Functionalized Single-Wall Carbon Research Articles

Improving Antibacterial Activity of Methicillin by Conjugation to Functionalized Single-Wall Carbon Nanotubes Against MRSA

Improving Antibacterial Activity of Methicillin by Conjugation to Functionalized Single-Wall Carbon Nanotubes Against MRSA

Physical Characterization and Material Properties of Epoxy Matrix Nanocomposites Containing Functionalized Single-Walled Carbon Nanotubes

Physical Characterization and Material Properties of Epoxy Matrix Nanocomposites Containing Functionalized Single-Walled Carbon Nanotubes

Room Temperature NO<sub>2</sub> Gas Sensor Based on Functionalized Carbon Nanotubes /Nickel Oxide Nanoparticles

Functionalized-multi wall carbon nanotubes (F-MWCNTs) and functionalized-single wall carbon nanotubes (F-SWCNTs) were well enhanced using NiO Nanoparticles. The sensor device consisted of a film of sensitive material (F-MWCNTs/ Nickel oxide nanoparticles) and (F-SWCNTs/ Nickel oxide nanoparticles) deposited by drop casting on n-type porous silicon substrate. The two sensors perform high sensitivity to NO2 gas at particular temperatures. The analysis indicated that the (F-MWCNTs/NiONPs) have a better performance than (F-SWCNTs/NiONPs). The F-SWCNTs/NiONPs gas sensor shows high sensitivity (18.2 %) at RT with response time 16 sec, while F-MWCNTs/NiONPs gas sensor show better sensitivity (45 %) at RT with response time 26 sec. The device shows a very reproducible sensor performance, with high repeatability, complete recovery and adequate response. A demonstration of the improvement in sensing of NO2 gas using NiO-functionalized nanotubes is provided.

Functional Single-Walled Carbon Nanotubes for Anion Sensing.

We report an anion-sensing platform wherein conductance changes are triggered by chemical interactions between selectors and anions. The selector design incorporates both a cationic moiety (i.e., pyridinium) and a thiourea-based dual-hydrogen-bond donor. Anion binding by a model selector (2) was studied using 1H NMR and UV-vis titrations, which reveal a binding strength toward acetate ions (AcO-) followed by Cl- > Br- > NO3-. These studies reveal that selector 2 is deprotonated upon addition of AcO-, whereas it undergoes hydrogen bonding associated with Cl-, Br-, and NO3-. The cationic pyridinium moiety improves anion binding affinity by lowering the pKa value of selector 2 and enhancing the hydrogen-bond donor capability as confirmed by spectroscopic titrations and DFT calculations. The selector is covalently attached to poly(4-vinylpyridine) (P4VP), which wraps single-walled carbon nanotubes (SWCNTs) (i.e., P4VP-2-SWCNT) to transduce an electrical signal. As a result, continuous anion sensing was achieved with high sensitivity represented by a normalized resistance change of 101.9 ± 10.3% toward 16.7 mM AcO-, whereas negligible sensitivity was observed toward Cl-, Br-, and NO3-. The sensitivity transition was attributed to the internal charge transfer of 2 by deprotonation of the thiourea proton upon addition of AcO-.

Bioinspired Ternary Artificial Nacre Graphene Oxide/Carboxyl Functionalized Single-Walled Carbon Nanotubes/Konjac Glucomannan with Enhanced Mechanical Properties.

Inspired by the nacre layered multistage structure and high toughness and strength of the unity of mechanical properties, a graphene oxide/carboxyl functionalized single-walled carbon nanotubes/konjac glucomannan (GO-SC-KGM) nanocomposite is successfully fabricated through a vacuum filtration method for the first time. The GO nanosheets with carboxyl and hydroxyl groups, SC with carboxyl groups, and the KGM molecule chains with abundant hydroxyl groups could easily form hydrogen bonding networks, resulting in a strong interface interaction. The tensile strength of prepared GO-SC-KGM nanocomposites reaches 311.4 ± 9.2 MPa. At the same time, it can maintain toughness up to 11.1 ± 0.5 MJ m-3. Its strength and toughness are much higher than nacres and other nacre-like GO-base composites. Thus, this kind of SC enhances high tensile strength and toughness, and the bioinspired nanocomposite exhibits promising potential applications for food packaging, aerospace, tissue engineering, or as a replacement for conventional chemical synthetic organic based materials.

Experimental observation of the far field diffraction patterns of functionalization single and multi-walled carbon nanotubes using nonlinear diffraction technique

Nonlinear diffraction pattern can be induced by focusing CWlaser into a thin quartzes cuvette containing nanofluid. The numberof revealed pattern rings indicates to the nonlinear behavior of fluid.Here, the nonlinear refractive index of each of functionalized singlewall carbon nanotube (F-SWCNTs) suspention and multi wall carbonnanotube (F-MWCNTs) suspention have been investigatedexperimentally .Each of CNTs suspention was at volume fraction of13×10−5 and 6×10−5. Moreover the laser source at wavelength of473 nm was used. The results show that SWCNTs suspentionpossesses higher nonlinearty than other at the same volume fraction

Raman spectroscopy on 3-D acid-functional single-walled carbon nanotubes for flexible transparent-conducting films deposited with vacuum-filtration and dip-coating

This research investigated the Raman spectra on 3-D functional single-walled carbon nanotubes (SWCNTs) which were deposited on polycarbonate (PC) with dip-coating as flexible transparent-conducting film for fast and large area deposition. The pre-acidification was done by using of sulfuric acid to form the 3-D carboxylic acid (COOH) functionalization on the SWCNTs collected by vacuum filtration. The analysis of Raman spectra could explicate the pre-purity saturation of sulfuric by the area ratios of G/D. Simultaneously the G+ peak appeared the blue shift with the acid functionalization inside SWCNTs and G− peak suggested the good dispersion of SWCNTs by its vibration along the circumferential direction, so the area ratio of the G+/G− could explain the dispersion level of the acid-functional SWCNTs. However, the best pre-acid temperature and time were 120 °C and 24 h, respectively, and the sheet resistance of SWCNTs/PC flexible film could be <500 Ω/sq at transmittance above 70%.

Functional single-walled carbon nanotubes 'CAR' for targeting dopamine delivery into the brain of parkinsonian mice.

Current treatments for Parkinson's disease (PD) are limited, partly due to the difficulties posed by the blood brain barrier (BBB) when delivering drugs to the brain. Herein, we explore the feasibility and efficacy of functional single-walled carbon nanotubes 'CAR' (SWCNT-PEGs-Lf) which carry and target-deliver dopamine (DA) to the brain in PD mice for treatment. SWCNTs can penetrate the cell-membrane remarkably, with the characteristics including high drug-loading and pH-dependent therapeutic unloading capacities. It has been reported that polyethylene glycol (PEG)-coated SWCNTs could increase the circulation time and thus prolong the concentration gradient of SWCNTs to the brain. Besides, an obvious lactoferrin-nanoparticle (Lf-NP) accumulation in the striatum, wherein the pharmacological target site of PD has been reported, a dual modification of PEG and Lf onto SWCNTs was applied and thus a specific 'CAR' to carry DA. The results from in vitro studies demonstrate that with 20 mol L-1 DA loaded onto SWCNT-polyethylene glycol (PEGs) in addition to 100 μmol L-1 6-hydroxydopamine (6-OHDA), the activity of PC12 cells increases significantly (p < 0.05), and that the lactate dehydrogenase (LDH) levels and reactive oxygen species (ROS) content also significantly decrease (p < 0.01). Furthermore, the levels of oxidative stress, tumor necrosis factor (TNF)-α and interleukin (IL)-1β are all reduced significantly in PD mice and the CAR-25 mg kg-1 DA group in comparison with that in 6-OHDA-lesioned mice with saline and 6-OHDA-lesioned mice, as well as the Tyrosine hydroxylase-immunoreactive (TH-ir) density increased (p < 0.01). The toxicity of CAR was in vitro and in vivo investigated, showing that the safe dose of SWCNT-PEG exposure to PC12 cells was 6.25 μg μl-1 or lower with a higher metabolic activity in comparison with that in the control group and the safe dose of CAR in the mice experiments was 3.25 mg kg-1 or less, given by intraperitoneal injection with a lower level of oxidative stress and inflammatory responses in comparison with that in the control group. This study suggests that 25 mg kg-1 DA loaded onto 3.25 mg kg-1 CAR can alleviate the oxidative stress and inflammatory responses in parkinsonian mice and increase the TH-ir density in the striatum.

Functional Single-Walled Carbon Nanotubes and Nanoengineered Networks for Organic- and Perovskite-Solar-Cell Applications.

Carbon nanotubes have a variety of remarkable electronic and mechanical properties that, in principle, lend them to promising optoelectronic applications. However, the field has been plagued by heterogeneity in the distributions of synthesized tubes and uncontrolled bundling, both of which have prevented nanotubes from reaching their full potential. Here, a variety of recently demonstrated solution-processing avenues is presented, which may combat these challenges through manipulation of nanoscale structures. Recent advances in polymer-wrapping of single-walled carbon nanotubes (SWNTs) are shown, along with how the resulting nanostructures can selectively disperse tubes while also exploiting the favorable properties of the polymer, such as light-harvesting ability. New methods to controllably form nanoengineered SWNT networks with controlled nanotube placement are discussed. These nanoengineered networks decrease bundling, lower the percolation threshold, and enable a strong enhancement in charge conductivity compared to random networks, making them potentially attractive for optoelectronic applications. Finally, SWNT applications, to date, in organic and perovskite photovoltaics are reviewed, and insights as to how the aforementioned recent advancements can lead to improved device performance provided.

Preparation of Diaminedicarboxyplatinum (II) Functionalized Single-Wall Carbon Nanotube via Bingel Reaction as a Novel Cytotoxic Agent.

Carbon nanotubes have unique properties like high stability, high surface to mass ratio and so on which make them suitable for medicinal purpose applications. Treatment of cancer by organoplatinum agents like Cisplatin has become unresponsive in most cases due to low distribution of drug in biological fluids, inability of drug to cross cellular membranes and low stability in biological environments. Recently, carbon nanotubes (CNT) have stimulated much interest to overcome these limitations. ‎‎ Herein, we report the preparation of single-wall carbon nanotube functionalized by diaminedicarboxyplatinum (II) as an analogy of SWCNT-based Carboplatin. Functionalization was started by cyclopropanation through Bingel reaction and by use of diethylmalonate to yield cyclopropane-1,1-dicarboxy ethyl ester. Final product was obtained by hydrolysis of ester group and then chelation of platinum (IV) by dicarboxylate groups on the surface of SWCNT. Raman and Fourier transform -Infrared ‎spectroscopy (IR), ‎Thermogravimetric ‎analysis ‎(TGA) and energy dispers‎ive X-ray‎spectroscopy ‎(EDAX) truly showed and confirmed the presence of the platinum (II) complex on the side wall of SWCNT. Cytotoxicity evaluation of the functionalized-SWCNTs on HeLa cells showed its higher anticancer ability than Cisplatin as indicated by IC50 value of 13 µg/mL.

Effects of different functionalization schemes on the interfacial strength of carbon nanotube polyethylene composite

The mechanical performance of carbon nanotube (CNT) reinforced polymer composites is primarily controlled by the dispersive capacity and interfacial shear strength of CNTs in polymer matrices. CNT functionalizations will improve dispersion and strengthen interfacial bonding of CNTs in matrices. To understand the effects of different functionalization schemes on the interfacial strength of CNT-polymer composites, pullout of the covalent, noncovalent, and mixed functionalized single-walled carbon nanotube (SWCNT) from polyethylene (PE) matrix was simulated by using molecular dynamics, respectively. The results show that the SWCNT-PE interfacial shear strength is significantly improved by SWCNT functionalizations, particularly by mixed functionalization.

Platinum Decorated Nafion Functionalized Single-Wall Carbon Nanohorns As Catalyst for Proton Exchange Membrane Fuel Cell Applications

Electrode structure plays an important role in the performance of proton exchange membrane fuel cells. To get high electrochemical active area in the electrode, perfluorosulfonate-ionomer is loaded in stage wise. Single-wall carbon nanohorns (SWCNHs) are synthesized by DC arc-discharge method in Helium atmosphere and these synthesized SWCNHs were functionalized with Nafion. Platinum was reduced onto Nafion functionalized SWCNHs through colloidal method. Pt/Nafion-SWCNHs catalysts were prepared by varying deposition times. Detailed characterization of the catalyst was carried out using Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy (IR), and Thermo Gravimetric Analysis (TGA). TEM of Pt decorated SWCNHs revealed uniformly dispersed Pt nano particles with an average particle size of 3 nm in the SWCNHs. IR studies of catalyst confirm the presence of Nafion on Pt/Nafion-SWCNHs. Nafion membrane and Pt/Nafion-SWCNHs catalyst were used to construct fuel cell in decal method and tested in fuel cell testing facility. Cyclic voltammetry tests of the catalyst also confirm the high electrochemical active area of the catalyst. Pt reduction onto Nafion functionalized SWCNHs leads to an increase in electrochemically active surface area. High platinum utilization due to increased electrochemical surface area with efficient SWCNHs support of Pt/Nafion-SWCNHs catalyst makes it a promising electrocatalyst for fuel cells.

Fabrication of nano-TiO2/carbon nanotubes and nano-TiO2/nanocarbon black on alkali hydrolyzed polyester producing photoactive conductive fabric

In this paper, the alkali hydrolyzed polyester fabric was treated with functional single-wall and multi-wall carbon nanotubes, nanocarbon black without and with nano-TiO2 and citric acid as a cross-linking agent through exhaustion method and post-curing. Electrical conductivity, methylene blue degradation, UV protection, and thermal stability of the treated fabrics were investigated. The loading of various carbon nanostructures and nano-TiO2 on the polyester fabric confirmed with SEM images and energy-dispersive X-ray spectroscopy. Further, X-ray diffraction, remaining ash percentage via furnace and thermogravimetric analysis, proved the presence of nano-TiO2 on the polyester fabric. The UV protection verified with UV–Vis reflection spectra indicated the highest protection on the nanocarbon black/nano-TiO2/CA-treated fabric. The highest discoloration of methylene blue solution and electrical conductivity obtained on the treated fabric with functional single-wall carbonnano tube/nano-TiO2/citric acid and functional nanocarbon black/nano-TiO2/citric acid. This is related to enhance photocatalytic activities of nano-TiO2 with cooperation of single-wall carbon nanotubes and more surface coating of nanocarbon black on the polyester fabric.

Voltammetric and flow-injection determination of carbohydrates using composite electrodes based on carbon nanotubes and Nickel(II) hexacyanoferrate

The catalytic activities of oxo and hydroxo forms of nickel(II) on the surface of a nickel deposit and an inorganic film of nickel(II) hexacyanoferrate(III) (NiHCF) electrodeposited on a glassy-carbon electrode both unmodified and modified by multi-wall or single-wall (also functionalized) carbon nanotubes in the electrooxidation of glucose, sucrose, and maltose are compared. A more pronounced catalytic effect was obtained in the electrooxidation of these carbohydrates on an electrode modified with functionalized singlewall carbon nanotubes and a NiHCF film. Methods are proposed for the voltammetric and flow-injection determination of carbohydrates on this composite electrode. A linear dependence of the analytical signal on the analyte concentration was observed in the range from 5 × 10−7 to 5 × 10−2 M under stationary conditions and from 0.003 to 0.3 μmol under flow conditions.

A Monte Carlo Simulation of the Adsorption of CO 2 and SO 2 Gases in Pure and Functionalized Single Walled Carbon Nanotubes

Grand canonical Monte Carlo (GCMC) simulation is used to model adsorption of CO 2 and SO 2 molecules by the pure and functionalized single walled carbon nanotubes (SWCNT and FSWCNT). Simulations are conducted for two cases: i) without and ii) with a 5.75 Å clearance between the CNT wall and the walls of the simulation box. Results show that the adsorption capacity for the SO 2 molecules is generally higher than that of the CO 2 molecules, especially at low pressures. Although for both molecules, the inside adsorption is higher at low pressures, the outside adsorption becomes larger above 10 and 2 bar for CO 2 and SO 2 , respectively. At 5 bar, the total amounts of adsorption for case (ii) is higher by ∼ 42% and ∼ 271% for CO 2 and SO 2 , respectively, compared with those for case (i) . Functionalization does not show significant effect on the adsorption of the CO 2 and SO 2 gases. Adsorption of CO 2 and SO 2 gases in the FSWCNT are rather more sensitive to the parameters of the force field, especially those used for the functionalized carbon atoms, than the number of carbon atoms affected by functional groups. The effects of non-spherical interactions on the adsorption isotherms have also been examined.

Competitive detection of pregnancy-associated plasma protein-A in serum using functional single walled carbon nanotubes/chitosan-based electrochemical immunosensor

In this research, a novel electrochemical immunosensor for competitive detection of pregnancy-associated plasma protein-A (PAPP-A) in serum had been successfully developed. The PAPP-A was covalently immobilized on the glass carbon electrode (GCE) modified with functional single walled carbon nanotubes/chitosan (SWNTs/CS) to amplify signal. After the modified GCE was incubated with the intermixture of biotin-anti-PAPP-A antibody and samples PAPP-A, the active streptavidin-alkaline phosphatase (ST-AP) bonded with the remaining biotin-anti-PAPP-A to catalyze the hydrolysis of the enzyme substrate α-NP, then the hydrolysis product could be oxidized to produce the differential pulse voltammetric (DPV) signal. The DPV current decreased with the increasing PAPP-A concentration. Meanwhile, the functionalization of the immunosensor was characterized with three electrochemical techniques: scanning electron microscope (SEM), electrochemical impedance spectroscopic (EIS) and cyclic voltammetric (CV). Under optimal conditions, a good linear relationship between the concentrations of the PAPP-A and DPV currents was achieved in the range from 0.05 to 10μgmL−1 with the detection limit of 39ngmL−1, the reproducibility was calculated to be 3.39% and 8.60% respectively, and a good selectivity was obtained for the developed immunosensors. Finally, this method was successfully applied for direct quantitative detection of complex clinical serum specimens and the results were in good agreement with the time-resolved immunofluorometric assay (TrIFMA) , which makes it be a promising alternative for the clinical detection of PAPP-A in the future.

&lt;I&gt;In Silico&lt;/I&gt; Designed, Self-Assembled, Functionalized Single-Walled Carbon Nanotubes and, Deoxyribose Nucleic Acids (&lt;I&gt;f&lt;/I&gt;-SW-CNT-DNA) Bioconjugate as Probable Biomolecular Transporters

&lt;I&gt;In Silico&lt;/I&gt; Designed, Self-Assembled, Functionalized Single-Walled Carbon Nanotubes and, Deoxyribose Nucleic Acids (&lt;I&gt;f&lt;/I&gt;-SW-CNT-DNA) Bioconjugate as Probable Biomolecular Transporters

Functional Single-Walled Carbon Nanotube-based Molecular Devices

Functional Single-Walled Carbon Nanotube-based Molecular Devices

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Surface‐Assisted Laser Desorption/Ionization Mass Spectrometric Detection of Biomolecules by Using Functional Single‐Walled Carbon Nanohorns as the Matrix

A surface-assisted laser desorption/ionization time-of-flight mass spectrometric (SALDI-TOF MS) method was developed for the analysis of small biomolecules by using functional single-walled carbon nanohorns (SWNHs) as matrix. The functional SWNHs could transfer energy to the analyte under laser irradiation for accelerating its desorption and ionization, which led to low matrix effect, avoided fragmentation of the analyte, and provided high salt tolerance. Biomolecules including amino acids, peptides, and fatty acids could successfully be analyzed with about 3- and 5-fold higher signals than those obtained using conventional matrix. By integrating the advantages of SWNHs and the recognition ability of aptamers, a selective approach was proposed for simultaneous capture, enrichment, ionization, and MS detection of adenosine triphosphate (ATP). This method showed a greatly improved detection limit (1.0 μM) for the analysis of ATP in complex biological samples. This newly designed protocol not only opened a new application of SWNHs, but also offered a new technique for selective MS analysis of biomolecules based on aptamer recognition systems.