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1.
Ecotoxicol Environ Saf ; 192: 110304, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32066006

RESUMO

The environmental release of graphene oxide (GO) will certainly induce the GO exposure to plants. To date, the influence of GO on the intracellular structures and the endophytic bacterial ecology of plants have been rarely reported. In the present study, the rice seedlings were exposed to GO (5 mg/L) under hydroponic condition for fifteen days with periodic stir. The cellular structures damage, GO deposition and oxidative stress were found in rice root after GO exposure. A Illumina analysis based on the bacterial 16 S rRNA gene showed that the richness, evenness and diversity of endophytic bacterial communities of rice root decreased due to GO exposure. The relative abundance of beneficial endophytic bacterial populations decreased after GO exposure. Out of potential phenotypes predicted by BugBase, the relative abundance of Gram negative, stress-tolerant and biofilm-forming phenotypes, presented an increase trend after GO exposure.


Assuntos
Grafite/toxicidade , Microbiota/efeitos dos fármacos , Oryza/microbiologia , Poluentes Químicos da Água/toxicidade , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Endófitos/classificação , Endófitos/efeitos dos fármacos , Endófitos/genética , Endófitos/isolamento & purificação , Grafite/metabolismo , Hidroponia , Oryza/efeitos dos fármacos , Oryza/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Plântula/efeitos dos fármacos , Plântula/metabolismo , Plântula/microbiologia , Poluentes Químicos da Água/metabolismo
2.
Chemosphere ; 247: 125877, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31935578

RESUMO

Boron nitride nanosheets (BN NSs), a novel material with a structure similar to graphene, have attracted much attention due to their extraordinary properties. A deep in vivo study of the toxicity of BN NSs is indispensable, which can help to understand their potential risk and provide useful information for their safe application. However, so far as we know, the systematic in vivo toxicity evaluation of BN NSs hasn't been reported. In this study, silkworm (Bombyx mori) was used as a model to investigate the toxicity of BN NSs, by continuously feeding silkworm larvae with BN NSs at various mass concentrations (1%, 2%, 3%, 4%). The toxicity was evaluated from the levels of animal entirety (mortality, silkworm growth, cocoons and silk properties), tissues (pathological examination) and genes (transcriptomic profiling). The results show that the exposure to BN NSs causes no obvious adverse effects on the growth, silk properties or tissues of silkworm, but the expressions of genes in midgut concerned with some specific functions and pathways are significantly changed, indicating that BN NSs may have potential danger to lead to dysfunction. This study has performed in vivo toxicity evaluation of BN NSs and provided useful safety information for the application of BN NSs.


Assuntos
Bombyx/fisiologia , Compostos de Boro/toxicidade , Nanoestruturas/toxicidade , Animais , Sistema Digestório , Perfilação da Expressão Gênica , Grafite/metabolismo , Larva
3.
Biophys Chem ; 253: 106241, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31398633

RESUMO

Micro graphitic - diamond - multi electrode arrays (µG-D-MEAs) are suitable for measuring multisite quantal dopamine (DA) release from PC12 cells. Following cell stimulation with high extracellular KCl and electrode polarization at +650 mV, amperometric spikes are detected with a mean frequency of 0.60 ±â€¯0.16 Hz. In each recording, simultaneous detection of secretory events is occurred in approximately 50% of the electrodes. Kinetic spike parameters and background noise are preserved among the different electrodes. Comparing the amperometric spikes recorder under control conditions with those recorders from PC12 cells previously incubated for 30 min with the dopamine precursor Levodopa (L-DOPA, 20 µM) it appears that the quantal size of amperometric spikes is increased by 250% and the half-time width (t1/2) by over 120%. On the contrary, L-DOPA has no effect on the frequency of secretory events. Overall, these data demonstrate that the µG-D-MEAs represent a reliable bio-sensor to simultaneously monitor quantal exocytotic events from different cells and in perspective can be exploited as a drug-screening tool.


Assuntos
Técnicas Biossensoriais , Diamante/química , Dopamina/metabolismo , Grafite/química , Animais , Células Cultivadas , Diamante/metabolismo , Dopamina/química , Eletrodos , Grafite/metabolismo , Células PC12 , Tamanho da Partícula , Ratos , Propriedades de Superfície
4.
Anal Chim Acta ; 1079: 103-110, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31387700

RESUMO

Characterization of carbonaceous nanomaterials (CNMs) exposure is a key step and of great importance towards a better understanding of their toxicity and underlying mechanisms. However, it has been bottlenecked for lack of valid methods capable of quantifying cell-associated CNMs. Here, we developed a new economical and convenient method based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) that could accumulate graphene oxide (GO) at the interface between the loading well and the gel. The sharp black band formed there can be digitalized and the intensity quantified, which was proportional to the amount of GO loaded onto the gel. The method has a detection limit of 84.1 ng. We showed that the amount of GO in three different cell models, mouse macrophage cells (Raw264.7), human epithelial cells (A549) and mouse mesenchymal stem cells (MSC), could be accurately quantified by this assay, with the uptake rates decreasing in the order of MSC > Raw264.7 > A549. The results were consistent with the fluorescent imaging on cells exposed to fluorescence-labeled GO and TEM examination on ultrathin cell sections. The surprisingly highest uptake rate of MSC might be due to their abundant intracellular vesicles, which deserves further investigation. The novel method provides a complementary quantitative tool to the use of radioactive markers and fluorescent labeling of carbon nanomaterials and may facilitate the toxicological studies on carbon nanomaterials.


Assuntos
Eletroforese em Gel de Poliacrilamida/métodos , Grafite/análise , Células A549 , Animais , Corantes Fluorescentes/química , Grafite/metabolismo , Humanos , Limite de Detecção , Células-Tronco Mesenquimais , Camundongos , Células RAW 264.7
5.
Environ Int ; 131: 104992, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31288181

RESUMO

The outstanding commercial application potential of graphene oxide (GO) will inevitably lead to its increasing release into the environment, and then affect the environmental behavior and toxicity of conventional pollutants. Interactions between arsenite [As (III)]/arsenate [As (V)] with GO and their combined toxicity to Chlorella pyrenoidosa were investigated. Under abiotic conditions, approximately 42% of the adsorbed As (III) was oxidized by GO with simulated sunlight illumination, which was induced by electron-hole pairs on the surface of GO. Co-exposure with GO greatly enhanced the toxicity of As (III, V) to alga. When adding 10 mg/L GO, the 72 h median effect concentration of As (III) and As (V) to C. pyrendoidosa decreased to 12.7 and 9.4 mg/L from 30.1 and 16.3 mg/L in the As alone treatment, respectively. One possible mechanism by which GO enhanced As toxicity could be that GO decreased the phosphate concentration in the algal medium, and then increased the accumulation of As (V) in algae. In addition, transmission electron microscope (TEM) images demonstrated that GO acted as a carrier for As (III) and As (V) transport into the algal cells. Also, GO induced severe oxidative stress, which could have subsequently compromised important detoxification pathways (e.g., As complexation with glutathione, As methylation, and intracellular As efflux) in the algal cells. Our findings highlight the significant impact of GO on the fate and toxicity of As in the aquatic environment.


Assuntos
Arseniatos/toxicidade , Arsenitos/toxicidade , Chlorella/efeitos dos fármacos , Grafite/toxicidade , Poluentes Químicos da Água/toxicidade , Adsorção , Arseniatos/metabolismo , Arsenitos/metabolismo , Biotransformação , Grafite/metabolismo , Poluentes Químicos da Água/metabolismo
6.
Nanotechnology ; 30(39): 395101, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31239418

RESUMO

Among various nanoparticles tested for pharmacological applications over the recent years, graphene quantum dots (GQDs) seem to be promising candidates for the construction of drug delivery systems due to their superior biophysical and biochemical properties. The subcellular fate of incorporated nanomaterial is decisive for transporting pharmaceuticals into target cells. Therefore a detailed characterization of the uptake of GQDs into different breast cancer models was performed. The demonstrated accumulation inside the endolysosomal system might be the reason for the particles' low toxicity, but has to be overcome for cytosolic or nuclear drug delivery. Furthermore, the penetration of GQDs into precision-cut mammary tumor slices was studied. These constitute a far closer to reality model system than monoclonal cell lines. The constant uptake into the depth of the tissue slices underlines the systems' potential for drug delivery into solid tumors.


Assuntos
Neoplasias da Mama/metabolismo , Grafite/metabolismo , Pontos Quânticos/metabolismo , Neoplasias da Mama/patologia , Células Epiteliais/metabolismo , Grafite/química , Humanos , Nanoestruturas/química , Tamanho da Partícula , Pontos Quânticos/química , Frações Subcelulares/metabolismo , Técnicas de Cultura de Tecidos , Células Tumorais Cultivadas
7.
Colloids Surf B Biointerfaces ; 181: 567-575, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31195312

RESUMO

Artificial nanoenzymes which can overcome some drawbacks of natural enzymes is a challenging topic in the biosensor field. Herein, we demonstrated 5, 10, 15, 20-tetrakis (4-carboxylpheyl)-porphyrin modified magnetic ZnFe2O4 nanoparticles loaded on the surface of reduced graphene oxide (Por-ZnFe2O4/rGO), which exhibited intrinsic peroxidase-like activity and rapidly oxidized the peroxidase substrate 3, 3', 5, 5'-tetramethylbenzidine (TMB) into a blue product (OxTMB) distinguished by naked eyes. Interestingly, by comparative study of different nanomaterials ZnFe2O4 nanoparticles, ZnFe2O4/rGO and Por-ZnFe2O4, Por-ZnFe2O4/rGO was proved to possess the highest peroxidase-like activity. Electron spin resonance (ESR) verified the catalytic activity of Por-ZnFe2O4/rGO for H2O2 was due to hydroxyl radical from decomposition of H2O2. Temperature and pH strongly affected the peroxidase-like activity of Por-ZnFe2O4/rGO nanocomposites. Under optimal conditions (pH = 4, 40 °C), the constructed sensor based on the catalytic activity of the Por-ZnFe2O4/rGO could be conveniently used for colorimetric detection of H2O2 in the range of 0.7-30 µM with the detection limit of 0.54 µM. Moreover, the colorimetric sensor based on Por-ZnFe2O4/rGO exhibited a good linear response to glutathione (GHS) in the range of 2-40 µM with a low detection limit of 0.76 µM. The detection of GHS can be easily realized through the obvious color change by naked eyes without any complicated instrumentation.


Assuntos
Colorimetria , Glutationa/análise , Peróxido de Hidrogênio/análise , Peroxidase/metabolismo , Porfirinas/metabolismo , Compostos Férricos/química , Compostos Férricos/metabolismo , Grafite/química , Grafite/metabolismo , Estrutura Molecular , Óxidos/química , Óxidos/metabolismo , Tamanho da Partícula , Peroxidase/química , Porfirinas/química , Propriedades de Superfície , Compostos de Zinco/química , Compostos de Zinco/metabolismo
8.
Colloids Surf B Biointerfaces ; 181: 539-548, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31185446

RESUMO

The biological synthesis of reduced graphene oxide (rGO) from graphene oxide (GO) is an emerging phenomenon for developing biocompatible nanomaterials for its potential applications in nanomedicine. In this study, we demonstrated a simple, green, and non-toxic method for graphene synthesis using the live biomass of Lysinibacillus sphaericus as the reducing and stabilizing agent under ambient conditions. Ultraviolet-visible spectroscopic analysis confirmed the formation of graphene from GO suspension. X-ray diffraction studies showed the disappearance of the GO peak and the appearance of characteristic graphene broad peak at 2θ = 22.8°. Infrared analysis showed the decrease/disappearance of peaks corresponding to the oxygen-containing functionalities, and appearance of a peak at 1620 cm-1 from unoxidized graphitic domains. Scanning electron microscopic images showed that L. sphaericus-reduced graphene oxide (L-rGO) contains aggregated graphene nanoflakes. Evaluation of the in vitro cytotoxicity of L-rGO nanosheets on human skin fibroblasts using the WST-1 assay did not show any significant effects after 24 h of exposure, which is indicative of biocompatibility. Polyacrylamide hydrogels with L-rGO were synthesized and used as scaffolds to support the growth and proliferation of skin fibroblasts. Cell viability assays and DAPI staining showed proliferation of fibroblasts and exhibited 83% of cell viability even after 28 days. Biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus was enhanced in nanocomposite hydrogels in the presence of 0.25 mg/mL GO and L-rGO in 48 h. Overall, this study showed that microbially-synthesized L-rGO can be used as a dopant in polymeric scaffolds for tissue engineering and highlighted their role in biofilm formation.


Assuntos
Resinas Acrílicas/metabolismo , Bacillaceae/metabolismo , Carbono/metabolismo , Grafite/metabolismo , Hidrogéis/metabolismo , Nanocompostos/química , Pele/metabolismo , Engenharia Tecidual , Resinas Acrílicas/química , Bacillaceae/química , Bacillaceae/crescimento & desenvolvimento , Carbono/química , Sobrevivência Celular/efeitos dos fármacos , Grafite/química , Grafite/farmacologia , Humanos , Hidrogéis/química , Tamanho da Partícula , Pele/química , Propriedades de Superfície
9.
Environ Pollut ; 252(Pt A): 62-73, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31146239

RESUMO

Graphene with atomic layer of sp2-hybridized carbon atoms in a hexagonal structure has attracted multidisciplinary attention since its discovery. Due to the inherent advantages of large specific surface area and abundant functional groups, its derivative graphene oxide (GO) nanomaterials have achieved large-scale development in effective pollution treatment. In the past few years, novel GO-based nanomaterials through coupling with other nanomaterials have been synthesized with significant process and applied for efficient elimination of different kinds of pollutants. This paper aims to summarize recent research results on the excellent removal ability of GO-based nanomaterials for various heavy metal ions in aqueous solutions. The synthesis, adsorption process characteristics and interaction mechanism of the adsorbent are emphasized and discussed. The effects of various environmental conditions are outlined. At last, a brief summary, perspective and outlook are presented. This review is intended to provide some thrilling information for the design and manufacture of GO-based nanomaterials for the elimination of heavy metal ions from wastewater in environmental pollution management.


Assuntos
Grafite/metabolismo , Metais Pesados/análise , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Adsorção , Carbono , Grafite/química , Nanoestruturas/química , Compostos Orgânicos , Águas Residuárias/química , Poluentes Químicos da Água/análise
10.
IET Nanobiotechnol ; 13(2): 202-213, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31051452

RESUMO

For the first time, copper nanoparticles (Cu NPs) superficially deposited on reduced graphene oxide (rGO) using Euphorbia cheiradenia Boiss leaf aqueous media. A beneficial series of analytical methods was used to characterise E. cheiradenia Boiss leaf extract and involved nanostructures. The Cu/rGO nanocomposite (NC) obtained from the conversion of Cu2+ ions to Cu NPs and GO to rGO undergoes the plant extract and used as a heterogeneous and reusable nanocatalyst for the destruction of 4-nitrophenol, rhodamine B, methylene blue, methyl orange and congo red using sodium borohydride at ambient temperature. In addition, Cu/rGO NC has reusability for many times in the reduction reactions with no decreasing of its catalytic capability.


Assuntos
Cobre/química , Euphorbia/química , Grafite/química , Extratos Vegetais/metabolismo , Poluentes da Água , Corantes/análise , Corantes/química , Corantes/metabolismo , Cobre/metabolismo , Grafite/metabolismo , Química Verde , Nanopartículas Metálicas/química , Nitrofenóis/análise , Nitrofenóis/química , Nitrofenóis/metabolismo , Tamanho da Partícula , Processos Fotoquímicos , Extratos Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes da Água/análise , Poluentes da Água/química , Poluentes da Água/metabolismo
11.
Talanta ; 200: 107-114, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31036163

RESUMO

Acetylcholine (ACh) and its precursor choline (Ch) play important roles in many biological processes. It is expected that Alzheimer's disease is occurred due to the reduction in synthesis of ACh. On the other hand, the increase in the level of ACh results in a depression of heart rate and over production of saliva. Therefore, the quantitative determination of Ch and ACh is very important in biological media. In the current work, sensitive and selective biosensors composed of choline oxidase (ChO) and/or acetylcholine esterase (AChE) on graphene oxide-ionic liquid (GO-IL)/ glassy carbon electrode (GCE) hyphenated with anodic differential pulse stripping voltammetry (ADPSV) were firstly established for the determination of ACh and Ch in human serum samples. The molecular bond of ionic liquid 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (AMIM TFSI) with GO was investigated by FT-IR and UV-Vis techniques. Furthermore, the surface topography of ChO/GO-IL and AChE-ChO/GO-IL composites was investigated by SEM and XRD. Then, the electron transfer features of biosensors ChO/GO-IL/GCE and AChE-ChO/GO-IL/GCE were characterized by the electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. The ADPSV was further used for the determination of Ch and ACh. The experimental parameters such as differential pulse working potential, differential pulse scan rate, equilibrium time and long-term stability were further optimized. Detection limits of 0.885 and 1.352 nmol L-1 with excellent linearity (R2 = 0.9996) over the range of 5-1000 nmol L-1 were obtained for Ch and ACh, respectively. The developed analytical methods showed excellent accuracy and precision for the determination of Ch and ACh in human serum samples avoiding their pretreatment or purification.


Assuntos
Acetilcolina/sangue , Técnicas Biossensoriais , Colina/sangue , Técnicas Eletroquímicas , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Oxirredutases do Álcool/química , Oxirredutases do Álcool/metabolismo , Carbono/química , Carbono/metabolismo , Grafite/química , Grafite/metabolismo , Humanos , Líquidos Iônicos/química , Líquidos Iônicos/metabolismo
12.
Chemosphere ; 228: 318-327, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31035170

RESUMO

Due to limited knowledge of graphene nanosheets (GNS) on phyto-biological studies, GNS was sprayed to pepper and eggplants during the seasons 2016 and 2017 at doses 0.1, 0.2 and 0.3 GNS g L-1 to assess their biosafety on leaf ultrastructure and agro-physiological traits. GNS was localized on plastids, cell walls and intercellular spaces of both plants. GNS-sprayed peppers characterized by giant chloroplasts with large starch granules and increment of mitochondrial number adjacent to chloroplasts. Whilst, chloroplast ultrastructure of GNS-treated eggplants appeared to be ellipsoidal-shaped with few normal sized-starch granules compared to control. The localization of GNS inside chloroplast may be activated photosynthetic pigments; thereby stimulation of fructose, sucrose and starch was displayed. The rising of hydrogen peroxide of GNS-treated leaves had beneficial role on triggering the activity of catalase, ascorbate peroxidase, glutathione peroxidase and glutathione-S-transferase. Furthermore, the reduction of hydroxyl radical and superoxide anion reflected the involvement of GNS in induction of antioxidant molecules and superoxide dismutase for modulating cell oxidative status. Thus, the lipid peroxidation and electrolyte leakage of GNS-treated plants were kept below the baseline of water-sprayed plants. Moreover, the promotions of health-promoting secondary metabolites via GNS aerosol were in close association to exacerbation of phenylalanine ammonialyase actvity. This study conclusively demonstrated that GNS did not have cytotoxic properties in pepper and eggplant cells rather healthy growth and promoted yield in the terms of number of branches plant-1, number of fruits plant-1 and fruit yield (ton hectare-1) were the net result of GNS-induced metabolic regulation of the leaves physiological status.


Assuntos
Capsicum/química , Grafite/metabolismo , Nanopartículas/química , Folhas de Planta/ultraestrutura , Solanum melongena/química , Contenção de Riscos Biológicos , Folhas de Planta/química
13.
Artif Cells Nanomed Biotechnol ; 47(1): 822-832, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30873880

RESUMO

Graphene and its derivatives, graphene oxide (GO) and graphene oxide quantum dots (GOQDs), have recently attracted much attention as bioactive factors in differentiating stem cells towards osteoblastic lineage. The stem cells from human exfoliated deciduous teeth (SHEDs) possess the properties of self-renewal, extensive proliferation, and multiple differentiation potential, and have gradually become one of the most promising mesenchymal stem cells (MSCs) in bone tissue engineering. The purpose of this study was to explore the effects of GO and GOQDs on the osteogenic differentiation of SHEDs. In this study, GO and GOQDs facilitated SHED proliferation up to 7 days in vitro at the concentration of 1 µg/ml. Because of their excellent fluorescent properties, GOQD uptake by SHEDs was confirmed and distributed in the SHED cytoplasm. Calcium nodules formation, alkaline phosphatase (ALP) activity, and RNA and protein expression increased significantly in SHEDs treated with osteogenic induction medium containing GOQDs but decreased with osteogenic induction medium containing GO. Interestingly, the Wnt/ß-catenin signaling pathway appeared to be involved in osteogenic differentiation of SHEDs induced with GOQDs. In summary, GO and GOQDs at the concentration of 1 µg/ml promoted SHED proliferation. GOQDs induced the osteogenic differentiation of SHEDs, whilst GO slightly inhibited it.


Assuntos
Grafite/farmacologia , Células-Tronco Mesenquimais/citologia , Osteogênese/efeitos dos fármacos , Pontos Quânticos , Dente Decíduo/citologia , Fosfatase Alcalina/metabolismo , Calcificação Fisiológica/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Citoplasma/metabolismo , Grafite/química , Grafite/metabolismo , Humanos , Células-Tronco Mesenquimais/metabolismo , Pontos Quânticos/química , Pontos Quânticos/metabolismo , Esfoliação de Dente , Via de Sinalização Wnt/efeitos dos fármacos , Via de Sinalização Wnt/genética
14.
Mol Pharm ; 16(5): 1982-1998, 2019 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-30892898

RESUMO

Locating nanomedicines at the active sites plays a pivotal role in the nanoparticle-based cancer therapy field. Herein, a multifunctional nanotherapeutic is designed by using graphene oxide (GO) nanosheets with rich carboxyl groups as the supporter for hyaluronic acid (HA)-methotrexate (MTX) prodrug modification via an adipicdihydrazide cross-linker, achieving synergistic multistage tumor-targeting and combined chemo-photothermal therapy. As a tumor-targeting biomaterial, HA can increase affinity of the nanocarrier toward CD44 receptor for enhanced cellular uptake. MTX, a chemotherapeutic agent, can also serve as a tumor-targeting enhancer toward folate receptor based on its similar structure with folic acid. The prepared nanosystems possess a sheet shape with a dynamic size of approximately 200 nm and pH-responsive drug release. Unexpectedly, the physiological stability of HA-MTX prodrug-decorated GO nanosystems in PBS, serum, and even plasma is more excellent than that of HA-decorated GO nanosystems, while both of them exhibit an enhanced photothermal effect than GO nanosheets. More importantly, because of good blood compatibility as well as reduced undesired interactions with blood components, HA-MTX prodrug-decorated GO nanosystems exhibited remarkably superior accumulation at the tumor sites by passive and active targeting mechanisms, achieving highly effective synergistic chemo-photothermal therapeutic effect upon near-infrared laser irradiation, efficient ablation of tumors, and negligible systemic toxicity. Hence, the HA-MTX prodrug-decorated hybrid nanosystems have a promising potential for synergistic multistage tumor-targeting therapy.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Grafite/química , Nanoconjugados/química , Fotoquimioterapia/métodos , Neoplasias do Colo do Útero/terapia , Adipatos/química , Adipatos/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Sinergismo Farmacológico , Feminino , Grafite/metabolismo , Células HeLa , Humanos , Ácido Hialurônico/química , Ácido Hialurônico/metabolismo , Células MCF-7 , Metotrexato/química , Metotrexato/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Células NIH 3T3 , Pró-Fármacos/química , Pró-Fármacos/metabolismo , Distribuição Tecidual , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Bioresour Technol ; 283: 129-137, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30901585

RESUMO

In this study, reduced graphene oxide (rGO) was developed and employed as cathode catalyst in a membrane-less microbial fuel cell (MFC) to improve energy and metal (copper) recovery in combined with biofilms. Results showed that rGO-based cathode exhibited better characterizations in structure and electron transfer than graphene oxide (GO)-based cathode. The voltage with rGO was about 67% increased, and Cu2+ removal efficiency was 43% improved as compared to GO. Cu species on cathode demonstrated the favorable Cu2+ reduction to Cu with the catalysis of rGO. Moreover, microbial community analysis indicated that rGO-based cathode exhibited better biocompatibility for functional bacteria that related to electron transfer and Cu2+ resistance, such as Geobacter and Pseudomonas, demonstrating the interspecific synergism of microorganisms for efficient energy and copper recovery. It will be of important significance for the heavy metal and energy recovery from low concentrations wastewater by using microbial fuel cell.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Biofilmes , Cobre/metabolismo , Grafite/metabolismo , Biocatálise , Eletrodos , Transporte de Elétrons , Geobacter/fisiologia , Pseudomonas/fisiologia
16.
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
17.
Nano Lett ; 19(2): 1260-1268, 2019 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-30628448

RESUMO

The biological interactions of graphene have been extensively investigated over the last 10 years. However, very little is known about graphene interactions with the cell surface and how the graphene internalization process is driven and mediated by specific recognition sites at the interface with the cell. In this work, we propose a methodology to investigate direct molecular correlations between the biomolecular corona of graphene and specific cell receptors, showing that key protein recognition motifs, presented on the nanomaterial surface, can engage selectively with specific cell receptors. We consider the case of apolipoprotein A-I, found to be very abundant in the graphene protein corona, and observe that the uptake of graphene nanoflakes is somewhat increased in cells with greatly elevated expression of scavenger receptors B1, suggesting a possible mechanism of endogenous interaction. The uptake results, obtained by flow cytometry, have been confirmed using Raman microspectroscopic mapping, exploiting the strong Raman signature of graphene.


Assuntos
Apolipoproteína A-I/metabolismo , Grafite/metabolismo , Nanopartículas/metabolismo , Coroa de Proteína/metabolismo , Receptores Depuradores/metabolismo , Transporte Biológico , Células HEK293 , Humanos , Modelos Moleculares
18.
ACS Sens ; 4(1): 200-210, 2019 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-30596230

RESUMO

Early detection of peptide aggregate intermediates is quite challenging because of their variable and complex nature as well as due to lack of reliable sensors for diagnosis. Herein, we report the detection of monomers and oligomers using specified fluorescence and a magnetic resonance imaging (MRI) multimodal probe based on bovine-serum-albumin-capped fluorine functionalized graphene quantum dots (BSA@FGQDs). This probe enables in vitro fluorescence-based monitoring of human islet amyloid polypeptide (hIAPP), insulin, and amyloid ß(1-42) (Aß42) monomers and oligomers during the fibrillogenesis dynamic. Up to 90% fluorescence quenching of BSA@FGQDs probe upon addition of amyloid monomers/oligomers was observed due to static quenching and nonradiative energy transfer. Moreover, the BSA@FGQDs probe shows 10 times higher signals in detecting amyloid intermediates and fibrils than that of conventional thioflavin dye. A negative Δ G° value (-36.21 kJ/mol) indicates spontaneous interaction of probe with the peptide. These interactions are hydrogen bonding and hydrophobic as proved by thermodynamic parameters. Visual binding clues of BSA@FGQDs with different morphological states of amyloid protein was achieved through electron microscopy. Furthermore, intravenous and intracranial injection of BSA@FGQDs probe in Alzheimer model mice brain enabled in vivo detection of amyloid plaques in live mice brain by 19F MRI through contrast enhancement. Our proposed probe not only effectively monitors in vitro fibrillation kinetics of number of amyloid proteins with higher sensitivity and specificity than thioflavin dye, but also, the presence of a 19F center makes BSA@FGQDs an effective probe as a noninvasive and nonradiative in vivo detection probe for amyloid plaques.


Assuntos
Proteínas Amiloidogênicas/análise , Corantes Fluorescentes/química , Grafite/química , Pontos Quânticos/química , Soroalbumina Bovina/química , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/análise , Peptídeos beta-Amiloides/metabolismo , Proteínas Amiloidogênicas/metabolismo , Animais , Bovinos , Fluorescência , Corantes Fluorescentes/metabolismo , Flúor , Grafite/metabolismo , Humanos , Insulina/análise , Insulina/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/análise , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Imagem por Ressonância Magnética/métodos , Camundongos , Fragmentos de Peptídeos/análise , Fragmentos de Peptídeos/metabolismo , Ligação Proteica , Multimerização Proteica , Pontos Quânticos/metabolismo , Soroalbumina Bovina/metabolismo
19.
Biomater Sci ; 7(4): 1598-1606, 2019 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-30698597

RESUMO

Recently, increased attention has been drawn to application of graphene and its derivatives for construction of biosensors, since they can be used to rapidly detect the presence of bio-analytes. Present paper establishes the preparation of a unique transducer which relies on toluidine blue (TB), absorbed by electrochemically reduced graphene oxide (ERGO) transparent thin film onto the surface of the indium tin-oxide (ITO) glass electrode. The proposed TB/ERGO/ITO electrode shows excellent reversible electro-chemical properties. The novel platform has been explored to fabricate a triglyceride (TG) biosensor via co-immobilizing of lipase (LIP) and glycerol dehydrogenase (GDH) onto TB/ERGO/ITO electrode surface. The fabricated bioelectrode (LIP-GDH/TB/ERGO/ITO) directly oxidizes glycerol (produced by catalytic hydrolysis of tributyrin acting as a model TG) in the presence of GDH. The developed bioelectrode replaces unstable biological irreversible redox mediators NAD+/NADH, involved in the triglyceride breakdown reaction. NADH causes fouling on the bioelectrode surface in bi-enzymatic estimation of TG and reduces the shelf-life of biosensor. Electrochemical response studies carried out using cyclic voltammetry reveal that the fabricated electrode can detect tributyrin in the range of 50-400 mg dL-1 with high sensitivity of 29 pA mg-1 dL, low response time of 12 s, long-term stability and a low apparent Michaelis-Menten constant (Kappm) of 0.18 mM, indicating high enzyme affinity of LIP-GDH/TB/ERGO/ITO bioelectrode towards tributyrin. Furthermore, this modified bioelectrode has been explored for estimation of TG with negligible interference in human serum samples. The proposed bi-enzymatic bioelectrode for TG analysis offers an efficient and novel interface for application of graphene and its derivatives in the field of bioelectronic devices.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Grafite/química , Lipase/metabolismo , Desidrogenase do Álcool de Açúcar/metabolismo , Triglicerídeos/análise , Eletrodos , Grafite/metabolismo , Humanos , Lipase/química , Oxirredução , Tamanho da Partícula , Desidrogenase do Álcool de Açúcar/química , Propriedades de Superfície , Compostos de Estanho/química , Compostos de Estanho/metabolismo , Cloreto de Tolônio/química , Cloreto de Tolônio/metabolismo , Triglicerídeos/metabolismo
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 210: 348-354, 2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30476875

RESUMO

Fluorescence quenching was used to elucidate the binding interaction mechanism between bovine serum albumin (BSA) and graphene oxide (GO). By analyzing the values of Stern-Volmer quenching constant (KSV) and binding constant (KA) which were affected by temperature, we supposed that the quenching process between GO and BSA was mainly determined by static quenching, combined with dynamic quenching. The study of thermodynamics showed that the values of enthalpy change (∆H), entropy change (∆S) and Free Energy (∆G) were all negative, which implied that the weak interaction of the molecular between BSA and GO was Van der Waals interaction or hydrogen bond, and the quenching process was exothermic and spontaneous. The red shift in the synchronous fluorescence spectra suggested that the conformation of tryptophan was changed in the presence of GO. According to Förster's non-radiative energy transfer theory, the distance r between BSA (donor) and GO (acceptor) was calculated and indicated the occurrence of energy transfer from BSA to GO had high probability. The AFM observation and Raman spectroscopy revealed that the interaction between BSA and GO has occurred. Compared with other literatures, the explosion of surface topography about BSA and GO was paid more attention on in this study.


Assuntos
Grafite/química , Soroalbumina Bovina/química , Entropia , Transferência Ressonante de Energia de Fluorescência , Grafite/metabolismo , Ligação de Hidrogênio , Microscopia de Força Atômica , Óxidos , Conformação Proteica , Soroalbumina Bovina/metabolismo , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Análise Espectral Raman , Temperatura , Termodinâmica , Triptofano
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