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1.
Chem Biol Interact ; 382: 110613, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37353135

RESUMO

Lung toxicity of carbon nanotubes (CNTs) is matter of concern since very long time. However, their mechanism of toxicity is still not yet well defined. In this work, the role of structural defects as organic stressors of CNTs able to trigger their potential toxicity is investigated. Four commercial CNTs, with different carbon purity grade, are morphologically characterized by transmission electron microscopy (TEM) and the relative amount of structural defects are estimated through Raman spectroscopy, by measuring the intensity ratio D/G (ID/IG). The oxidative potential of CNTs is evaluated with cytochrome-C assay and reactive oxygen species (ROS) detection. Data show that CNTs with larger amounts of structural defects (higher ID/IG ratio) induce an increased ROS generation and consequent cytotoxicity and cellular damage, shown by TEM images of CNTs-cells interaction. Raman analyses of cells exposed to CNTs point out that the spectra of the CNTs inside the cells show no differences with respect of the signal recorded for cell-free CNTs, evidencing their biopersistence in lung cells. Raman spectra cannot provide direct indication of the existence of metals as impurity. It follows that the intensity ratio ID/IG can be taken as a predictive marker of the toxicity of a given CNT.


Assuntos
Pulmão , Nanotubos de Carbono , Nanotubos de Carbono/química , Nanotubos de Carbono/toxicidade , Nanotubos de Carbono/ultraestrutura , Análise Espectral Raman , Microscopia Eletrônica de Transmissão , Humanos , Linhagem Celular , Pulmão/citologia , Pulmão/efeitos dos fármacos , Animais
2.
Bioelectrochemistry ; 151: 108391, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36805206

RESUMO

Traumatic Brain Injury, one of the significant causes of mortality and morbidity, affects worldwide and continues to be a diagnostic challenge. The most desirable and partially met clinical need is to simultaneously detect the disease-specific-biomarkers in a broad range of readily available body fluids on a single platform with a rapid, low-cost, ultrasensitive and selective device. Towards this, an array of interdigitated microelectrodes was fabricated on commercially existing low-cost single-side copper cladded printed-circuit-board substrate followed by the bioelectrodes preparation through covalent immobilization of brain injury specific biomarkers on carboxylic functionalized multi-walled carbon nanotubes embedded polypyrrole nanocomposite modified interdigitated microelectrodes. Subsequently, the immunological binding events were transduced as the normalized change in bioelectrode resistance with and without the target analyte via current-voltage analysis. As proof of concept, current-voltage responses were primarily recorded using a conventional probe station, and later, a portable handheld-electronic-readout was developed for the point-of-care application. The data compilation and analysis were carried out using the in-house developed android-based mobile app. Notably, the smartphone powered the readout through a PL-2303 serial connector, avoiding integrating power sources with the readout. Further, this technology can be adapted to other point-of-care biosensing applications.


Assuntos
Sistemas Automatizados de Assistência Junto ao Leito , Smartphone , Humanos , Biomarcadores/sangue , Lesões Encefálicas Traumáticas/diagnóstico , Microeletrodos , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Pirróis/química , Sensibilidade e Especificidade , Estudos de Viabilidade , Condutividade Elétrica , Reprodutibilidade dos Testes
3.
Int J Mol Sci ; 23(3)2022 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-35163376

RESUMO

In this study, top-down syntheses of carbon dots (CDs) from four different carbon precursors, namely, carbon nano powders, graphite, graphene, and carbon nanotubes, were carried out. Systematic study demonstrated that the optical properties and surface functionalities of the CDs were quite similar and mainly influenced by the synthesis method, while the sizes, morphologies, chemical compositions, and core structures of the CDs were heavily influenced by the carbon precursors. On the basis of these studies, the formation processes and structural models of these four top-down CDs were proposed. The cell cytotoxicity and photothermal conversion efficiency of these CDs were also carefully evaluated, demonstrating their potential applications in photothermal therapy.


Assuntos
Grafite/química , Modelos Estruturais , Nanotubos de Carbono/química , Terapia Fototérmica , Pontos Quânticos/química , Células A549 , Morte Celular , Células HaCaT , Humanos , Nanotubos de Carbono/ultraestrutura , Fenômenos Ópticos , Oxirredução , Pós , Pontos Quânticos/ultraestrutura , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Análise Espectral Raman , Eletricidade Estática , Propriedades de Superfície , Termogravimetria , Difração de Raios X
4.
Sci Rep ; 11(1): 19562, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34599218

RESUMO

Carbon nanotubes (CNTs) are cylindrical nanostructures and have unique properties, including flexibility, electrical conductivity, and biocompatibility. We focused on CNTs fabricated with the carbon nanotube yarns (cYarn) as a possible substrate promoting peripheral nerve regeneration with these properties. We bridged a 15 mm rat sciatic nerve defect with five different densities of cYarn. Eight weeks after the surgery, the regenerated axons crossing the CNTs, electromyographical findings, and muscle weight ratio of the lower leg showed recovery of the nerve function by interfacing with cYarn. Furthermore, the sciatic nerve functional index (SFI) at 16 weeks showed improvement in gait function. A 2% CNT density tended to be the most effective for nerve regeneration as measured by both histological axonal regeneration and motor function. We confirmed that CNT yarn promotes peripheral nerve regeneration by using it as a scaffold for repairing nerve defects. Our results support the future clinical application of CNTs for bridging nerve defects as an off-the-shelf material.


Assuntos
Nanotubos de Carbono , Regeneração Nervosa , Crescimento Neuronal , Traumatismos dos Nervos Periféricos/terapia , Animais , Modelos Animais de Doenças , Fenômenos Eletrofisiológicos , Feminino , Imuno-Histoquímica , Músculo Esquelético/inervação , Músculo Esquelético/patologia , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Tamanho do Órgão , Traumatismos dos Nervos Periféricos/diagnóstico , Traumatismos dos Nervos Periféricos/etiologia , Ratos , Nervo Isquiático/metabolismo , Nervo Isquiático/fisiologia , Nervo Isquiático/fisiopatologia , Tecidos Suporte/química , Resultado do Tratamento
5.
Int J Biol Macromol ; 190: 499-507, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34499956

RESUMO

Using biocompatible polymer nanofibrous conduits with a controlled drug delivery have attracted much attention for peripheral nerve regeneration. This work was aimed at preparing electrospun poly (l-lactide-co-D, l-lactide) (PLDLLA) containing multi-walled carbon nanotubes (MWCNTs) and 4-aminopyridine (4-AP)-loaded molecularly imprinted nanoparticles (MIP4-AP) as well as evaluating their performance in in vitro and in vivo assessments. After synthesis of MIP4-AP based on poly (methacrylic acid) with imprinting factor of 1.78, it was incorporated into the PLDLLA/MWCNTs nanofibers to optimize. By adjusting the process variables, the average diameter and electrical conductivity of the nanofibrous sample were 92 nm and 2870 × 10-7 S cm-1, respectively. Afterward, 4-AP release of the optimum sample showed the presence of MIP4-AP leading to initial burst release decrease and plateau level postpone up to 96 h. Moreover, the culture results of PC12 as neuroblastoma cell line on optimal PLDLLA/MWCNTs/MIP4-AP nanofibrous sample revealed the highest cell proliferation without cytotoxicity compared to neat nanofibers. Eventually, the animal model experiment exhibited that the conductive conduit based on the optimum sample was able to repair the rat's sciatic nerve after four weeks in accordance with sciatic function index and histological studies.


Assuntos
4-Aminopiridina/química , Metacrilatos/química , Impressão Molecular , Nanofibras/química , Regeneração Nervosa/fisiologia , Nervos Periféricos/fisiologia , Poliésteres/química , Engenharia Tecidual , Adsorção , Animais , Morte Celular , Proliferação de Células , Sobrevivência Celular , Condutividade Elétrica , Nanofibras/ultraestrutura , Nanopartículas/química , Nanopartículas/ultraestrutura , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Células PC12 , Ratos , Ratos Wistar
6.
Int J Mol Sci ; 22(9)2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-34063012

RESUMO

Single-walled carbon nanotubes (SWCNTs) emerge as promising novel carbon-based nanoparticles for use in biomedicine, pharmacology and precision agriculture. They were shown to penetrate cell walls and membranes and to physically interact and exchange electrons with photosynthetic complexes in vitro. Here, for the first time, we studied the concentration-dependent effect of foliar application of copolymer-grafted SWCNTs on the structural and functional characteristics of intact pea plants. The lowest used concentration of 10 mg L-1 did not cause any harmful effects on the studied leaf characteristics, while abundant epicuticular wax generation on both leaf surfaces was observed after 300 mg L-1 treatment. Swelling of both the granal and the stromal regions of thylakoid membranes was detected after application of 100 mg L-1 and was most pronounced after 300 mg L-1. Higher SWCNT doses lead to impaired photosynthesis in terms of lower proton motive force generation, slower generation of non-photochemical quenching and reduced zeaxanthin content; however, the photosystem II function was largely preserved. Our results clearly indicate that SWCNTs affect the photosynthetic apparatus in a concentration-dependent manner. Low doses (10 mg L-1) of SWCNTs appear to be a safe suitable object for future development of nanocarriers for substances that are beneficial for plant growth.


Assuntos
Cloroplastos/ultraestrutura , Nanotubos de Carbono/química , Fotossíntese , /ultraestrutura , Folhas de Planta/anatomia & histologia , Dióxido de Carbono/metabolismo , Carotenoides/metabolismo , Permeabilidade da Membrana Celular , Clorofila/metabolismo , Fluorescência , Nanotubos de Carbono/ultraestrutura , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/ultraestrutura , Prótons , Tilacoides/metabolismo , Fatores de Tempo , Xantofilas/metabolismo
7.
Molecules ; 26(10)2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-34068851

RESUMO

Solubilization of carbon nanotubes (CNTs) is a fundamental technique for the use of CNTs and their conjugates as nanodevices and nanobiodevices. In this work, we demonstrate the preparation of CNT suspensions with "green" detergents made from coconuts and bamboo as fundamental research in CNT nanotechnology. Single-walled CNTs (SWNTs) with a few carboxylic acid groups (3-5%) and pristine multi-walled CNTs (MWNTs) were mixed in each detergent solution and sonicated with a bath-type sonicator. The prepared suspensions were characterized using absorbance spectroscopy, scanning electron microscopy, and Raman spectroscopy. Among the eight combinations of CNTs and detergents (two types of CNTs and four detergents, including sodium dodecyl sulfate (SDS) as the standard), SWNTs/MWNTs were well dispersed in all combinations except the combination of the MWNTs and the bamboo detergent. The stability of the suspensions prepared with coconut detergents was better than that prepared with SDS. Because the efficiency of the bamboo detergents against the MWNTs differed significantly from that against the SWNTs, the natural detergent might be useful for separating CNTs. Our results revealed that the use of the "green" detergents had the advantage of dispersing CNTs as well as SDS.


Assuntos
Detergentes/química , Nanotubos de Carbono/química , Centrifugação , Nanotubos de Carbono/ultraestrutura , Suspensões
8.
J Biomed Mater Res A ; 109(10): 1869-1880, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33797196

RESUMO

Carbon nanotubes (CNTs) have attracted significant interest for various applications owing to their superior physicochemical properties. The unzipping of multi-walled carbon nanotubes was accomplished by strong acid treatment. The solution of unzipped carbon nanotubes (u-CNTs) was homogeneous and stable. The u-CNTs were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. The dimensions and morphologies of the synthesized u-CNTs were examined by transmission electron microscopy and scanning electron microscopy. The u-CNTs exhibited increased zeta potential and diameter compared with pure CNTs. A decrease in the thermal stability was observed in the u-CNTs compared with pure CNTs. The u-CNTs exhibited better biocompatibility than pure CNTs in the presence of bone marrow-derived mesenchymal stem cells, showing improved biocompatibility. The u-CNT-treated media generated lower amounts of reactive oxygen species than pure CNTs. Enhanced mineralization was observed in the u-CNT-treated groups compared with the pure CNTs and the control, indicating its better osteogenic potential. The upregulation of osteogenic-associated gene markers in u-CNT groups compared with pure CNTs confirms their superior osteogenic potential. Thus, u-CNTs are potential candidates for tissue engineering applications, especially bone tissue.


Assuntos
Nanotubos de Carbono/química , Osteogênese , Engenharia Tecidual , Fosfatase Alcalina/metabolismo , Animais , Calcificação Fisiológica , Morte Celular , Sobrevivência Celular , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Nanotubos de Carbono/ultraestrutura , Espécies Reativas de Oxigênio/metabolismo , Temperatura , Difração de Raios X
9.
Molecules ; 26(6)2021 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-33805628

RESUMO

Doxorubicin (DOX), a recognized anticancer drug, forms stable associations with carbon nanotubes (CNTs). CNTs when properly functionalized have the ability to anchor directly in cancerous tumors where the release of the drug occurs thanks to the tumor slightly acidic pH. Herein, we study the armchair and zigzag CNTs with Stone-Wales (SW) defects to rank their ability to encapsulate DOX by determining the DOX-CNT binding free energies using the MM/PBSA and MM/GBSA methods implemented in AMBER16. We investigate also the chiral CNTs with haeckelite defects. Each haeckelite defect consists of a pair of square and octagonal rings. The armchair and zigzag CNT with SW defects and chiral nanotubes with haeckelite defects predict DOX-CNT interactions that depend on the length of the nanotube, the number of present defects and nitrogen doping. Chiral nanotubes having two haeckelite defects reveal a clear dependence on the nitrogen content with DOX-CNT interaction forces decreasing in the order 0N > 4N > 8N. These results contribute to a further understanding of drug-nanotube interactions and to the design of new drug delivery systems based on CNTs.


Assuntos
Antineoplásicos/administração & dosagem , Doxorrubicina/administração & dosagem , Portadores de Fármacos/administração & dosagem , Sistemas de Liberação de Medicamentos , Nanotubos de Carbono/química , Antineoplásicos/química , Simulação por Computador , Doxorrubicina/química , Portadores de Fármacos/química , Composição de Medicamentos/métodos , Humanos , Simulação de Dinâmica Molecular , Estrutura Molecular , Nanotecnologia , Nanotubos de Carbono/ultraestrutura
10.
Int J Mol Sci ; 22(6)2021 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-33805783

RESUMO

In anaerobic bioreactors, the electrons produced during the oxidation of organic matter can potentially be used for the biological reduction of pharmaceuticals in wastewaters. Common electron transfer limitations benefit from the acceleration of reactions through utilization of redox mediators (RM). This work explores the potential of carbon nanomaterials (CNM) as RM on the anaerobic removal of ciprofloxacin (CIP). Pristine and tailored carbon nanotubes (CNT) were first tested for chemical reduction of CIP, and pristine CNT was found as the best material, so it was further utilized in biological anaerobic assays with anaerobic granular sludge (GS). In addition, magnetic CNT were prepared and also tested in biological assays, as they are easier to be recovered and reused. In biological tests with CNM, approximately 99% CIP removal was achieved, and the reaction rates increased ≈1.5-fold relatively to the control without CNM. In these experiments, CIP adsorption onto GS and CNM was above 90%. Despite, after applying three successive cycles of CIP addition, the catalytic properties of magnetic CNT were maintained while adsorption decreased to 29 ± 3.2%, as the result of CNM overload by CIP. The results suggest the combined occurrence of different mechanisms for CIP removal: adsorption on GS and/or CNM, and biological reduction or oxidation, which can be accelerated by the presence of CNM. After biological treatment with CNM, toxicity towards Vibrio fischeri was evaluated, resulting in ≈ 46% detoxification of CIP solution, showing the advantages of combining biological treatment with CNM for CIP removal.


Assuntos
Ciprofloxacina/metabolismo , Elétrons , Nanopartículas de Magnetita/química , Nanotubos de Carbono/química , Esgotos/microbiologia , Poluentes Químicos da Água/metabolismo , Adsorção , Aliivibrio fischeri/efeitos dos fármacos , Aliivibrio fischeri/crescimento & desenvolvimento , Anaerobiose/fisiologia , Biodegradação Ambiental , Reatores Biológicos , Ciprofloxacina/isolamento & purificação , Humanos , Nanopartículas de Magnetita/ultraestrutura , Methanobacterium/metabolismo , Methanobrevibacter/metabolismo , Methanosarcinales/metabolismo , Methanospirillum/metabolismo , Testes de Sensibilidade Microbiana , Nanotubos de Carbono/ultraestrutura , Oxirredução , Poluentes Químicos da Água/isolamento & purificação
11.
ACS Appl Mater Interfaces ; 13(13): 15572-15583, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33760608

RESUMO

High-performance flexible strain sensors are urgently needed with the rapid development of wearable intelligent electronics. Here, a bifiller of carbon nanotubes (CNTs) and graphene (GR) for filling flexible porous polydimethylsiloxane (CNT-GR/PDMS) nanocomposites is designed and prepared for strain-sensing applications. The typical microporous structure was successfully constructed using the Soxhlet extraction technique, and the connected CNTs and GR constructed a perfect three-dimensional conductive network in the porous skeleton. As a result, the stretchability and sensitivity of the CNT-GR/PDMS-based strain sensors were well regulated based on the porous structure and the typical synergistic conductive network. Based on the destruction effect of the brittle synergistic conductive network located in the outer and inner layers of the cell skeleton and the contact effect between adjacent cells in different strain ranges, the prepared CNTs-GR/PDMS-based strain sensor exhibited superior gauge factors of 182.5, 45.6, 70.2, and 186.5 in the 0-3, 3-57, 57-90, and 90-120% strain regions, respectively. In addition, this material also exhibited an ultralow detection limit (0.5% strain), a fast response time (60 ms), good stability and durability (10,000 cycles), and frequency-/strain-dependent sensing performances, making it active for the detection of various external environments. Finally, the prepared porous CNTs-GR/PDMS-based strain sensor was attached to the skin to detect various human motions, such as wrist bending, finger bending, elbow bending, and knee bending, thereby demonstrating wide application prospects in smart wearable devices.


Assuntos
Dimetilpolisiloxanos/química , Grafite/química , Nanotubos de Carbono/química , Dispositivos Eletrônicos Vestíveis , Fenômenos Biomecânicos , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Condutividade Elétrica , Humanos , Nanotubos de Carbono/ultraestrutura , Porosidade , Estresse Mecânico
12.
Int J Biol Macromol ; 180: 590-598, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33711373

RESUMO

Myocardial infarction of cardiomyocytes is a leading cause of heart failure (HF) worldwide. Since heart has very limited regeneration capacity, cardiac tissue engineering (TE) to produce a bioactive scaffold is considered. In this study, a series of polyurethane solutions (5-7%wt) in aqueous acetic acid were prepared using electrospinning. A variety of Polyurethane (PU)/Chitosan (Cs)/carbon nanotubes (CNT) composite nanofibrous scaffolds with random and aligned orientation were fabricated to structurally mimic the extracellular matrix (ECM). Electrospun nanofibers were then characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), water contact angle, degradation studies, tensile tests, electrical resistance measurement and cell viability assay. The biocompatibility of electrospun random and aligned nanofibrous scaffolds with H9C2 Cells was confirmed. The results revealed that fabricated PU/Cs/CNT composite nanofibrous scaffolds were electro-conductive and aligned nanofibers could be considered as promising scaffolds with nano-scale features for regeneration of infarcted myocardium.


Assuntos
Quitosana/química , Miócitos Cardíacos/citologia , Nanofibras/química , Poliuretanos/química , Engenharia Tecidual/métodos , Tecidos Suporte/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Microscopia Eletrônica de Varredura/métodos , Microscopia Eletrônica de Transmissão , Nanofibras/ultraestrutura , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Ratos , Análise Espectral Raman , Difração de Raios X
13.
Molecules ; 26(4)2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33671928

RESUMO

Metal organic framework (MOF)-derived carbon nanostructures (MDC) synthesized by either calcinations or carbonization or pyrolysis are emerging as attractive materials for a wide range of applications like batteries, super-capacitors, sensors, water treatment, etc. But the process of transformation of MOFs into MDCs is time-consuming, with reactions requiring inert atmospheres and reaction time typically running into hours. In this manuscript, we report the transformation of 1,4-diazabicyclo[2.2.2]octane, (DABCO)-based MOFs into iron nitride nanoparticles embedded in nitrogen-doped carbon nanotubes by simple, fast and facile microwave pyrolysis. By using graphene oxide and carbon fiber as microwave susceptible surfaces, three-dimensional nitrogen-doped carbon nanotubes vertically grown on reduced graphene oxide (MDNCNT@rGO) and carbon fibers (MDCNT@CF), respectively, were obtained, whose utility as anode material in sodium-ion batteries (MDNCNT@rGO) and for EMI (electromagnetic interference) shielding material (MDCNT@CF) is reported.


Assuntos
Carbono/química , Fontes de Energia Elétrica , Fenômenos Eletromagnéticos , Estruturas Metalorgânicas/química , Nanoestruturas/química , Nitrogênio/química , Sódio/química , Fibra de Carbono/química , Eletrodos , Íons , Nanoestruturas/ultraestrutura , Nanotubos de Carbono/ultraestrutura , Espectroscopia Fotoeletrônica , Pirólise , Análise Espectral Raman , Difração de Raios X
14.
J Chromatogr A ; 1639: 461921, 2021 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-33524931

RESUMO

Present study described a sensitive and efficient method for determination of heterocyclic aromatic hydrocarbons using multiwalled carbon nanotubes modified magnetic polyamido-amine dendrimers (MNPs@PAMAM-Gn@MWCNTs) as adsorbent for magnetic solid-phase extraction (MSPE) coupled with gas chromatography-triple quadrupole mass spectrometer (GC-MS/MS). Some pivotal parameters including PAMAM generation, adsorbent dosage, adsorption time, elution time and volume, pH and humic acid concentration were investigated to achieve the best adsorption efficiencies. Under the optimal conditions, 7-methylquinoline, dibenzothiophene and carbazole had good linearity in the concentration range of 0.005-20 µg L - 1, 9-methylcarbazole, 4-methyldibenzothiophene and 4,6-dimethyl dibenzothiophene had good linearity in the concentration range of 0.001-20 µg L - 1. All the correlation coefficients were higher than 0.996. The detection limits of the targets were in the range of 2.2 × 10-4-1.8 × 10-3 µg L - 1 with precisions less than 8.28% (n = 6). The enrichment factors were in the range of 141-147. The spiked recoveries were in the range of 87.0%-115.1% (n = 3). These results indicated that the method could be a reliable alternative tool for monitoring trace heterocyclic aromatic hydrocarbons in environmental water samples.


Assuntos
Aminas/química , Dendrímeros/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Fenômenos Magnéticos , Nanotubos de Carbono/química , Nylons/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Extração em Fase Sólida/métodos , Adsorção , Nanotubos de Carbono/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/análise , Difração de Raios X
15.
ACS Appl Mater Interfaces ; 13(4): 5486-5497, 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33491443

RESUMO

Flexible paper-based sensors may be applied in numerous fields, but this requires addressing their limitations related to poor thermal and water resistance, which results in low service life. Herein, we report a paper-based composite sensor composed of carboxylic carbon nanotubes (CCNTs) and poly-m-phenyleneisophthalamide (PMIA), fabricated by a facile papermaking process. The CCNT/PMIA composite sensor exhibits an ability to detect pressures generated by various human movements, attributed to the sensor's conductive network and the characteristic "mud-brick" microstructure. The sensor exhibits the capability to monitor human motions, such as bending of finger joints and elbow joints, speaking, blinking, and smiling, as well as temperature variations in the range of 30-90 °C. Such a capability to sensitively detect pressure can be realized at different applied frequencies, gradient sagittas, and multiple twists with a short response time (104 ms) even after being soaked in water, acid, and alkali solutions. Moreover, the sensor demonstrates excellent mechanical properties and hence can be folded up to 6000 times without failure, can bear 5 kg of load without breaking, and can be cycled 2000 times without energy loss, providing a great possibility for a long sensing life. Additionally, the composite sensor shows exceptional Joule heating performance, which can reach 242 °C in less than 15 s even when powered by a low input voltage (25 V). From the perspective of industrialization, low-cost and large-scale roll-to-roll production of the paper-based sensor can be achieved, with a formed length of thousands of meters, showing great potential for future industrial applications as a wearable smart sensor for detecting pressure and temperature, with the capability of electric heating.


Assuntos
Nanotubos de Carbono/química , Papel , Fenilenodiaminas/química , Ácidos Ftálicos/química , Polímeros/química , Dispositivos Eletrônicos Vestíveis , Técnicas Biossensoriais/instrumentação , Condutividade Elétrica , Humanos , Monitorização Fisiológica/instrumentação , Movimento (Física) , Nanotubos de Carbono/ultraestrutura
16.
Molecules ; 26(3)2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33498976

RESUMO

Molecular magnets attached to carbon nanotubes (CNT) are being studied as potential candidates for developing spintronic and quantum technologies. However, the functionalization routes used to develop these hybrid systems can drastically affect their respective physiochemical properties. Due to the complexity of this systems, little work has been directed at establishing the correlation between the degree of functionalization and the magnetic character. Here, we demonstrate the chemical functionalization degree associated with molecular magnet loading can be utilized for controlled tuning the magnetic properties of a CNT-lanthanide hybrid complex. CNT functionalization degree was evaluated by interpreting minor Raman phonon modes in relation to the controlled reaction conditions. These findings were exploited in attaching a rare-earth-based molecular magnet (Gd-DTPA) to the CNTs. Inductively coupled plasma mass spectrometry, time-of-flight secondary ion mass spectrometry and super conducting quantum interference device (SQUID) measurements were used to elucidate the variation of magnetic character across the samples. This controlled Gd-DTPA loading on the CNT surface has led to a significant change in the nanotube intrinsic diamagnetism, showing antiferromagnetic coupling with increase in the Weiss temperature with respect to increased loading. This indicates that synthesis of a highly correlated spin system for developing novel spintronic technologies can be realized through a carbon-based hybrid material.


Assuntos
Elementos da Série dos Lantanídeos/química , Imãs/química , Nanotubos de Carbono/química , Gadolínio DTPA/química , Fenômenos Magnéticos , Microscopia Eletrônica de Transmissão , Nanotubos de Carbono/ultraestrutura , Espectrometria de Massa de Íon Secundário , Análise Espectral Raman
17.
J Chromatogr A ; 1639: 461891, 2021 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-33513471

RESUMO

The retention behavior of a series of acidic drugs, namely ketoprofen (KET), naproxen (NAP), diclofenac (DIC), and ibuprofen (IBU), on the heat-resisting ZORBAX 300SB-C18 column, was studied thermodynamically using high-temperature liquid chromatography (HTLC). A perfect correlation of the compounds' lipophilicity and the calculated thermodynamic indicators evidenced its contribution to the retention behavior. Besides, the steric fitting has a subsidiary effect on IBU retention. Isocratic HTLC separation of the four compounds was achieved using an aqueous mobile phase containing 30% acetonitrile-0.2% acetic acid-0.2% triethylamine at 60 °C. This method has been utilized to monitor the adsorption efficiency of multiwalled carbon nanotubes (MWCNTs) for the removal of the four NSAIDs from water. Different variables affecting the remediation process have been optimized such as the time of contact, pH, ionic strength, temperature, and the mass of MWCNTs. The kinetics and thermodynamics of the adsorption were investigated. The adsorption was evidenced to take place via pseudo-second-order kinetics and the intraparticle diffusion is the rate-controlling step. The thermodynamic investigation showed that the adsorption process is exothermic and enthalpy-driven, and the adsorption is more extensive at a lower temperature. The MWCNTs showed excellent adsorption efficiency of about 76.4 to 97.6% at the optimum conditions. The obtained results are promising and encouraging for the full-scale application of MWCNTs for remediation of NSAIDs-related water pollution. The green analytical chemistry metric "AGREE" and the analytical eco-scale score tool confirmed that the developed protocol is greener and more favorable to the environment and user than most of the reported literature.


Assuntos
Cromatografia Líquida/métodos , Temperatura Alta , Nanotecnologia/métodos , Nanotubos de Carbono/química , Preparações Farmacêuticas/isolamento & purificação , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Anti-Inflamatórios não Esteroides/isolamento & purificação , Difusão , Concentração de Íons de Hidrogênio , Cinética , Nanotubos de Carbono/ultraestrutura , Concentração Osmolar , Reprodutibilidade dos Testes , Soluções , Termodinâmica , Fatores de Tempo
18.
Molecules ; 26(2)2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33440910

RESUMO

Graphene and phospholipids are widely used in biosensing and drug delivery. This paper studies the mechanical and electronic properties of a composite based on two graphene flakes and dipalmitoylphosphatidylcholine (DPPC) phospholipid molecules located between them via combination of various mathematical modeling methods. Molecular dynamics simulation showed that an adhesion between bilayer graphene and DPCC increases during nanoindentation of the composite by a carbon nanotube (CNT). Herewith, the DPPC molecule located under a nanotip takes the form of graphene and is not destroyed. By the Mulliken procedure, it was shown that the phospholipid molecules act as a "buffer" of charge between two graphene sheets and CNT. The highest values of electron transfer in the graphene/DPPC system were observed at the lower indentation point, when the deflection reached its maximum value.


Assuntos
1,2-Dipalmitoilfosfatidilcolina/química , Grafite/química , Nanocompostos/química , Elétrons , Simulação de Dinâmica Molecular , Nanocompostos/ultraestrutura , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Estresse Mecânico
19.
J Chromatogr A ; 1638: 461888, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33482614

RESUMO

Lead contamination in drinking and natural water has reached alarming concentrations, thus necessitating the development of accurate and rapid determination systems for Pb(II) in aqueous systems. Two hyphenated flow injection-solid phase extraction- FAAS (FI-SPE-FAAS) systems using oxidized and m-phenylenediamine functionalized multiwalled carbon nanotubes for Pb(II) preconcentration from industrially contaminated real water samples have been proposed. The chemical and hydrodynamic parameters affecting Pb(II) sorption/desorption were optimized. The effect of common interfering ions in water was also studied. Different figures of merit such as preconcentration factor (> 70), detection limit (≤ 1.5 µg L-1), and relative standard deviation (≤ 1.3%) were achieved at the preconcentration time of 120 s for both the preconcentration systems. The method was applied to industrially contaminated real water samples and the spike recovery tests were carried out using standard Pb(II) solution traceable to NIST. The proposed method was validated using standard reference material 1640a supplied by NIST Gaithersburg, MD, USA.


Assuntos
Chumbo/análise , Nanotubos de Carbono/química , Espectrofotometria Atômica/métodos , Adsorção , Concentração de Íons de Hidrogênio , Nanotubos de Carbono/ultraestrutura , Padrões de Referência , Reprodutibilidade dos Testes , Reologia , Extração em Fase Sólida , Espectroscopia de Infravermelho com Transformada de Fourier , Água/análise , Poluentes Químicos da Água/análise
20.
ACS Appl Mater Interfaces ; 13(3): 3701-3712, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33406818

RESUMO

Carbon nanohorns (CNHs), a type of nanocarbon, have been studied for the application of drug delivery systems (DDSs) because they are easily functionalized, support bone regeneration, can be used to perform photohyperthermia, have low toxicity, and are easily phagocytosed by macrophages. To take advantage of these features of CNHs, we developed a DDS for the local treatment of bone metastasis by loading the antibone resorption drug ibandronate (IBN) onto CNHs. The poor adsorption of IBN onto CNHs due to the weak hydrophilic-hydrophobic interaction was overcome by using calcium phosphates (CaPs) as mediators. In the fabrication process, we used oxidized CNH (OxCNH), which is less hydrophobic, onto which IBN was coprecipitated with CaP from a labile supersaturated CaP solution. OxCNH-CaP-IBN composite nanoparticles exerted stronger cell-suppressive effects than OxCNH and IBN in both murine macrophages (RAW264.7 cells) and osteoclasts (differentiated from RAW264.7 cells). OxCNH-CaP-IBN composite nanoparticles were efficiently phagocytosed by macrophage cells, where they specifically accumulated in lysosomes. The stronger cell-suppressive effects were likely due to intracellular delivery of IBN, i.e., the release of IBN from OxCNH-CaP-IBN composite nanoparticles via dissociation of CaP in the acidic environment of lysosomes. Our findings suggest that OxCNH-CaP-IBN composite nanoparticles are potentially useful for the local treatment of metastatic bone destruction.


Assuntos
Conservadores da Densidade Óssea/farmacologia , Portadores de Fármacos/química , Ácido Ibandrônico/farmacologia , Macrófagos/efeitos dos fármacos , Nanotubos de Carbono/química , Osteoclastos/efeitos dos fármacos , Animais , Conservadores da Densidade Óssea/administração & dosagem , Fosfatos de Cálcio/química , Ácido Ibandrônico/administração & dosagem , Camundongos , Nanotubos de Carbono/ultraestrutura , Células RAW 264.7
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