimulatory or inhibitory depending on the application dose and presence of mucilage. Furthermore, the capacity of GO/PANI nanocomposites to improve germination and cause a regular porosity pattern in roots accompanied by improved water uptake and early establishment of S. mirzayanii propose potential implications of GO/PANI nanocomposites for seeds/plants in drought-prone ecosystems.


Assuntos
Compostos de Anilina/toxicidade , Antioxidantes/farmacologia , Germinação/efeitos dos fármacos , Grafite/toxicidade , Salvia/metabolismo , Plântula/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Catalase/metabolismo , Clorofila , Peróxido de Hidrogênio/farmacologia , Nanocompostos , Estresse Oxidativo/efeitos dos fármacos , Mucilagem Vegetal/metabolismo , Superóxido Dismutase/metabolismo , Água
2.
Environ Pollut ; 249: 1106-1114, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31146316

RESUMO

Graphene oxide (GO) has been demonstrated to be key component for diverse applications. However, their potential environmental reactivity, fate and risk have not been fully evaluated to date. In this study, we investigated the photochemical reactivity of four types of GO with different oxidation degrees in aqueous environment, and their related toxicity to two bacterial models Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was further compared. After UV-irradiation, a large amount of oxygen functional groups on GO were reduced and the electronic conjugations within GO were restored as indicated by UV-visible absorption spectra, X-ray photoelectron spectroscopy and Raman spectroscopy analysis. Moreover, the higher the oxidation degree of the pristine GO was, the more obvious of the photo-transformation changes were. In order to further reveal the photochemical reactivity mechanisms, the reactive oxygen species (ROS) generation of GO was monitored. The quantity of ROS including singlet oxygen (1O2), superoxide anions (O2·-), and hydroxyl radicals (·OH) increased with increasing oxidation degree of GO, which was in accordance with the previous characterization results. Scanning electron microscopy and cell growth analyses of E. coli and S. aureus showed that the photochemical transformation enhanced the toxicity of GO, which might be due to an increase in functional group density. The higher conductivity of the reduced graphene oxide (RGO) was responsible for its stronger toxicity than GO through membrane damage and oxidative stress to bacteria. This study revealed that the oxidation degrees play important roles in photochemical transformation and the resulting toxicity of GO, which is helpful for understanding the environmental behaviors and risks of GO in aquatic environments.


Assuntos
Escherichia coli/efeitos dos fármacos , Grafite/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Escherichia coli/crescimento & desenvolvimento , Grafite/efeitos da radiação , Oxirredução , Processos Fotoquímicos , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/crescimento & desenvolvimento , Poluentes Químicos da Água/efeitos da radiação
3.
Int J Nanomedicine ; 14: 3669-3678, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190818

RESUMO

Background: Electrospun gelatin/polycaprolactone (Gt/PCL) nanofibrous scaffolds loaded with graphene are novel nanomaterials with the uniquely strong property of electrical conductivity, which have been widely investigated for their potential applications in cardiovascular tissue engineering, including in bypass tracts for atrioventricular block. Purpose: Electrospun Gt/PCL/graphene nanofibrous mats were successfully produced. Scanning electron micrography showed that the fibers with graphene were smooth and homogeneous. In vitro, to determine the biocompatibility of the scaffolds, hybrid scaffolds with different fractions of graphene were seeded with neonatal rat ventricular myocytes. In vivo, Gt/PCL scaffolds with different concentrations of graphene were implanted into rats for 4, 8 and 12 weeks. Results: CCK-8 assays and histopathological staining (including DAPI, cTNT, and CX43) indicated that cells grew and survived well on the hybrid scaffolds if the mass fraction of graphene was lower than 0.5%. After implanting into rats for 4, 8 or 12 weeks, there was no gathering of inflammatory cells around the nanomaterials according to the HE staining results. Conclusion: The results indicate that Gt/PCL nanofibrous scaffolds loaded with graphene have favorable electrical conductivity and biological properties and may be suitable scaffolds for use in the treatment of atrioventricular block. These findings alleviate safety concerns and provide novel insights into the potential applications of Gt/PCL loaded with graphene, offering a solid foundation for comprehensive in vivo studies.


Assuntos
Gelatina/toxicidade , Grafite/toxicidade , Nanofibras/toxicidade , Poliésteres/toxicidade , Engenharia Tecidual , Tecidos Suporte/química , Testes de Toxicidade , Animais , Apoptose/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Processamento de Imagem Assistida por Computador , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Ratos , Suínos
4.
Ecotoxicol Environ Saf ; 181: 345-352, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31202935

RESUMO

Nanomaterials are being used increasingly in various areas such as electronic devices manufacture, medicine, mechanical devices production, and even food industry. Therefore, the evaluation of their toxicity is mandatory. Graphene oxide (GO) has been shown to have both positive as well as negative impact on different crop plants, depending on species, dose, and duration of exposure. The current study evaluated the impact of GO sheets at different concentrations (500, 1000 and 2000 mg/L) on physiological, biochemical and genetic levels to determine the possible toxic action. Wheat caryopses were treated with GO for 48 h and 7 days. The germination rate and roots elongation decreased in a dose-response manner, except the sample treated with GO at a concentration of 1000 mg/L. Mitotic index has ascendant trend; its increase may be due to the accumulation of prophases GO induced significant accumulation of the cells with aberrations, their presence suggests a clastogenic/aneugenic effect of these carbon nanomaterials. Regarding enzymatic and non-enzymatic antioxidant system defence, the activity varied depending on the dose of GO. Thus, chlorophyll a pigments content decreased significantly at high dose (2000 mg/L), while the carotenoid pigments had lower content at 500 mg/L of GO, and no statistical difference encountered in case of chlorophyll b amount. The antioxidant enzyme activity (CAT, POD, and SOD) was higher at low dose of GO, indicating the presence of oxidative stress generated as a response to the GO treatment. Also, the free radical scavenging activity of the polyphenolic compounds was enhanced upon GO exposure. The GO accumulation has been identified by transmission electron microscopy only at plumules level, near the intercellular space.


Assuntos
Grafite/toxicidade , Nanoestruturas/toxicidade , Triticum/efeitos dos fármacos , Antioxidantes/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Germinação/efeitos dos fármacos , Estresse Oxidativo , Óxidos/toxicidade , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Plântula/efeitos dos fármacos , Plântula/enzimologia , Plântula/metabolismo , Triticum/enzimologia , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
5.
Chem Biol Interact ; 307: 206-222, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31054282

RESUMO

Application of nanomaterials in our daily life is increasing, day in day out and concerns have raised about their toxicity for human and other organisms. In this manner, carbon-based nanomaterials have been applied to different products due to their unique physicochemical, electrical, mechanical properties, and biological compatibility. But, there are several reports about the negative effects of these materials on biological systems and cellular compartments. This review article describes the various types of carbon-based nanomaterials and methods that use for determining these toxic effects that are reported recently in the papers. Then, extensively discussed the toxic effects of these materials on the human and other living organisms and also their toxicity routs including Neurotoxicity, Hepatotoxicity, Nephrotoxicity, Immunotoxicity, Cardiotoxicity, Genotoxicity and epigenetic toxicity, Dermatotoxicity, and Carcinogenicity.


Assuntos
Carbono/química , Nanoestruturas/química , Animais , Sobrevivência Celular/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Fulerenos/química , Fulerenos/toxicidade , Grafite/química , Grafite/toxicidade , Humanos , Nanoestruturas/toxicidade , Nanotubos de Carbono/química , Nanotubos de Carbono/toxicidade , Estresse Oxidativo/efeitos dos fármacos
6.
Environ Sci Pollut Res Int ; 26(19): 19560-19574, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31079296

RESUMO

The current study checks the effect of various concentrations of dietary graphene oxide (GO) nano-sheets on the development of Drosophila melanogaster. GO was synthesized and characterized by XRD, FTIR, FESEM, and TEM analytical techniques. Various concentrations of GO were mixed with the fly food and flies were transferred to the vial. Various behavioral and morphological as well as genetic defects were checked on the different developmental stages of the offspring. In the larval stage of development, the crawling speed and trailing path change significantly than the control. GO induces the generation of oxygen radicals within the larval hemolymph as evidenced by nitroblue tetrazolium assay. GO induces DNA damage within the gut cell, which was detected by Hoechst staining and within hemolymph by comet assay. Adult flies hatched after GO treatment show defective phototaxis and geotaxis behavior. Besides behavior, phenotypic defects were observed in the wing, eye, thorax bristles, and mouth parts. At 300 mg/L concentration, wing spots were observed. Altogether, the current study finds oral administration of GO which acts as a mutagen and causes various behavioral and developmental defects in the offspring. Here for the first time, we are reporting GO, which acts as a teratogen in Drosophila, besides its extensive medical applications.


Assuntos
Drosophila melanogaster/efeitos dos fármacos , Grafite/toxicidade , Mutagênicos/toxicidade , Nanoestruturas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Teratogênios/toxicidade , Administração Oral , Animais , Comportamento Animal/efeitos dos fármacos , Dano ao DNA , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Larva/genética , Larva/crescimento & desenvolvimento
7.
Ecotoxicol Environ Saf ; 180: 269-279, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31100591

RESUMO

With the broad application of nanoparticles, nanotoxicology has attracted substantial attention in environmental science. However, the methods for detecting few and targeted genes or proteins, even single omics approaches, may miss other responses, including the major responses induced by nanoparticles. To determine the actual toxicological mechanisms of zebrafish brains induced by graphene oxide (GO, a popular carbon-based nanomaterial applied in various fields) at nonlethal concentrations, multi-omics and regular analyses were combined. The biomolecule responses were remarkable, although GO was not obviously observed in brain tissues. The trends for gene and protein changes were the same and accounted for 3.53% and 5.36% of all changes in the genome and proteome, respectively, suggesting a limitation of single omics analysis. Transcriptomics and proteomics analyses indicated that GO affected the functions or pathways of the troponin complex, actin cytoskeleton, monosaccharide transmembrane transporter activity, oxidoreductase activity and focal adhesion. Both metabolomics and proteomics revealed mitochondrial dysfunction and disruption of the citric acid cycle. The integrated analysis of omics, transmission electron microscopy and immunostaining confirmed that GO induced energy disruptions and mitochondrial damage by downregulating tubulin. The combination of multi-omics and regular analyses provides insights into the actual and highly influential mechanisms underlying nanotoxicity.


Assuntos
Encéfalo/efeitos dos fármacos , Grafite/toxicidade , Nanopartículas/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/metabolismo , Animais , Encéfalo/metabolismo , Citoesqueleto/metabolismo , Relação Dose-Resposta a Droga , Metabolismo Energético/efeitos dos fármacos , Perfilação da Expressão Gênica/métodos , Metabolômica/métodos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteômica/métodos , Peixe-Zebra/genética
8.
Environ Pollut ; 251: 821-829, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31125812

RESUMO

Currently, there is little comparative data on the colloidal stability and the toxicity of ultraviolet (UV)- and visible-light (VL)-transformed graphene oxide (GO). In order to identify this knowledge gap, the physicochemical properties of UV/VL-transformed GO are investigated in detail. Attempts are made to correlate the physicochemical alterations of UV/VL-transformed GO to the observed changes in its colloidal properties and toxicity. The results show that both UV and VL irradiations induce the significant change in the color, UV-vis absorbance, morphology, surface charge, size, oxygen containing functional groups, total of carbon, and photoluminescence properties of GO. The photo-reaction behavior of GO under UV exposure is different from that under VL irradiation in terms of reaction rate, order, and extent. Finally, the UV and VL irradiations show different effects not only on the colloidal stability of GO in the City water and Dongpu Lake water, but also on the toxicity of GO to Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria. This study clearly shows how the environmental fate and risk of GO are modified by UV and VL irradiations.


Assuntos
Escherichia coli/efeitos dos fármacos , Grafite/química , Grafite/toxicidade , Staphylococcus aureus/efeitos dos fármacos , Raios Ultravioleta , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade , Luz , Compostos Orgânicos/química , Óxidos/química , Água
9.
Sci Total Environ ; 673: 810-820, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31005017

RESUMO

Graphene oxide (GO) has wide engineering applications in various areas, including electronics, energy storage, pharmaceuticals, nanomedicine, environmental remediation and biotechnology, because of its unique physico-chemical properties. In the present study, the risk-related information of GO was evaluated to examine the potential ecological and health risks of developmental toxicity. Although the overall developmental toxicity of GO has been well characterized in zebrafish, however, its release effect at a certain concentration of living organisms with specific cardiovascular defects remains largely elusive. Therefore, this study was conducted to further evaluate the toxicity of GO on embryonic development and cardiovascular defects in zebrafish embryos used as an in-vivo animal model. As a result, the presence of GO at a small concentration (0.1-0.3 mg/mL) does not affect the embryonic development. However, GO at higher concentrations (0.4-1 mg/mL) induces significant embryonic mortality, increase heartbeat, delayed hatching, cardiotoxicity, cardiovascular defects, retardation of cardiac looping, increased apoptosis and decreased hemoglobinization. These results provide valuable information that can be used to study the eco-toxicological effects of GO for assessing its bio-safety according to environmental concentration. In addition, the present results would also be usefully utilized for understanding the environmental risks associated with GO on human health in general.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Grafite/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/embriologia , Animais , Recuperação e Remediação Ambiental , Óxidos/toxicidade
10.
Mar Drugs ; 17(4)2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30987286

RESUMO

Chitin (CT) is a good material to prepare surgical sutures due to its conspicuous biological characteristics. However, the poor mechanical strength of pure CT sutures limits its application. In order to improve its strength, a composite monofilament absorbable suture was prepared in this study using graphene oxide and chitin (GO-CT) using a green method. FT-IR spectra showed that GO-CT contained the characteristic functional groups of GO and CT, indicating that a GO-CT suture was successfully obtained. With the addition of a small amount of GO (1.6wt% solution) in chitin, the breaking tensile strength, knot strength, and knot-pull strength of the GO-CT suture were significantly improved compared to the CT suture. The biocompatibility of the GO-CT suture in vitro was checked by tetrazolium-based colorimetric assays and no cytotoxicity to L929 cells was found. In vivo, the subcutaneous implantation of GO-CT sutures in the dorsal skin of rats found no abnormalities by hematoxylin-eosin staining. Furthermore, there were no significant changes in the gene expression of the inflammatory mediators, interleukin 1ß (IL-1ß), tumor necrosis factor-α, IL-6, IL-17A, interferon-γ, or IL-10; however, the expression of transforming growth factor ß was significantly increased in the first week. In summary, GO-CT sutures may have potential as a suture material in the clinic.


Assuntos
Materiais Biocompatíveis/química , Quitina/química , Grafite/química , Suturas , Animais , Materiais Biocompatíveis/toxicidade , Linhagem Celular , Quitina/toxicidade , Grafite/toxicidade , Teste de Materiais , Camundongos , Modelos Animais , Ratos , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração , Testes de Toxicidade
11.
Chemosphere ; 224: 796-804, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30851531

RESUMO

Rapidly expanding nanoparticle industries are predicted to have turnover of ∼$173.95 billion by 2025, indicating an urgency to study their comprehensive toxicological impact(s). Toxic effects of Graphene Oxide (GO) on oxidative stress physiology especially at mitochondrial level and redox modulation in fish in general and in climbing perch Anabas testudineus is absent. Therefore, we have investigated the toxic impacts of sub lethal doses of GO on selected oxidative stress physiology markers, protein and nucleic acid content along with haematological parameters in A. testudineus. Discriminant function and correlation analyses suggest that GO had toxic effects on the fish, as revealed from the studied parameters. Liver and gill tissues had shown strong response to GO than muscle. Augmented gradual accumulation of cellular lipid peroxides, specifically in mitochondria, was noticed. Activity of superoxide dismutase, catalase, and glutathione-S-transferase was augmented in contrast to the lowered level of the reduced glutathione titre. Alleviated total red blood corpuscle count and haemoglobin titre was parallel with an augmentation of white blood corpuscle count under GO administration. The protein level was also alleviated gradually in liver with clear changes in tissue specific nucleic acid levels, which was reduced under GO treatment. Results of the present study indicate that GO induces oxidative stress in cell and mitochondria in fish. Therefore, very careful future practices of use of GO directly, or as cargo in environmental monitoring processes in aquatic models in vitro in general and Pisces model in particular are suggested.


Assuntos
Grafite/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Mitocôndrias/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Percas/metabolismo , Animais , Catalase/metabolismo , Monitoramento Ambiental , Brânquias/metabolismo , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Transferase/metabolismo , Fígado/metabolismo , Nanopartículas/toxicidade , Oxirredução/efeitos dos fármacos , Alimentos Marinhos , Superóxido Dismutase/metabolismo
12.
J Nanobiotechnology ; 17(1): 32, 2019 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-30797235

RESUMO

BACKGROUND: The conventional approaches to assess the potential cytotoxic effects of nanomaterials (NMs) mainly rely on in vitro biochemical assays. These assays are strongly dependent on the properties of the nanomaterials, for example; specific surface area (SSA), size, surface defects, and surface charge, and the host response. The NMs properties can also interfere with the reagents of the biochemical and optical assays leading to skewed interpretations and ambiguous results related to the NMs toxicity. Here, we proposed a structured approach for cytotoxicity assessment complemented with cells' mechanical responses represented as the variations of elastic Young's modulus in conjunction with conventional biochemical tests. Monitoring the mechanical properties responses at various times allowed understanding the effects of NMs to the filamentous actin cytoskeleton. The elastic Young's modulus was estimated from the force volume maps using an atomic force microscope (AFM). RESULTS: Our results show a significant decrease on Young's modulus, ~ 20%, in cells exposed to low concentrations of graphene flakes (GF), ~ 10% decrease for cells exposed to low concentrations of multiwalled carbon nanotubes (MWCNTs) than the control cells. These considerable changes were directly correlated to the disruption of the cytoskeleton actin fibers. The length of the actin fibers in cells exposed to GF was 50% shorter than the fibers of the cells exposed to MWCNT. Applying both conventional biochemical approach and cells mechanics, we were able to detect differences in the actin networks induced by MWCNT inside the cells and GF outside the cell's membrane. These results contrast with the conventional live/dead assay where we obtained viabilities greater than 80% after 24 h; while the elasticity dramatically decreased suggesting a fast-metabolic stress generation. CONCLUSIONS: We confirmed the production of radical oxygen species (ROS) on cells exposed to CBNs, which is related to the disruption of the cytoskeleton. Altogether, the changes in mechanical properties and the length of F-actin fibers confirmed that disruption of the F-actin cytoskeleton is a major consequence of cellular toxicity. We evidenced the importance of not just nanomaterials properties but also the effect of the location to assess the cytotoxic effects of nanomaterials.


Assuntos
Módulo de Elasticidade/efeitos dos fármacos , Grafite/toxicidade , Nanotubos de Carbono/toxicidade , Células 3T3 , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Adsorção , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/citologia , Camundongos , Tamanho da Partícula , Propriedades de Superfície
13.
Sci Total Environ ; 664: 536-545, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-30759415

RESUMO

The potential adverse effects of graphene quantum dots (GQDs) have increasingly attracted attention. Our present study revealed the genotoxic responses of rat alveolar macrophages (NR8383) to aminated graphene QDs (AG-QDs) and detected the cellular recovery after removing AG-QDs. Global gene expression analysis from RNA-sequencing showed that AG-QDs (100 µg/mL) caused significant alterations in expression of 2898 genes after exposure for 24 h. Among these, 1335 and 1563 genes were up-regulated and down-regulated, respectively. Based on the Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) analysis, we found that most of the down-regulated genes were responsive to "cell cycle", which correlated well with the cell cycle arrest data that AG-QDs triggered cell cycle arrest at S (synthesis) and G2/M (second gap/mitosis) phase. The percentages of cells in S and G2/M phase were increased by 4.5%, and 29.0%, respectively. In addition, the up-regulated genes related with "endocytosis" and "phagocytosis" were identified, which could regulate the internalization of AG-QDs by endocytosis and phagocytosis. After removing exposed AG-QDs and re-incubating the cells in fresh medium, the arrest of S and G2/M phase in NR8383 cells was reduced, and the cell cycle gradually recovered. This cellular recovery could be attributed to the cellular excretion of AG-QDs and the up-regulation of the DNA-repair-related genes (Rad51, Brca2, and Atm). The current work provides insights into the potential hazards of AG-QDs in transcriptional level and presented the long-term effects of AG-QDs on organisms in environment.


Assuntos
Grafite/toxicidade , Pontos Quânticos/toxicidade , Animais , Ciclo Celular , Dano ao DNA , Endocitose , Macrófagos , Testes de Mutagenicidade , Fagocitose , Ratos
14.
Environ Pollut ; 247: 595-606, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30708322

RESUMO

Graphene family nanomaterials (GFNs) have attracted significant attention due to their unique characteristics and applications in the fields of biomedicine and nanotechnology. However, previous studies highlighted the in vitro and in vivo toxicity of GFNs with size and oxidation state differences are still elusive. Therefore, we prepared graphene (G) and graphene oxide (GO) of three different sizes (S-small, M-medium, and L-large), and characterized them using multiple surface-sensitive analytical techniques. In vitro assays using HEK 293T cells revealed that the small and large sizes of G and GO significantly reduced the cell viability and increased DNA damage, accompanying with activated reactive oxygen species (ROS) generation and induced various expressions of associated critical genetic markers. Moreover, the bacterial assays highlighted that G and GO caused strong acute toxicity on Tox2 bacteria. Effects of G were higher than GO and showed size dependent effect: L > M > S, while the medium size of GO induced mild genetic toxicity on RecA bacteria. In vivo assays revealed that exposure to G and GO caused the developmental toxicity, induced ROS generation, and activated related pathways (specifically GO) in zebrafish. Taken together, G showed stronger ability to decrease the survival rate and induce the acute toxicity, while GO showed obvious toxicity in terms of DNA damages, ROS generation, and abnormal gene expressions. Our findings highlighted that G and GO differentially induced toxicity based on their varying physical characteristics, especially sizes and oxidation state, and exposure concentrations and sensitivity of the employed in vitro and in vivo models. In short, this study provided deep insights on the negative effects of GFNs exposure.


Assuntos
Grafite/toxicidade , Nanoestruturas/toxicidade , Óxidos/química , Sobrevivência Celular/efeitos dos fármacos , Dano ao DNA , Proteínas HMGB , Humanos , Oxirredução
15.
Chemosphere ; 223: 157-164, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30776760

RESUMO

Graphene oxide (GO) has been evaluated for application in environmental remediation and pollution control strategies. However, the side effects caused by the interactions of GO with classical pollutants in aquatic environments are still largely unknown. In this work, the ecotoxicological effects of GO, cadmium, zinc and the interactions between GO and these trace elements (co-exposure) were evaluated through acute toxicity tests and routine metabolism (i.e., oxygen consumption and ammonia excretion) in Palaemon pandaliformis (shrimp). After 96 h of exposure, GO did not present acute ecotoxicity at concentrations up to 5.0 mg L-1. However, the association of GO with Cd or Zn increased the toxicity of these trace elements as demonstrated by the decrease in LC50 values. The 96 h LC50 of Cd associated with GO was 1.7 times less than the 96 h LC50 of Cd alone. Similarly, the 96 h LC50 of Zn associated with GO was 1.8 times less than the 96 h LC50 of Zn alone. Additionally, the co-exposure of GO with trace elements impaired the routine metabolism of P. pandaliformis. Finally, the GO potentiated the ecotoxicological effects of Cd and Zn in the shrimp model. Future research on this emerging nanomaterial should focus on its use and disposal in aquatic ecosystems.


Assuntos
Ecotoxicologia/métodos , Grafite/toxicidade , Oligoelementos/toxicidade , Animais , Cádmio , Sinergismo Farmacológico , Dose Letal Mediana , Palaemonidae/metabolismo , Testes de Toxicidade Aguda , Poluentes Químicos da Água/toxicidade , Zinco
16.
Toxicol Ind Health ; 35(1): 79-87, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30803420

RESUMO

Nanomaterials are widely used nowadays in a range of technological and biomedical fields. Graphene as a nanomaterial used in the health-care sector and in workplaces has raised some concerns about its toxicity. This study aimed to evaluate the cytotoxicity of graphene nanoparticles (GNPs) on the A549 epithelial cells of the human lung. The GNPs were synthesized from graphite by the modified Hummer method. The physicochemical characteristics of GNPs were identified by the transmission electron microscope, the scanning electron microscope, and the Brunauer-Emmett-Teller method. The hydrodynamic size of GNPs in the dispersion media was examined using the dynamic light scattering technique. The GNPs were dispersed, after which the A549 cells were cultured. Finally, the cell viability was assayed by the MTT assay. The statistical analysis of variance was used to describe the relationship between the concentration/time variables and the GNP-induced cell deaths. The probit regression model was also used to achieve toxicological indicators. 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-h exposure period compared to a 24-h and 48-h exposure period. The inhibitory concentration of 50% and "no observed adverse effect concentration" were estimated to be 40,653.1 and 0.059 µg/mL, respectively. The results of this study can be helpful in developing the occupational exposure limit for GNPs and in improving occupational health programs in workplaces. However, more investigation is needed to specify the toxicological mechanisms of GNPs.


Assuntos
Grafite/toxicidade , Pulmão/efeitos dos fármacos , Nanopartículas/toxicidade , Mucosa Respiratória/efeitos dos fármacos , Células A549/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Pulmão/citologia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanopartículas/ultraestrutura , Mucosa Respiratória/citologia
17.
Ecotoxicol Environ Saf ; 173: 165-173, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30771660

RESUMO

Graphene oxide (GO) is extensively used in various fields because of its versatility. The presence of GO in the environment enhances the toxicity of toxicants or pollutants. Cadmium (Cd) and GO pollution is a problem in aquatic environment, which should be solved. We investigated the toxic effects of Cd on photosynthesis and oxidative stress in wheat seedlings in the presence of GO, by measuring seedling biomass, Cd content, photosynthesis, reactive oxygen species (ROS) level, antioxidant enzyme activities, and malondialdehyde (MDA) content. At low concentrations, GO alone had limited effects, but at concentrations > 20 mg L-1, seedlings were negatively affected. Under combined Cd-GO treatment, GO was significantly toxic at only 5 mg L-1 concentration, and increasing concentration significantly increased Cd accumulation and decreased biomass. The net photosynthetic rate, stomatal conductance, transpiration rate, primary maximum photochemical efficiency of photosystem II, actual quantum yield, photosynthetic electron transport rate, chlorophyll content, and ribulose-1,5-bisphosphate carboxylase/oxygenase concentration decreased significantly, whereas intercellular CO2 concentration increased significantly. These changes can be attributed to impairment of ROS level, antioxidant enzyme activities, and MDA level, and toxicity mechanisms are suggested to be due to oxidative stress. The resulting damage to the photosynthetic systems and structures likely contributed to the overall decrease in biomass.


Assuntos
Cádmio/metabolismo , Grafite/toxicidade , Fotossíntese/efeitos dos fármacos , Triticum/fisiologia , Poluentes Químicos da Água/toxicidade , Biomassa , Cádmio/química , Cádmio/toxicidade , Grafite/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/fisiologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Triticum/efeitos dos fármacos , Triticum/metabolismo
18.
Int J Hyg Environ Health ; 222(1): 76-83, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30150162

RESUMO

An experimental probabilistic approach for health risk assessment was applied for graphene nanoplatelets (GNPs). The hazard assessment indicated a low level of toxicity for the GNPs. The benchmark dose method, based on sub-chronic and chronic inhalation exposure studies, was used to quantify a guidance value (BMCh) for occupational inhalation exposure to GNPs, expressed as a lognormal distribution with a geometric mean ±â€¯geometric standard deviation of 0.212 ±â€¯7.79 mg/m3 and 9.37 × 104 ±â€¯7.6 particle/cm3. Exposure scenarios (ES) were defined based on the scientific literature for large-scale production (ES1) and manufacturing (ES2) of GNPs; a third ES, concerning in-lab handling of GNPs (ES3) was based on results of experiments performed for this study. A probability distribution function was then assumed for each ES. The risk magnitude was calculated using a risk characterization ratio (RCR), defined as the ratio of the exposure distributions and the BMCh distribution. All three ES resulted in RCR distributions ≥1 (i.e. risk present); however, none of the ES had a statistically significant level of risk at a 95% confidence interval. A sensitivity analysis indicated that ∼75% of the variation in the RCR distributions was due to uncertainties in the BMCh calculation.


Assuntos
Grafite/toxicidade , Nanoestruturas/efeitos adversos , Exposição Ocupacional/efeitos adversos , Relação Dose-Resposta a Droga , Humanos , Modelos Estatísticos , Medição de Risco
19.
Anal Chim Acta ; 1047: 197-207, 2019 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-30567650

RESUMO

This study introduces a new strategy for periodic stacking of positively charged NiAl layered double hydroxides (LDHs) nanosheets with negatively charged monolayers of graphene (G) by systematically optimizing several parameters in a controlled co-feeding fashion and resultant heterostacked NiAl LDH/G LBL nanocomposites have been practically applied in sensitive detection of dopamine released from live cells as early Parkinson's disease (PD) diagnostic tool. PD is the second most chronic neurodegenerative disorder with gradual progressive loss of movement and muscle control causing substantial disability and threatening the life seriously. Unfortunately majority of dopaminergic neurons present in substantia nigra of PD patients are destroyed before it is being clinically diagnosed, so early stages PD diagnosis is essential. Because of direct neighboring of extremely conductive graphene to semiconductive LDHs layers, enhanced intercalation capability of LDHs, and huge surface area with numerous active sites, good synergy effect is harvested in heteroassembled NiAl LDH/G LBL material, which in turn shows admirable electrocatalytic ability in DA detection. The interference induced by UA and AA is effectively eliminated especially after the modifying the electrode with Nafion. The outstanding electrochemical sensing performance of NiAl LDH/G LBL modified electrode has been achieved in terms of broad linear range and lowest real detection limit of 2 nM (S/N = 3) towards DA oxidation. Benefitting from superior efficiency, biosensor has been successfully used for real-time in-vitro tracking of DA efflux from live human nerve cell after being stimulated. We believe that our biosensing platform of structurally integrated well-ordered LBL heteroassembly by inserting graphene directly to the interlayer galleries of LDHs material will open up new avenue in diseases determination window.


Assuntos
Dopamina/análise , Grafite/química , Nanocompostos/química , Hidróxido de Alumínio/síntese química , Hidróxido de Alumínio/química , Hidróxido de Alumínio/toxicidade , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Linhagem Celular Tumoral , Técnicas Eletroquímicas/métodos , Eletrodos , Grafite/síntese química , Grafite/toxicidade , Humanos , Hidróxidos/síntese química , Hidróxidos/química , Hidróxidos/toxicidade , Limite de Detecção , Nanocompostos/toxicidade , Níquel/química , Níquel/toxicidade , Eletricidade Estática
20.
Int J Environ Health Res ; 29(1): 1-21, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30084259

RESUMO

Graphene alone, in modified form or its composites had find their explicit position in the field of adsorption technology and hence assist in detection and removal of heavy metals like Cd (permissible limit 0.1 mg/L), which can cause various physiological problems if entered in variety of biota. Attributed to their unique physiognomies graphene-based adsorbent had classed themselves superior as compared to other carbonaceous adsorbent like CNT's or activated carbon, etc. This assessment summarizes the validity of graphene and its composite as a superior adsorbent for decontamination of Cd from aqueous environment; in addition, this evaluation also pronounces the toxicity profile of trace graphene and necessity of regeneration of the adsorbent.


Assuntos
Cádmio/química , Grafite/química , Poluentes Químicos da Água/química , Adsorção , Animais , Cádmio/análise , Cádmio/toxicidade , Intoxicação por Cádmio , Reutilização de Equipamento , Grafite/toxicidade , Humanos , Modelos Teóricos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA