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1.
Ecotoxicol Environ Saf ; 205: 111316, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33007600

RESUMO

The interaction between multi-walled carbon nanotubes (MWCNTs) and soil heavy metals was rarely studied. With the convenience of detecting multiple metal elements by ICP-AES, this paper examined the potential effectiveness of MWCNTs on extractability of antimony (Sb) and cadmium (Cd) in contaminated soil. Three-step sequential extraction procedure, toxicity characteristic leaching procedure, bioaccessibility and CaCl2 single extraction were employed to evaluate Sb and Cd speciations and their extractabilities. According to our results, only at low Sb content level of 100 mg/kg, antimony bioavailability reduced with MWCNTs addition of 0.3% and 0.9% by 22.97% and 20.74%, respectively, which might due to the increase of adsorption point, nevertheless, the excess Sb(OH)6- was not adsorbed more efficiently. Secondly, due to the difference in effective specific surface area, only under the condition of high content level and MWCNTs addition of 0.1%, the mild acid-soluble fraction increased at most by 15.40% for Sb and 9.40% for Cd, respectively. However, in terms of TCLP-extractable Sb and Cd and CaCl2-extractable Sb and Cd, no significant, continuous, regular extractability pattern were found. Overall, MWCNTs were selective on extractability of soil heavy metals due to mechanisms of physical adsorption. This paper provides data reference for the interaction between MWCNTs and soil heavy metals extractability.


Assuntos
Cádmio/química , Nanotubos de Carbono/química , Poluentes do Solo/química , Adsorção , Antimônio , Disponibilidade Biológica , Poluição Ambiental , Metais Pesados , Solo
2.
Nat Commun ; 11(1): 4602, 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32929071

RESUMO

Human behaviors are extremely sophisticated, relying on the adaptive, plastic and event-driven network of sensory neurons. Such neuronal system analyzes multiple sensory cues efficiently to establish accurate depiction of the environment. Here, we develop a bimodal artificial sensory neuron to implement the sensory fusion processes. Such a bimodal artificial sensory neuron collects optic and pressure information from the photodetector and pressure sensors respectively, transmits the bimodal information through an ionic cable, and integrates them into post-synaptic currents by a synaptic transistor. The sensory neuron can be excited in multiple levels by synchronizing the two sensory cues, which enables the manipulating of skeletal myotubes and a robotic hand. Furthermore, enhanced recognition capability achieved on fused visual/haptic cues is confirmed by simulation of a multi-transparency pattern recognition task. Our biomimetic design has the potential to advance technologies in cyborg and neuromorphic systems by endowing them with supramodal perceptual capabilities.


Assuntos
Células Receptoras Sensoriais/fisiologia , Tato/fisiologia , Visão Ocular/fisiologia , Animais , Linhagem Celular , Eletrodos , Humanos , Camundongos , Movimento (Física) , Nanotubos de Carbono/química , Reconhecimento Automatizado de Padrão
3.
Pharm Res ; 37(10): 193, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32914377

RESUMO

PURPOSE: The incidence of breast cancer worldwide has been on the rise since the late 1970s, and it has become a common tumor that threatens women's health. Aminoglutethimide (AG) is a common treatment of breast cancer. However, current treatments require frequent dosing that results in unstable plasma concentration and low bioavailability, risking serious adverse reactions. Our goal was to develop a molecularly imprinted polymer (MIP) based delivery system to control the release of AG and demonstrate the availability of this drug delivery system (DDS), which was doped with carbon nanotube with aid of metal-organic gel. METHODS: Preparation of MIP was optimized by key factors including composition of formula, ratio of monomers and drug loading concentration. RESULTS: By using multi-walled carbon nanotubes (MWCNT) and metal-organic gels (MOGs), MIP doubled the specific surface area, pore volume tripled and the IF was 1.6 times than the reference. Compared with commercial tablets, the relative bioavailability was 143.3% and a more stable release appeared. CONCLUSIONS: The results highlight the influence of MWCNT and MOGs on MIP, which has great potential as a DDS.


Assuntos
Aminoglutetimida/química , Antineoplásicos Hormonais/química , Complexos de Coordenação/química , Sistemas de Liberação de Medicamentos/métodos , Nanotubos de Carbono/química , Aminoglutetimida/administração & dosagem , Aminoglutetimida/farmacocinética , Animais , Antineoplásicos Hormonais/administração & dosagem , Antineoplásicos Hormonais/farmacocinética , Complexos de Coordenação/administração & dosagem , Compostos Férricos/química , Géis/administração & dosagem , Géis/química , Humanos , Células MCF-7 , Masculino , Impressão Molecular/métodos , Ratos , Ácidos Tricarboxílicos/química
4.
Life Sci ; 258: 118152, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32735881

RESUMO

AIMS: Cancer stem cells (CSCs) are the source of tumors and play a key role in the resistance of cancer to therapies. To improve the current therapies against CSCs, in this work we developed a novel system of electrospun polycaprolactone (PCL) nanofibers containing hydroxylated multi-walled carbon nanotubes (MWCNTs-OH) and all-trans retinoic acid (ATRA). MATERIALS AND METHODS: The nanofiber membranes were forged by electrospinning, and the physical and chemical properties of the nanofiber membranes were evaluated by scanning electron microscopy, XRD and Raman etc. The photothermal properties of nanofiber membranes and their effects on CSCs differentiation and cytotoxicity were investigated. Finally, the anti-tumor effect of nanofiber membranes in vivo was evaluated. KEY FINDINGS: The nanofibers formed under optimal conditions were smooth without beads. The nanofibrous membranes with MWCNTs-OH could increase temperature of the medium under near-infrared (NIR) illumination to suppress the viability of glioma stem cells (GSCs). Meanwhile, the added ATRA could further induce the differentiation of GSCs to destroy their stemness and reduce their resistance to heat treatment. Compared with no NIR irradiation, after 2min NIR irradiation, the membranes reduced the in-vitro viability of GSCs by 13.41%, 14.83%, and 26.71% after 1, 2, and 3 days, respectively. After 3 min daily illumination for 3 days, the viability of GSCs was only 22.75%, and similar results were observed in vivo. SIGNIFICANCE: These results showed efficiently cytotoxicity to CSCs by combining heat therapy and differentiation therapy. The nanofiber membranes if inserted at the site after surgical tumor removal, may hinder tumor recurrence.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias Encefálicas/terapia , Glioma/terapia , Nanofibras/uso terapêutico , Células-Tronco Neoplásicas/efeitos dos fármacos , Tretinoína/uso terapêutico , Animais , Antineoplásicos/administração & dosagem , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Glioma/patologia , Humanos , Hipertermia Induzida/métodos , Masculino , Camundongos Endogâmicos BALB C , Nanofibras/química , Nanotubos de Carbono/química , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/prevenção & controle , Células-Tronco Neoplásicas/patologia , Poliésteres/química , Poliésteres/uso terapêutico , Tretinoína/administração & dosagem
5.
J Chromatogr A ; 1627: 461382, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823094

RESUMO

A method is described for the functionalization of magnetic carbon nanotubes to recognize aristolochic acid Ⅰ and Ⅱ. 3-Glycidyloxypropyltrimethoxysilane was used as a coupling agent to immobilize adenine on a solid support. The morphology and structure of adenine-coated magnetic carbon nanotubes was investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). The adsorption performance of the adenine-coated magnetic carbon nanotubes was evaluated via adsorption isotherms, the kinetics and selectivity tests. The adsorption capacity of the adenine-functionalized sorbent for aristolochic acid Ⅰ was determined to be 24.5 µg mg-1. By combining magnetic solid phase extraction with HPLC detection, a method was developed to enrich and detect aristolochic acids used in traditional Chinese medicine. A satisfactory recovery (92.7 - 97.5% for aristolochic acid Ⅰ and 92.6 - 99.4% for aristolochic acid Ⅱ) and an acceptable relative standard deviation (<4.0%) were obtained.


Assuntos
Adenina/química , Ácidos Aristolóquicos/isolamento & purificação , Fenômenos Magnéticos , Nanotubos de Carbono/química , Adsorção , Medicamentos de Ervas Chinesas/química , Compostos Férricos/síntese química , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Cinética , Nanocompostos/química , Nanotubos de Carbono/ultraestrutura , Concentração Osmolar , Reprodutibilidade dos Testes , Dióxido de Silício/síntese química , Dióxido de Silício/química , Extração em Fase Sólida , Temperatura , Difração de Raios X
6.
Int J Nanomedicine ; 15: 4991-5004, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764931

RESUMO

Introduction: Various materials and approaches have been used to reduce the mesh-induced inflammatory response and modify the mesh with tissue-matched mechanical properties, aiming to improve the repair of abdominal wall defects. Materials and Methods: In this study, we fabricated a polycaprolactone (PCL)/silk fibroin (SF) mesh integrated with amoxicillin (AMX)-incorporating multiwalled carbon nanotubes (MWCNTs) via electrospinning, grafting and crosslinking, developing a sustainable antibiotic and flexible mesh. AMX was loaded into the hollow tubular MWCNTs by physical adsorption, and a nanofibrous structure was constructed by electrospinning PCL and SF (40:60 w/w). The AMX@MWCNTs were then chemically grafted onto the surfaces of the PCL/SF nanofibers by treating with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) solution for simultaneous crosslinking and coating. The incorporation of AMX into the MWCNTs (AMX@MWCNTs) and the integration of the AMX@MWCNTs with the PCL/SF nanofibers were characterized. Then, the functional mesh was fabricated and fully evaluated in terms of antibacterial activity, mechanical properties and host response. Results: Our results demonstrated that the PCL/SF nanofibrous structure was fabricated successfully by electrospinning. After integrating with AMX@MWCNT by grafting and crosslinking, the functional mesh showed undeformed structure, modified surface hydrophilicity and biocompatible interfaces, abdominal wall-matched mechanical properties, and a sustained-release antibiotic profile in E. coli growth inhibition compared to those of PCL/SF mesh in vitro. In a rat model with subcutaneous implantation, the functional mesh incited less mesh-induced inflammatory and foreign body responses than PCL/SF mesh within 14 days. The histological analysis revealed less infiltration of granulocytes and macrophages during this period, resulting in the loosely packed collagen deposition on the functional mesh and prominent collagen incorporation. Discussion: Therefore, this designed PCL/SF-AMX@MWCNT nanofibrous mesh, functionalized with antibacterial and tissue-matched mechanical properties, provides a promising alternative for the repair of abdominal wall defects.


Assuntos
Amoxicilina/química , Antibacterianos/química , Nanofibras/química , Nanotecnologia/métodos , Telas Cirúrgicas , Amoxicilina/farmacocinética , Amoxicilina/farmacologia , Animais , Antibacterianos/farmacocinética , Antibacterianos/farmacologia , Colágeno/química , Colágeno/metabolismo , Reagentes para Ligações Cruzadas/química , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Fibroínas/química , Inflamação/etiologia , Masculino , Teste de Materiais , Camundongos , Nanotubos de Carbono/química , Poliésteres/química , Ratos Sprague-Dawley , Telas Cirúrgicas/efeitos adversos
7.
J Chromatogr A ; 1625: 461267, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709320

RESUMO

We describe the design and performance evaluation of a portable gas chromatograph suitable for the analysis of volatile organic and odorous compounds at trace levels. The system comprises a carbon nanotube sponge preconcentrator, an electronic pressure control (EPC) unit, a temperature-programmable column module, and a fast-response photoionization detector. A built-in tablet computer controls instrumental parameters and chromatogram display functions. The compact GC with dimensions of 35 cm (l) × 26 cm (w) × 15 cm (h) is self-contained, weighing less than 5 kg without a battery pack, and uses no auxiliary compressed gases. Our design has three main advantages over conventional portable GCs: recharging configuration of ambient air as the carrier gas using a miniature diaphragm pump, precise control of column flow by the built-in canister and EPC system, and rapid thermal desorption of the preconcentrator facilitated by intrinsic resistivity of the carbon nanotube sponge. A 30 m, 0.28 mm I.D. capillary column operated at a head pressure of 14 psi provided a peak capacity of 55 for a 10 min isothermal analysis. The temperature-programmability feature could decrease the analysis time of less than 5 min for vapor mixture of benzene, toluene, ethylbenzene, and o-xylene. More than a 100-fold increase in sensitivity by preconcentrating a sample adsorption volume of 90 mL resulted in improved detection limits of 0.13 (benzene), 0.20 (toluene), 0.23 (ethylbenzene), and 0.28 (o-xylene) ppb (v/v). Our instrument displayed good stability and reproducibility of retention times (< 0.14% RSD) and intensities (< 4.5% RSD) for continuous measurements using the preconcentrator over 10 h. Thus, continuous and on-site determinations of trace volatile organic compounds in air samples with this instrument appear feasible.


Assuntos
Poluentes Atmosféricos/análise , Cromatografia Gasosa/métodos , Sistemas Computacionais , Hidrocarbonetos Aromáticos/análise , Compostos Orgânicos Voláteis/análise , Calibragem , Gases/análise , Limite de Detecção , Nanotubos de Carbono/química , Odorantes/análise , Pressão , Reprodutibilidade dos Testes , Temperatura , Fatores de Tempo
8.
Int J Mol Sci ; 21(15)2020 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-32717853

RESUMO

As SARS-CoV-2 is spreading rapidly around the globe, adopting proper actions for confronting and protecting against this virus is an essential and unmet task. Reactive oxygen species (ROS) promoting molecules such as peroxides are detrimental to many viruses, including coronaviruses. In this paper, metal decorated single-wall carbon nanotubes (SWCNTs) were evaluated for hydrogen peroxide (H2O2) adsorption for potential use for designing viral inactivation surfaces. We employed first-principles methods based on the density functional theory (DFT) to investigate the capture of an individual H2O2 molecule on pristine and metal (Pt, Pd, Ni, Cu, Rh, or Ru) decorated SWCNTs. Although the single H2O2 molecule is weakly physisorbed on pristine SWCNT, a significant improvement on its adsorption energy was found by utilizing metal functionalized SWCNT as the adsorbent. It was revealed that Rh-SWCNT and Ru-SWCNT systems demonstrate outstanding performance for H2O2 adsorption. Furthermore, we discovered through calculations that Pt- and Cu-decorated SWNCT-H2O2 systems show high potential for filters for virus removal and inactivation with a very long shelf-life (2.2 × 1012 and 1.9 × 108 years, respectively). The strong adsorption of metal decorated SWCNTs and the long shelf-life of these nanomaterials suggest they are exceptional candidates for designing personal protection equipment against viruses.


Assuntos
Betacoronavirus/efeitos dos fármacos , Desinfetantes/farmacologia , Peróxido de Hidrogênio/análise , Nanotubos de Carbono/química , Adsorção , Infecções por Coronavirus/prevenção & controle , Teoria da Densidade Funcional , Desinfetantes/química , Estabilidade de Medicamentos , Humanos , Ferro/química , Ferro/farmacologia , Pandemias/prevenção & controle , Equipamento de Proteção Individual , Platina/química , Platina/farmacologia , Pneumonia Viral/prevenção & controle , Ródio/química , Ródio/farmacologia , Rutênio/química , Rutênio/farmacologia , Inativação de Vírus
9.
Food Chem ; 333: 127540, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32682226

RESUMO

A novel of magnetic dummy-template molecularly imprinted polymers (mag-MWCNTs-DMIPs) were prepared by surface molecular imprinting technique. The structure of polymers were characterized and the binding properties were assessed by adsorption experiments. The synthetic mag-MWCNTs-DMIPs exhibit satisfying adsorption capacity, excellent selectivity and fast adsorption rate toward phenoxy carboxylic acid (PCA) herbicides. Afterwards, a reliable analytical method for selective separation and determination of trace PCA herbicides in cereals was established by using magnetic solid-phase extraction (mag-MWCNTs-DMIPs as magnetic adsorbent) and UPLC-MS/MS detection. A series of requisite factors were optimized in detail to achieve expected extraction performance. Under the optimum MSPE parameters, the mean spiked recoveries for analytes in different cereals ranged from 86.7% to 95.2% with intra- and inter-day precision not greater than 8.5% and 10.6%, respectively. At last, the developed method was successfully utilized for determination the four PCA herbicides in actual cereals.


Assuntos
Ácidos Carboxílicos/análise , Ácidos Carboxílicos/isolamento & purificação , Grão Comestível/química , Herbicidas/química , Impressão Molecular , Nanotubos de Carbono/química , Extração em Fase Sólida/métodos , Adsorção , Ácidos Carboxílicos/química , Contaminação de Alimentos/análise , Imãs/química , Polímeros/síntese química , Polímeros/química , Fatores de Tempo
10.
PLoS One ; 15(7): e0236529, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32697797

RESUMO

In this study, functionalized multi-walled carbon nanotubes (MWCNT-NH2) were synthesized as an additive for the preparation of mixed matrix membranes (MMMs) and then were investigated by FTIR and FE-SEM techniques. Polyether sulfone (PES) polymeric membrane modified with functionalized MWCNT-NH2 carbon nanotubes was prepared by phase inversion method. The effect of MWCNT-NH2 on the morphology and property of the PES membrane was evaluated using scanning electron microscopy. The flux, enrichment factor and swelling properties of modified membranes were also used to investigate the membranes performance. The results showed that the flux and enrichment factor in modified PES membrane containing 5 wt.% of functionalized MWCNT-NH2 carbon nanotubes were obtained 1.2 L.m-2h-1 and 3.3, respectively. The influence of methanol concentration on the flux and enrichment factor was investigated. The results corroborated that the flux didn't change significantly, while the enrichment factor was decreased.


Assuntos
Membranas Artificiais , Nanotubos de Carbono/química , Polímeros/química , Sulfonas/química , Metanol/química , Porosidade , Água/química , Purificação da Água/métodos
11.
Food Chem ; 333: 127524, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32679418

RESUMO

Semicarbazide (SEM) is a protein-bound nitrofurazone metabolite that is detrimental to human health. Therefore, to ensure food safety, it is necessary to detect SEM in food samples. To this end, we developed a novel electrochemical sensor to detect SEM by using a molecularly imprinted polymer (MIP) as the recognition element. Computer-aided molecular modelling was performed to guide the synthesis of the MIP, and subsequently, MIP/carboxylated single-walled carbon-nanotubes/chitosan (MIP/SWNTs-COOH/CS) was prepared as the sensing platform to develop the electrochemical sensor. The linear range of the sensor was 0.04-7.6 ng mL-1, with a detection limit of 0.025 ng mL-1. The sensor was successfully applied to detect SEM in four different real samples, with recoveries ranging from 83.16% to 93.40%. The results indicated that the fabricated electrochemical sensor can be widely applied to detect SEM in the environment and in agri-food products.


Assuntos
Quitosana/química , Técnicas Eletroquímicas/métodos , Impressão Molecular , Nanotubos de Carbono/química , Semicarbazidas/análise , Eletrodos , Mel/análise , Humanos , Limite de Detecção , Carne/análise , Polímeros/química , Reprodutibilidade dos Testes , Alimentos Marinhos/análise
12.
PLoS One ; 15(7): e0236599, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32722685

RESUMO

The increasing prevalence of carbon nanotubes (CNTs) as components of new functional materials has the unintended consequence of causing increases in CNT concentrations in aqueous environments. Aqueous systems are reservoirs for bacteria, including human and animal pathogens, that can form biofilms. At high concentrations, CNTs have been shown to display biocidal effects; however, at low concentrations, the interaction between CNTs and bacteria is more complicated, and antimicrobial action is highly dependent upon the properties of the CNTs in suspension. Here, impact of low concentrations of multiwalled CNTs (MWCNTs) on the biofilm-forming opportunistic human pathogen Pseudomonas aeruginosa is studied. Using phase contrast and confocal microscopy, flow cytometry, and antibiotic tolerance assays, it is found that sub-lethal concentrations (2 mg/L) of MWCNTs promote aggregation of P. aeruginosa into multicellular clusters. However, the antibiotic tolerance of these "young" bacterial-CNT aggregates is similar to that of CNT-free cultures. Overall, our results indicate that the co-occurrence of MWCNTs and P. aeruginosa in aqueous systems, which promotes the increased number and size of bacterial aggregates, could increase the dose to which humans or animals are exposed.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Nanotubos de Carbono/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/fisiologia , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Suspensões
13.
Ecotoxicol Environ Saf ; 201: 110862, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32559691

RESUMO

In this study, a novel electrochemical sensor based on self-assembled rod-like lanthanum hydroxide-oxidized multi-walled carbon nanotubes (La(OH)3-OxMWCNTs) nanocomposite was developed for sensitive determination of p-nitrophenol (p-NP). The La(OH)3-OxMWCNTs nanocomposite with an interpenetrating networks structure was characterized by field emission electron microscope (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, Raman spectra and X-ray photoelectron spectroscopy (XPS). The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements were performed to study the electrochemical behaviors of La(OH)3-OxMWCNTs modified glassy carbon electrode (La(OH)3-OxMWCNTs/GCE). The La(OH)3-OxMWCNTs/GCE was used for sensitive determination of p-NP by CV and linear sweep voltammetry (LSV). Under the optimum conditions, the peak currents of LSV versus the concentrations of p-NP in the range 1.0-30.0 µmol L-1 showed a good linear relationship (R2=0.9971), and the limit of detection (LOD) was calculated to be 0.27 µmol L-1 (signal-to-noise ratio of 3, S/N=3). The recoveries of p-NP in real samples of industrial wastewater and Xiangjiang water at La(OH)3-OxMWCNTs/GCE were in the range of 95.62-110.75% with relative standard deviation (RSD) in the range of 1.65-3.85%. The intra-day and inter-day precisions were estimated to be less than 2.76% (n= 5), indicating that La(OH)3-OxMWCNTs/GCE possessed highly stability. In addition, La(OH)3-OxMWCNTs/GCE sensor showed good anti-interference ability for determination of p-NP in aqueous mixtures containing high concentrations of inorganic and organic interferents, and a decrease of oxidation peak currents by less than 3.57% relative to the initial levels indicated it possessed excellent selectivity. Therefore, La(OH)3-OxMWCNTs/GCE could be used as a fast, selective and sensitive electrochemical sensor platform for the selective determination and quantification of aqueous p-NP.


Assuntos
Técnicas Eletroquímicas/métodos , Lantânio/química , Nanocompostos/química , Nanotubos de Carbono/química , Nitrofenóis/análise , Eletrodos , Limite de Detecção , Oxirredução
14.
Ecotoxicol Environ Saf ; 201: 110872, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32559693

RESUMO

Based on a hybrid carbon nanotube composite, a novel electrochemical sensor with high sensitivity and selectivity was designed for the simultaneous determination of dopamine (DA) and uric acid (UA). The hybrid carbon nanotube composite was prepared by ultrasonic assembly of carboxylated multi-walled carbon nanotube (MWCNT-COOH) and hydroxylated single-walled carbon nanotube (SWCNT-OH). And the hybrid (MWCNT-COOH/SWCNT-OH) composite was characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FT-IR) spectroscopy. The electrochemical performances of MWCNT-COOH/SWCNT-OH composite modified glassy carbon electrode (MWCNT-COOH/SWCNT-OH/GCE) were analyzed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Under the optimum experimental conditions, the as-prepared sensor showed high sensitivity and selectivity for DA and UA. The calibration curves obtained were linear for the currents versus DA and UA concentrations in the range 2-150 µM, and limits of detection (LODs) were calculated to be 0.37 µM and 0.61 µM (signal-to-noise ratio of 3, S/N = 3), respectively. The recoveries of DA and UA in bovine serum samples at MWCNT-COOH/SWCNT-OH/GCE were in the range 96.18-105.02%, and relative standard deviations (RSDs) were 3.34-7.27%. The proposed electrochemical sensor showed good anti-interference ability, excellent reproducibility and stability, as well as high selectivity, which might provide a promising platform for determination of DA and UA.


Assuntos
Dopamina/análise , Técnicas Eletroquímicas/métodos , Nanotubos de Carbono/química , Ácido Úrico/análise , Animais , Carbono , Bovinos , Dopamina/sangue , Eletrodos , Limite de Detecção , Nanotubos de Carbono/ultraestrutura , Reprodutibilidade dos Testes , Ácido Úrico/sangue
15.
Chemosphere ; 259: 127423, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32574847

RESUMO

It is vital to synthesis hydrogen peroxide via electrochemical reduction of oxygen since it is a green process to produce oxidant with wide applications including water/wastewater treatment. In this work, fluorine (F) was employed to modify carbon nanotube (CNT), and the obtained F doped CNT (F-CNT) catalyst was used to fabricate gas diffusion electrode (GDE). It was found that F doping could improve oxygen reduction activity and H2O2 selectivity, and then enhanced the H2O2 production. After modification, F-CNT prepared with 0.6 M HF (CNT-F-0.6) had much higher H2O2 production (47.6 mg L-1) and current efficiency (89.5%) than that of CNT (29.6 mg L-1, 70.1%) at bias voltage of -1.3 V (vs SCE) and pH 7. Moreover, the high catalytic activity of CNT-F-0.6 could maintain in 5 consecutive reaction cycles. The material characterization and electrochemical test indicated that F doping had no significant effects on the surface area of CNT, but improved the defect degree of CNT. The enhanced H2O2 production performance could be ascribed to the formation of CF2 and CF3 on the surface of F-doped CNT, which rendered the potential for practical application of novel carbon catalyst for GDE.


Assuntos
Flúor/química , Nanotubos de Carbono/química , Catálise , Eletrodos , Fluoretos , Peróxido de Hidrogênio/química , Oxirredução , Oxigênio , Águas Residuárias , Purificação da Água
16.
Nanotoxicology ; 14(7): 929-946, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32538272

RESUMO

Multi-walled carbon nanotubes (MWCNTs) are known to induce pulmonary inflammatory effects through stimulating pro-inflammatory cytokine secretion from alveolar macrophages. Despite extensive studies on MWCNTs' pro-inflammatory reactivity, the understanding of molecular mechanisms involved is still incomplete. In this study, we investigated hemichannel's involvement in MWCNTs-induced macrophage IL-1ß release. Our results showed that the unmodified and COOH MWCNTs could induce ATP release and ATP-P2X7R axis-dependent IL-1ß secretion from THP-1 macrophages. By using various inhibitors, we confirmed that the MWCNTs-induced ATP release was primarily through hemichannels. EtBr dye uptake assay detected significant hemichannels opening in MWCNTs exposed THP-1 macrophages. Inhibition of hemichannels by CBX, 43Gap27, or 10Panx1 pretreatment results in decreased ATP and IL-1ß release. The addition of ATP restored the reduced IL-1ß secretion level from hemichannel inhibition. We also confirmed with five other types of MWCNTs that the induction of hemichannels by MWCNTs strongly correlates with their capacity to induce IL-1ß secretion. Taken together, we conclude that hemichannels-mediated ATP release and subsequent NLRP3 inflammasome activation through P2X7R may be one mechanism by which MWCNTs induce macrophage IL-1ß secretion. Our findings may provide a novel molecular mechanism for MWCNTs induced IL-1ß secretion.


Assuntos
Trifosfato de Adenosina/metabolismo , Conexinas/metabolismo , Interleucina-1beta/metabolismo , Macrófagos Alveolares/efeitos dos fármacos , Nanotubos de Carbono/toxicidade , Proteínas do Tecido Nervoso/metabolismo , Humanos , Inflamassomos/imunologia , Inflamassomos/metabolismo , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Nanotubos de Carbono/química , Células THP-1
17.
PLoS One ; 15(5): e0226791, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32374764

RESUMO

Over the past two decades, measurements of carbon nanotube toxicity and biodistribution have yielded a wide range of results. Properties such as nanotube type (single-walled vs. multi-walled), purity, length, aggregation state, and functionalization, as well as route of administration, greatly affect both the biocompatibility and biodistribution of carbon nanotubes. These differences suggest that generalizable conclusions may be elusive and that studies must be material- and application-specific. Here, we assess the short- and long-term biodistribution and biocompatibility of a single-chirality DNA-encapsulated single-walled carbon nanotube complex upon intravenous administration that was previously shown to function as an in-vivo reporter of endolysosomal lipid accumulation. Regarding biodistribution and fate, we found bulk specificity to the liver and >90% signal attenuation by 14 days in mice. Using near-infrared hyperspectral microscopy to measure single nanotubes, we found low-level, long-term persistence in organs such as the heart, liver, lung, kidney, and spleen. Measurements of histology, animal weight, complete blood count; biomarkers of organ function all suggest short- and long-term biocompatibility. This work suggests that carbon nanotubes can be used as preclinical research tools in-vivo without affecting acute or long-term health.


Assuntos
Materiais Biocompatíveis/farmacologia , Biomarcadores/sangue , Nanotecnologia , Nanotubos de Carbono/efeitos adversos , Animais , Materiais Biocompatíveis/efeitos adversos , Materiais Biocompatíveis/química , DNA de Cadeia Simples/química , DNA de Cadeia Simples/farmacologia , Endossomos/efeitos dos fármacos , Humanos , Fígado/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Camundongos , Nanotubos de Carbono/química , Imagem Óptica , Baço/efeitos dos fármacos , Baço/metabolismo , Distribuição Tecidual/efeitos dos fármacos
18.
Nanotoxicology ; 14(5): 711-724, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32374645

RESUMO

Prenatal particle exposure has been shown to increase allergic responses in offspring. Carbon nanotubes (CNTs) possess immunomodulatory properties, but it is unknown whether maternal exposure to CNTs interferes with offspring immune development. Here, C57Bl/6J female mice were intratracheally instilled with 67 of µg multiwalled CNTs on the day prior to mating. After weaning, tolerance and allergy responses were assessed in the offspring. Offspring of CNT-exposed (CNT offspring) and of sham-exposed dams (CTRL offspring) were intranasally exposed to ovalbumin (OVA) once weekly for 5 weeks to induce airway mucosal tolerance. Subsequent OVA sensitization and aerosol inhalation caused low or no OVA-specific IgE production and no inflammation. However, the CNT offspring presented with significantly lower OVA-specific IgG1 levels than CTRL offspring. In other groups of 5-week-old offspring, low-dose sensitization with OVA and subsequent OVA aerosol inhalation led to significantly lower OVA-specific IgG1 production in CNT compared to CTRL offspring. OVA-specific IgE and airway inflammation were non-significantly reduced in CNT offspring. The immunomodulatory effects of pre-gestational exposure to multiwalled CNTs were unexpected, but very consistent. The observations of suppressed antigen-specific IgG1 production may be of importance for infection or vaccination responses and warrant further investigation.


Assuntos
Formação de Anticorpos/efeitos dos fármacos , Antígenos/toxicidade , Hipersensibilidade/etiologia , Nanotubos de Carbono/toxicidade , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Animais , Antígenos/química , Feminino , Humanos , Hipersensibilidade/imunologia , Tolerância Imunológica/efeitos dos fármacos , Tolerância Imunológica/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Inflamação , Exposição Materna/efeitos adversos , Camundongos , Camundongos Endogâmicos BALB C , Nanotubos de Carbono/química , Ovalbumina/imunologia , Gravidez , Efeitos Tardios da Exposição Pré-Natal/imunologia
19.
Aquat Toxicol ; 224: 105504, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32450458

RESUMO

Due to their unique structure and properties, carbon nanotubes (CNTs) released into the aquatic environment can potentially influence the behavior of other coexisting pollutants, thereby altering their toxicity to aquatic organisms. In this study, the toxicities of multi-walled CNTs and three heavy metals, copper (Cu), cadmium (Cd) and zinc (Zn) were determined individually. Following this, CNTs with low concentrations (1 and 5 mg/L) were co-exposed with Cu, Cd or Zn to the microalgae Scenedesmus obliquus, to investigate the effects and underlying mechanisms of CNTs on metal toxicity. Results showed that CNTs, especially at a concentration of 5 mg/L, promoted algae growth and enhanced photosynthetic efficiency via increasing exciton trap efficiency and quantum yield for electron transport. Introduction of CNTs appeared to alleviate the adverse effects of Cu, Cd or Zn on microalgae, indicated by algae growth, total chlorophyll content and photosynthetic indices. However, these effects differed greatly for different metals, depending on both the toxicity of each metal and the exposure period (4 day and 8 day). Enhancement of photosynthesis and interference of metal uptake by CNTs, have a crucial role in the effects of CNTs on metal toxicity.


Assuntos
Água Doce/química , Metais Pesados/toxicidade , Microalgas/efeitos dos fármacos , Nanotubos de Carbono/química , Scenedesmus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Organismos Aquáticos/efeitos dos fármacos , Cádmio/toxicidade , Clorofila/metabolismo , Cobre/toxicidade , Fotossíntese/efeitos dos fármacos , Zinco/toxicidade
20.
Chemosphere ; 255: 127004, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32417516

RESUMO

A simple rapid and efficient deep eutectic solvent-based magnetic colloidal gel (DES-MCG) assisted magnetic solid-phase extraction (MSPE) method followed by high performance liquid chromatography with a diode array detector (HPLC-DAD) was established for determination of four sex hormones (including ethinylestradiol, norgestrel, megestrol acetate and medroxyprogesterone acetate) in cosmetic skin care toners. The DES-MCG with the desirable advantages of high adsorbing ability was prepared by combining choline chloride/urea deep eutectic solvent and magnetic multiwalled carbon nanotubes (MMWCNTs). The synthesized DES-MCG was characterized using fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The cosmetic skin care toners were concentrated by a rotary evaporator and the obtained solutions were further purified by DES-MCG assisted magnetic solid-phase extraction. Response surface methodology (RSM) was applied for efficient optimization of the main variables in the extraction procedure. Under the optimized conditions, method detection limits and method quantitation limits were in the range of 1.2-6.6 ng mL-1 and 4.4-26.6 ng mL-1, respectively. The recoveries of the four sex hormones in different cosmetic skin care toners ranged from 80.1% to 118.8% and the precisions were no more than 0.35%. The developed method was successfully applied for the determination of sex hormones in cosmetic skin care toners.


Assuntos
Cosméticos/química , Géis/química , Hormônios Esteroides Gonadais/análise , Pomadas/química , Extração em Fase Sólida/métodos , Solventes/química , Adsorção , Cromatografia Líquida de Alta Pressão , Cosméticos/normas , Limite de Detecção , Fenômenos Magnéticos , Nanotubos de Carbono/química , Pomadas/normas , Higiene da Pele
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