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1.
Proc Natl Acad Sci U S A ; 119(19): e2106965119, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35522709

RESUMO

SignificanceUnderstanding how protein scaffolds direct mineral morphogenesis is crucial for engineering bone and tooth and would open new vistas in materials design. In the case of tooth enamel, which is the hardest tissue in the body and consists of organized bundles of coaligned apatite crystals, amyloid-like amelogenin nanoribbons are hypothesized to provide the scaffold. We show that these nanoribbons are far more potent calcium phosphate nucleators than other amelogenin motifs or collagen, which provides the scaffold for bone. This potency stems from a periodic array of charged sites that provide a template for calcium phosphate ion binding on a low-energy interface. The ubiquity of ß-sheet protein structures suggests that this mechanism can be adopted for the design of synthetic mineralization-directing scaffolds.


Assuntos
Proteínas do Esmalte Dentário , Nanotubos de Carbono , Amelogenina/química , Proteínas Amiloidogênicas , Sítios de Ligação , Fosfatos de Cálcio
2.
Anal Chim Acta ; 1208: 339851, 2022 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-35525595

RESUMO

We have designed and prepared an electrochemical biosensor for lactate determination. Through a diazotation process, the enzyme lactate oxidase (LOx) is anchored onto chevron-like graphene nanoribbons (GNR), previously synthesized by a solution-based chemical route, and used as modifiers of glassy carbon electrodes. In a first step, we have performed the grafting of a 4-carboxyphenyl film, by electrochemical reduction of the corresponding 4-carboxyphenyl diazonium salt, on the GNR-modified electrode surface. In this way, the carboxylic groups are exposed to the solution, enabling the covalent immobilization of the enzyme through the formation of an amide bond between these carboxylic groups and the amine groups of the enzyme. The biosensor design was optimized through the morphological and electrochemical characterization of each construction step by atomic force microscopy, scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy.The cyclic voltammetric response of the biosensor in a solution of hydroxymethylferrocene in presence of l-lactate evidenced a clear electrocatalytic effect powered by the specific design of the biosensing platform with LOx covalently attached to the GNR layer. From the calibration procedures employed for l-lactate determination, a linear concentration range of 3.4 · 10-5- 2.8 · 10-4 M and a detection limit of 11 µM were obtained, with relative errors and relative standard deviations less than 6.0% and 8.4%, respectively. The applicability of the biosensor was tested by determining lactate in apple juices, leading to results that are in good agreement with those obtained with a well-established enzymatic spectrophotometric assay kit.


Assuntos
Técnicas Biossensoriais , Grafite , Nanotubos de Carbono , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Eletrodos , Enzimas Imobilizadas/química , Grafite/química , Ácido Láctico , Oxigenases de Função Mista , Nanotubos de Carbono/química
3.
Int J Mol Sci ; 23(8)2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35456898

RESUMO

CRISPR-Cas gene editing technologies offer the potential to modify crops precisely; however, in vitro plant transformation and regeneration techniques present a bottleneck due to the lengthy and genotype-specific tissue culture process. Ideally, in planta transformation can bypass tissue culture and directly lead to transformed plants, but efficient in planta delivery and transformation remains a challenge. This study investigates transformation methods that have the potential to directly alter germline cells, eliminating the challenge of in vitro plant regeneration. Recent studies have demonstrated that carbon nanotubes (CNTs) loaded with plasmid DNA can diffuse through plant cell walls, facilitating transient expression of foreign genetic elements in plant tissues. To test if this approach is a viable technique for in planta transformation, CNT-mediated plasmid DNA delivery into rice tissues was performed using leaf and excised-embryo infiltration with reporter genes. Quantitative and qualitative data indicate that CNTs facilitate plasmid DNA delivery in rice leaf and embryo tissues, resulting in transient GFP, YFP, and GUS expression. Experiments were also initiated with CRISPR-Cas vectors targeting the phytoene desaturase (PDS) gene for CNT delivery into mature embryos to create heritable genetic edits. Overall, the results suggest that CNT-based delivery of plasmid DNA appears promising for in planta transformation, and further optimization can enable high-throughput gene editing to accelerate functional genomics and crop improvement activities.


Assuntos
Nanotubos de Carbono , Oryza , Sistemas CRISPR-Cas/genética , DNA , Edição de Genes/métodos , Genoma de Planta , Oryza/genética , Folhas de Planta/genética , Plantas/genética , Plantas Geneticamente Modificadas/genética , Plasmídeos/genética , Sementes/genética
4.
Int J Mol Sci ; 23(8)2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35457058

RESUMO

Carbon nanotubes (CNTs) are carbon allotropes consisting of one, two, or more concentric rolled graphene layers. These can intrinsically regulate immunity by activating the innate immune system. Mannose receptors (MR), a subgroup of the C-type lectin superfamily, are abundantly expressed on macrophages and dendritic cells. These play a crucial role in identifying pathogens, presenting antigens, and maintaining internal environmental stability. Utilizing the specific recognition between mannose and antigen-presenting cells (APC) surface mannose receptors, the antigen-carrying capacity of mannose-modified CNTs can be improved. Accordingly, here, we synthesized the mannose-modified carbon nanotubes (M-MWCNT) and evaluated them as an antigen delivery system through a series of in vitro and in vivo experiments. In vitro, M-MWCNT carrying large amounts of OVA were rapidly phagocytized by macrophages and promoted macrophage proliferation to facilitate cytokines (IL-1ß, IL-6) secretion. In vivo, in mice, M-MWCNT induced the maturation of dendritic cells and increased the levels of antigen-specific antibodies (IgG, IgG1, IgG2a, IgG2b), and cytokines (IFN-γ, IL-6). Taken together, M-MWCNT could induce both humoral and cellular immune responses and thereby can be utilized as an efficient antigen-targeted delivery system.


Assuntos
Nanotubos de Carbono , Animais , Antígenos , Citocinas , Imunidade Celular , Imunoglobulina G , Interleucina-6 , Manose , Camundongos
5.
J Hazard Mater ; 431: 128613, 2022 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-35359102

RESUMO

Agricultural soils are exposed to multiple contaminants through the use of agrochemicals or sewage sludge, introducing metals, nanomaterials and others. Among nanomaterials, carbon nanotubes (CNTs) are known for their large surface area and adsorption capabilities, possibly modifying other element behavior. However, to date, very little is known about the impacts of such interactions in agrosystems. In this study, we aimed at understanding the transfer and toxicity of contaminants (Cd, Pb, Zn and CNTs) in microcosms including native soil bacteria, earthworms and lettuce. After a 6 week exposure, no effect of the addition of CNTs to metal contaminated soils was detected on bacterial concentration or earthworm growth. However, in lettuce, an interactive effect between CNTs and metals was highlighted: in the soil containing the highest metal concentrations the addition of 0.1 mg kg-1 CNTs led to a biomass loss (-22%) and a flavonoid concentration increase (+27%). In parallel, the addition of CNTs led to differential impacts on elemental uptake in lettuce leaves possibly related to the soil organic matter content. For earthworms, the addition of 10 mg kg-1 CNTs resulted in an increased body elemental transfer in the soil with the higher organic matter content (Pb: + 34% and Zn: + 25%).


Assuntos
Nanotubos de Carbono , Oligoquetos , Poluentes do Solo , Animais , Metais/toxicidade , Nanotubos de Carbono/toxicidade , Solo/química , Poluentes do Solo/análise
6.
Int J Mol Sci ; 23(7)2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35409224

RESUMO

In nature, solar energy is captured by different types of light harvesting protein-pigment complexes. Two of these photoactivatable proteins are bacteriorhodopsin (bR), which utilizes a retinal moiety to function as a proton pump, and photosystem I (PSI), which uses a chlorophyll antenna to catalyze unidirectional electron transfer. Both PSI and bR are well characterized biochemically and have been integrated into solar photovoltaic (PV) devices built from sustainable materials. Both PSI and bR are some of the best performing photosensitizers in the bio-sensitized PV field, yet relatively little attention has been devoted to the development of more sustainable, biocompatible alternative counter electrodes and electrolytes for bio-sensitized solar cells. Careful selection of the electrolyte and counter electrode components is critical to designing bio-sensitized solar cells with more sustainable materials and improved device performance. This work explores the use of poly (3,4-ethylenedioxythiophene) (PEDOT) modified with multi-walled carbon nanotubes (PEDOT/CNT) as counter electrodes and aqueous-soluble bipyridine cobaltII/III complexes as direct redox mediators for both PSI and bR devices. We report a unique counter electrode and redox mediator system that can perform remarkably well for both bio-photosensitizers that have independently evolved over millions of years. The compatibility of disparate proteins with common mediators and counter electrodes may further the improvement of bio-sensitized PV design in a way that is more universally biocompatible for device outputs and longevity.


Assuntos
Bacteriorodopsinas , Nanotubos de Carbono , Compostos Bicíclicos Heterocíclicos com Pontes , Cobalto , Eletrodos , Eletrólitos , Nanotubos de Carbono/química , Fármacos Fotossensibilizantes , Complexo de Proteína do Fotossistema I , Polímeros
7.
Se Pu ; 40(5): 469-476, 2022 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-35478006

RESUMO

A modified QuEChERS method, based on multi-walled carbon nanotubes (MWCNTs), was established for the detection of 10 pyrethroid pesticides (cyfluthrin, flucythrinate, fenpropathrin, bifenthrin, cyhalothrin, permethrin, cypermethrin, etofenprox, fenvalerate, deltamethrin) in tea, in combination with gas chromatography-tandem mass spectrometry (GC-MS/MS). The purification effects and dosages of four carbon nanomaterials, viz. single-walled carbon nanotubes (SWCNTs), MWCNTs, amino-modified MWCNTs, and graphene, were compared. An orthogonal experimental design was used to determine the optimal experimental conditions for sample pretreatment. The experimental factors governing the process were analyzed using variance. The results showed that the optimized sample pretreatment parameters were as follows. Acetonitrile was used as the extraction solvent with ultrasonic extraction for 35 min, while 60 mg MWCNTs, 200 mg PSA, and 200 mg C18, were used as purifiers. The effects of the extraction solvent and the carbon nanomaterials used on the recoveries of the 10 pyrethroid pesticides were significantly different (p<0.001), and the effect of extraction time on the recoveries was statistically different (p<0.05). The dosage of carbon nanomaterials had no significant effect on the recoveries (p>0.05). Good linearities were observed for the 10 pyrethroid pesticides in the concentration range of 0.01-2 mg/L. The limits of detection (LODs) and limits of quantification (LOQs) were in the ranges of 0.001-0.01 mg/kg and 0.005-0.04 mg/kg, respectively. The average recoveries of the pyrethroid pesticides spiked into blank samples of green tea were 91.4%-109.7%, and the relative standard deviations were 0.12%-9.80% (n=6). Furthermore, the matrix effects (MEs) of scented green tea, green tea, and black tea were evaluated. It was found that the addition of MWCNTs to the purifier can effectively reduce the matrix effect in green tea and black tea matrices. The developed method and the national standard method were used to detect the residues of the 10 pyrethroid pesticides in 120 tea samples available in the market. The results showed that cyfluthrin, deltamethrin, fenvalerate, permethrin, fenpropathrin, cypermethrin, bifenthrin and cyhalothrin were detected, and the contents obtained with the two methods were similar. Although pyrethroids were detected in most tea samples, the contents of all pesticide residues were below the maximum residue limits (MRLs). Therefore, the developed method is suitable for the rapid quantitative analysis of pesticide residues in tea.


Assuntos
Nanotubos de Carbono , Resíduos de Praguicidas , Praguicidas , Piretrinas , Cromatografia Gasosa-Espectrometria de Massas/métodos , Nanotubos de Carbono/análise , Nanotubos de Carbono/química , Permetrina/análise , Resíduos de Praguicidas/análise , Praguicidas/análise , Piretrinas/análise , Projetos de Pesquisa , Solventes/análise , Espectrometria de Massas em Tandem , Chá/química
8.
Biol Pharm Bull ; 45(4): 446-451, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35370268

RESUMO

Single-walled carbon nanotubes (SWCNTs) are made from rolled single graphene sheets with a diameter in the nanometer range and are potential carriers for drug delivery systems. However, their effects on uridine 5'-diphosphate-glucuronosyltransferase (UGT) 1A activities remain unclear. The present study aimed to investigate the effect of two kinds of SWCNTs (EC1.5-P- and FH-P-SWCNTs) and other nanocarbons on human UGT1A activity due to the proposed application of SWCNTs in drug and gene delivery. ß-Estradiol 3-glucuronidation, which is catalyzed mainly by UGT1A1, was inhibited by 99 and 76% in the presence of 0.1 mg/mL EC1.5-P- and FH-P-SWCNTs in human liver microsomes, respectively. The observed decrease of free UGT1A1 protein in the enzyme reaction mixture suggests a higher interaction with SWCNTs, and indicates the inhibition of ß-estradiol 3-glucuronidation. Imipramine N-glucuronidation, which is formed mainly by UGT1A4, was also decreased by SWCNTs. Serotonin glucuronidation, which is mainly responsible for UGT1A6, was only influenced by specific nanocarbons in human liver microsomes. The attenuation of free UGT1A6 protein was observed with SWCNTs and carbon black, indicating that UGT1A6 activity was not influenced by the direct interaction of SWCNTs. We also observed a 127% increase by FH-P-SWCNTs for propofol glucuronidation in human liver microsomes, which is catalyzed mainly by UGT1A9. The values of maximum velocity and intrinsic clearance for propofol glucuronidation in the presence of FH-P-SWCNT were 1.8- and 2.0-fold higher than those of the control in human liver microsomes. These results suggest that the effects of SWCNTs on UGT1A are different among isoforms.


Assuntos
Nanotubos de Carbono , Glucuronídeos/metabolismo , Glucuronosiltransferase/metabolismo , Humanos , Fígado/metabolismo , Difosfato de Uridina
9.
J Mol Model ; 28(5): 112, 2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35378623

RESUMO

B3LYP, B97D, and M06-2X density functionals are utilized for probing the effect of decorating X (X = Co, Ti, Sc, or Ca) metals on the sensing performance of an aluminum phosphide nanotube (AlPNT) in detecting the hydrazine (HZ) gas. We predict that the interaction of pristine AlPNT with HZ is physisorption, and our calculated sensing response (SR) of AlPNT is approximately 2.7. The adsorption energy of HZ changes from - 4.6 to - 21.0, - 21.9, - 22.4, and - 23.8 kcal/mol by decorating the Co, Ti, Sc, and Ca metals into the AlPNT surface, respectively. Also, Co, Ti, Sc, and Ca rise the SR to 22.5, 36.8, 50.4, and 89.0, respectively, indicating that by increasing the atomic radius of metals, the sensitivity is more increased. So, we concluded that Ca much more increases the sensitivity of AlPNT toward HZ. Our calculations demonstrate that the electrostatic interaction has the main contribution in the formation of HZ/X decorated AlPNT (X@AlPNT) complexes. The expected recovery time is 22.0 s for the HZ desorption from the Ca@AlPNT at 298 K. Finally, we found that all of the X@AlPNTs have superior sensing performance toward HZ compared to the X@carbon nanotubes.


Assuntos
Nanotubos de Carbono , Compostos de Alumínio , Hidrazinas , Metais , Fosfinas
10.
Microbiol Spectr ; 10(2): e0041022, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35384690

RESUMO

Multiwalled carbon nanotubes (MWCNTs) regularly enter aquatic environments due to their ubiquity in consumer products and engineering applications. However, the effects of MWCNT pollution on the environmental microbiome are poorly understood. Here, we evaluated whether these carbon nanoparticles can elevate the spread of antimicrobial resistance by promoting bacterial plasmid transfer, which has previously been observed for copper nanomaterials with antimicrobial properties as well as for microplastics. Through a combination of experimental liquid mating assays between Pseudomonas putida donor and recipient strains with plasmid pKJK5::gfpmut3b and mathematical modeling, we here demonstrate that the presence of MWCNTs leads to increased plasmid transfer rates in a concentration-dependent manner. The percentage of transconjugants per recipient significantly increased from 0.21 ± 0.04% in absence to 0.41 ± 0.09% at 10 mg L-1 MWCNTs. Similar trends were observed when using an Escherichia coli donor hosting plasmid pB10. The identified mechanism underlying the observed dynamics was the agglomeration of MWCNTs. A significantly increased number of particles with >6 µm diameter was detected in the presence of MWCNTs, which can in turn provide novel surfaces for bacterial interactions between donor and recipient cells after colonization. Fluorescence microscopy confirmed that MWCNT agglomerates were indeed covered in biofilms that contained donor bacteria as well as elevated numbers of green fluorescent transconjugant cells containing the plasmid. Consequently, MWCNTs provide bacteria with novel surfaces for intense cell-to-cell interactions in biofilms and can promote bacterial plasmid transfer, hence potentially elevating the spread of antimicrobial resistance. IMPORTANCE In recent decades, the use of carbon nanoparticles, especially multiwalled carbon nanotubes (MWCNTs), in a variety of products and engineering applications has been growing exponentially. As a result, MWCNT pollution into environmental compartments has been increasing. We here demonstrate that the exposure to MWCNTs can affect bacterial plasmid transfer rates in aquatic environments, an important process connected to the spread of antimicrobial resistance genes in microbial communities. This is mechanistically explained by the ability of MWCNTs to form bigger agglomerates, hence providing novel surfaces for bacterial interactions. Consequently, increasing pollution with MWCNTs has the potential to elevate the ongoing spread of antimicrobial resistance, a major threat to human health in the 21st century.


Assuntos
Nanotubos de Carbono , Antibacterianos/farmacologia , Bactérias/genética , Escherichia coli/genética , Humanos , Plasmídeos/genética , Plásticos/farmacologia
11.
Sensors (Basel) ; 22(7)2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35408075

RESUMO

Silicon-on-insulator (SOI) nanowire or nanoribbon field-effect transistor (FET) biosensors are versatile platforms of electronic detectors for the real-time, label-free, and highly sensitive detection of a wide range of bioparticles. At a low analyte concentration in samples, the target particle diffusion transport to sensor elements is one of the main limitations in their detection. The dielectrophoretic (DEP) manipulation of bioparticles is one of the most successful techniques to overcome this limitation. In this study, TCAD modeling was used to analyze the distribution of the gradient of the electric fields E for the SOI-FET sensors with embedded DEP electrodes to optimize the conditions of the dielectrophoretic delivery of the analyte. Cases with asymmetrical and symmetrical rectangular electrodes with different heights, widths, and distances to the sensor, and with different sensor operation modes were considered. The results showed that the grad E2 factor, which determines the DEP force and affects the bioparticle movement, strongly depended on the position of the DEP electrodes and the sensor operation point. The sensor operation point allows one to change the bioparticle movement direction and, as a result, change the efficiency of the delivery of the target particles to the sensor.


Assuntos
Técnicas Biossensoriais , Nanotubos de Carbono , Nanofios , Eletroforese/métodos , Silício , Transistores Eletrônicos
12.
Sensors (Basel) ; 22(7)2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35408313

RESUMO

An impedance technique-based aptasensor for the detection of thrombin was developed using a single-walled carbon nanotube (SWCNT)-modified screen-printed carbon electrode (SPCE). In this work, a thrombin-binding aptamer (TBA) as probe was used for the determination of thrombin, and that was immobilized on SWCNT through π-π interaction. In the presence of thrombin, the TBA on SWCNT binds with target thrombin, and the amount of TBA on the SWCNT surface decreases. The detachment of TBA from SWCNT will be affected by the concentration of thrombin and the remaining TBA on the SWCNT surface can be monitored by electrochemical methods. The TBA-modified SWCNT/SPCE sensing layer was characterized by cyclic voltammetry (CV). For the measurement of thrombin, the change in charge-transfer resistance (Rct) of the sensing interface was investigated using electrochemical impedance spectroscopy (EIS) with a target thrombin and [Fe(CN)6]3- as redox maker. Upon incubation with thrombin, a decrease of Rct change was observed due to the decrease in the repulsive interaction between the redox marker and the electrode surface without any label. A plot of Rct changes vs. the logarithm of thrombin concentration provides the linear detection ranges from 0.1 nM to 1 µM, with a ~0.02 nM detection limit.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanotubos de Carbono , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Impedância Elétrica , Técnicas Eletroquímicas/métodos , Eletrodos , Limite de Detecção , Nanotubos de Carbono/química , Trombina/química
13.
Sensors (Basel) ; 22(7)2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35408320

RESUMO

In this work, we propose a novel functionalized carbon nanotube (f-CNT) supporting nanoporous cauliflower-like Pd nanostructures (PdNS) as an enzyme-free interface for glucose electrooxidation reaction (GOR) in a neutral medium (pH 7.4). The novelty resides in preparing the PdNS/f-CNT biomimetic nanocatalyst using a cost-effective and straightforward method, which consists of drop-casting well-dispersed f-CNTs over the Screen-printed carbon electrode (SPCE) surface, followed by the electrodeposition of PdNS. Several parameters affecting the morphology, structure, and catalytic properties toward the GOR of the PdNS catalyst, such as the PdCl2 precursor concentration and electrodeposition conditions, were investigated during this work. The electrochemical behavior of the PdNS/f-CNT/SPCE toward GOR was investigated through Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), and amperometry. There was also a good correlation between the morphology, structure, and electrocatalytic activity of the PdNS electrocatalyst. Furthermore, the LSV response and potential-pH diagram for the palladium-water system have enabled the proposal for a mechanism of this GOR. The proposed mechanism would be beneficial, as the basis, to achieve the highest catalytic activity by selecting the suitable potential range. Under the optimal conditions, the PdNS/f-CNT/SPCE-based biomimetic sensor presented a wide linear range (1-41 mM) with a sensitivity of 9.3 µA cm-2 mM-1 and a detection limit of 95 µM (S/N = 3) toward glucose at a detection potential of +300 mV vs. a saturated calomel electrode. Furthermore, because of the fascinating features such as fast response, low cost, reusability, and poison-free characteristics, the as-proposed electrocatalyst could be of great interest in both detection systems (glucose sensors) and direct glucose fuel cells.


Assuntos
Técnicas Biossensoriais , Nanoporos , Nanotubos de Carbono , Técnicas Biossensoriais/métodos , Eletrodos , Glucose/química , Concentração de Íons de Hidrogênio , Nanotubos de Carbono/química
14.
Molecules ; 27(7)2022 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-35408516

RESUMO

The expanding uses of carbon nanotubes (CNTs) in industry and medicine have raised concerns about their toxicity on human and animal health. CNTs, including multi-walled nanotubes (MWCNTs), have been reported to induce immunotoxic, inflammatory, and oxidative effects. Quercetin is a natural flavonoid present in many vegetables and fruits and has immunomodulatory, anti-inflammatory, and antioxidant properties. Herein, we investigated the protective effects of quercetin on pristine MWCNTs-induced immunotoxicity in mice. In comparison with two doses of MWCNTs, high doses [0.5 mg/kg body weight (BW), once intraperitoneally (IP)] caused higher immunotoxic, inflammatory, and oxidative effects than low doses (0.25 mg/kg BW, once IP). Administration of quercetin (30 mg/kg BW, IP for 2 weeks) relieved these deleterious effects as evidenced by (1) reduced spleen weight, (2) increased number of total leukocytes, lymphocytes, and neutrophils, (3) elevated serum levels of IgM, IgG, and IgA, (4) decreased lipid peroxide malondialdehyde levels and increased levels of antioxidant markers reduced glutathione, superoxide dismutase, and catalase in the spleen, (5) decreased concentrations and mRNA levels of inflammatory markers tumor necrosis factor-alpha (TNFα), interleukin 1 beta (IL1ß), and IL6 in the spleen, (6) downregulated expression of immunomodulatory genes transforming growth factor-beta (TGFß), cyclooxygenase2 (COX2), and IL10, and (7) regenerative histological changes as indicated by decreased mononuclear cell infiltration, minimized degenerative changes and restored lymphocytes depletion in the spleen. These results infer that quercetin can ameliorate MWCNTs-induced immunotoxic, inflammatory, and oxidative effects.


Assuntos
Nanotubos de Carbono , Quercetina , Animais , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Glutationa/metabolismo , Camundongos , Nanotubos de Carbono/toxicidade , Estresse Oxidativo , Quercetina/farmacologia
15.
Part Fibre Toxicol ; 19(1): 30, 2022 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-35449069

RESUMO

BACKGROUND: Considering the expanding industrial applications of carbon nanotubes (CNTs), safety assessment of these materials is far less than needed. Very few long-term in vivo studies have been carried out. This is the first 2-year in vivo study to assess the effects of double walled carbon nanotubes (DWCNTs) in the lung and pleura of rats after pulmonary exposure. METHODS: Rats were divided into six groups: untreated, Vehicle, 3 DWCNT groups (0.12 mg/rat, 0.25 mg/rat and 0.5 mg/rat), and MWCNT-7 (0.5 mg/rat). The test materials were administrated by intratracheal-intrapulmonary spraying (TIPS) every other day for 15 days. Rats were observed without further treatment until sacrifice. RESULTS: DWCNT were biopersistent in the rat lung and induced marked pulmonary inflammation with a significant increase in macrophage count and levels of the chemotactic cytokines CCL2 and CCL3. In addition, the 0.5 mg DWCNT treated rats had significantly higher pulmonary collagen deposition compared to the vehicle controls. The development of carcinomas in the lungs of rats treated with 0.5 mg DWCNT (4/24) was not quite statistically higher (p = 0.0502) than the vehicle control group (0/25), however, the overall incidence of lung tumor development, bronchiolo-alveolar adenoma and bronchiolo-alveolar carcinoma combined, in the lungs of rats treated with 0.5 mg DWCNT (7/24) was statistically higher (p < 0.05) than the vehicle control group (1/25). Notably, two of the rats treated with DWCNT, one in the 0.25 mg group and one in the 0.5 mg group, developed pleural mesotheliomas. However, both of these lesions developed in the visceral pleura, and unlike the rats administered MWCNT-7, rats administered DWCNT did not have elevated levels of HMGB1 in their pleural lavage fluids. This indicates that the mechanism by which the mesotheliomas that developed in the DWCNT treated rats is not relevant to humans. CONCLUSIONS: Our results demonstrate that the DWCNT fibers we tested are biopersistent in the rat lung and induce chronic inflammation. Rats treated with 0.5 mg DWCNT developed pleural fibrosis and lung tumors. These findings demonstrate that the possibility that at least some types of DWCNTs are fibrogenic and tumorigenic cannot be ignored.


Assuntos
Neoplasias Pulmonares , Mesotelioma , Nanotubos de Carbono , Animais , Exposição por Inalação/efeitos adversos , Pulmão , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Mesotelioma/patologia , Nanotubos de Carbono/toxicidade , Pleura , Ratos
16.
Dalton Trans ; 51(16): 6339-6344, 2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35383810

RESUMO

Encapsulation of a metallofullerene single-molecule magnet, Dy2ScN@C80, into single-wall carbon nanotubes (SWCNTs) accelerates magnetic relaxation processes. In contrast, encapsulation of DySc2N@C80 suppresses them. The effects of the encapsulation are discussed in terms of intermolecular magnetic interactions and charge transfer among metallofullerenes and SWCNTs.


Assuntos
Nanotubos de Carbono , Fenômenos Magnéticos , Magnetismo , Fenômenos Físicos
17.
Food Chem Toxicol ; 163: 112994, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35398444

RESUMO

Organophosphorus pesticides are widely utilized in agricultural fertility. However, their long-term accumulations result in serious damage to human health and ecological balance. Paraoxon (PAR) can block acetylcholinesterase in the human body, resulting in death. Thus, in this study, a molecularly imprinted electrochemical PAR sensor based on multiwalled carbon nanotubes (MWCNTs)/molybdenum disulfide nanoparticles (MoS2NPs) nanocomposite (MoS2NPs@MWCNTs) was proposed for selective tap water determination. A hydrothermal fabrication approach was firstly implemented to prepare MoS2NPs@MWCNTs nanocomposite. Afterwards, the formation of PAR imprinted electrochemical electrode was performed on nanocomposite modified glassy carbon electrode (GCE) in presence of PAR as template and pyrrole (Py) as a monomer by cyclic voltammetry (CV) technique. Just after determining the physicochemical features of as-fabricated nanostructures by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), Raman spectroscopy, and atomic force microscopy (AFM), the electrochemical behavior of the fabricated sensors was determined through CV, differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The suggested imprinted electrode provided the acceptable limit of quantification (LOQ) and limit of detection (LOD) values of 1.0 × 10-11 M, and 2.0 × 10-12 M, respectively. As a consequence, the proposed PAR imprinted electrochemical sensor can be offered for the determining safe tap water and its utility.


Assuntos
Impressão Molecular , Nanotubos de Carbono , Praguicidas , Acetilcolinesterase , Técnicas Eletroquímicas/métodos , Humanos , Nanotubos de Carbono/química , Compostos Organofosforados , Paraoxon , Água
18.
PLoS One ; 17(4): e0265685, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35385490

RESUMO

Controlled assembly of retinal cells on artificial surfaces is important for fundamental cell research and medical applications. We investigate fractal electrodes with branches of vertically-aligned carbon nanotubes and silicon dioxide gaps between the branches that form repeating patterns spanning from micro- to milli-meters, along with single-scaled Euclidean electrodes. Fluorescence and electron microscopy show neurons adhere in large numbers to branches while glial cells cover the gaps. This ensures neurons will be close to the electrodes' stimulating electric fields in applications. Furthermore, glia won't hinder neuron-branch interactions but will be sufficiently close for neurons to benefit from the glia's life-supporting functions. This cell 'herding' is adjusted using the fractal electrode's dimension and number of repeating levels. We explain how this tuning facilitates substantial glial coverage in the gaps which fuels neural networks with small-world structural characteristics. The large branch-gap interface then allows these networks to connect to the neuron-rich branches.


Assuntos
Fractais , Nanotubos de Carbono , Eletrodos , Nanotubos de Carbono/química , Neuroglia , Neurônios
19.
J Chromatogr A ; 1670: 462997, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35367894

RESUMO

In this present work, the synthesis of nitrogen doped multi walled carbon nanotubes (N-MWCNTs) grafted Sodium-carboxy methyl cellulose (Na-CMC) hybrid composite was carried out via thermal reduction process. The hybrid composites were thermodynamically characterized by inverse gas chromatography (IGC) and compared to Na-CMC particles. The results were obtained by using 14 different IGC methods and models. We proved that the free energy of adsorption of the different solvents on N-MWCNTs-Na-CMC surface was equal to the summation of both free enthalpies of the solvents separately adsorbed on N-MWCNT and on Na-CMC surfaces. The London dispersive surface free energy of different materials was calculated by using the various molecular models. The more precise results were obtained by Hamieh model based on the effect of the temperature on the surface area of organic molecules. It was proved that the dispersive component of the surface energy of N-MWCNTs-Na-CMC was equal to the geometric mean than that of N-MWCNTs and Na-CMC surfaces. Lewis Acid base properties of the various materials were determined by using the different models and methods. A stronger basic character was highlighted for the different solid surfaces with more accentuated acid base character for N-MWCNT solid. Furthermore, the potential usage of the hybrid nanocomposite was studied for the practical application of the self-powered UV photodetection. On the other hand, the N-MWCNTs-Na-CMC hybrid heterostructure N-MWCNTs-Na-CMC exhibited excellent photoresponse characteristics with a good stability and reproducibility under the UV illumination (λ=382 nm) at zero bias. The high photoresponse performances were mainly attributed to the improved conductivity and enhanced charge transfer resulting from the synergetic effect of N-MWCNTs-Na-CMC hybrid heterostructure. The detailed photoresponse properties of the N-MWCNTs-Na-CMC hybrid heterostructure was discussed in detail using energy band theory.


Assuntos
Nanotubos de Carbono , Ácidos , Carboximetilcelulose Sódica , Cromatografia Gasosa/métodos , Materiais Dentários , Nanotubos de Carbono/química , Nitrogênio , Reprodutibilidade dos Testes , Solventes
20.
J Hazard Mater ; 433: 128826, 2022 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-35381513

RESUMO

A 100-day soil incubation experiment was conducted to explore the effects of conventional (high-density polyethylene, HDPE) and biodegradable (polylactic acid, PLA) microplastics (MPs) and multiwall carbon nanotubes (MWCNTs) on soil geochemical properties and bacterial communities. Generally, soil pH was increased by 10% HDPE and 10% PLA, but decreased by increasing MWCNTs. Soil dissolved organic carbon content was only increased by 10% PLA. NO3--N content was significantly decreased by MPs, with a decrement of 99% by 10% PLA. Similarly, available P content was reduced by 10% MPs. The activities of urease and alkaline phosphatase were stimulated by 10% PLA, but generally inhibited by HDPE. Conversely, FDAse activity was stimulated by HDPE, but inhibited by 10% PLA, whereas invertase activity decreased with increasing MWCNTs. Overall, both MPs and MWCNTs changed soil bacterial diversity. Co-exposure to 10% MPs and MWCNTs of 1 and 10 mg/kg caused the lowest species richness and Shannon indexes. MPs especially at the 10% dose changed bacterial community composition and the associated metabolic pathways, causing the enrichment of specific taxa and functional genes. Our findings show that conventional and biodegradable MPs differently change soil geochemical properties and microbial community structure and functions, which can be further modified by co-existing MWCNTs.


Assuntos
Nanotubos de Carbono , Solo , Bactérias/genética , Microplásticos , Nanotubos de Carbono/toxicidade , Plásticos , Poliésteres , Polietileno , Solo/química , Microbiologia do Solo
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