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Jianing An, Zhaoyao Zhan, Gengzhi Sun, Hari Krishna Salila Vijayalal Mohan, Jinyuan Zhou, Young-Jin Kim, Lianxi Zheng
Leveraging the unique properties of single-walled carbon nanotube (SWNT) intramolecular junctions (IMJs) in innovative nanodevices and next-generation nanoelectronics requires controllable, repeatable, and large-scale preparation, together with rapid identification and comprehensive characterization of such structures. Here we demonstrate SWNT IMJs through directly growing ultralong SWNTs on trenched substrates. It is found that the trench configurations introduce axial strain in partially suspended nanotubes, and promote bending deformation in the vicinity of the trench edges...
December 1, 2016: Scientific Reports
Pan Li, Jin Zhang
The synthesis of SWNTs has achieved great success with the development of synthetic methodologies. From the viewpoint of exploiting the exceptional electrical properties of single-walled carbon nanotubes (SWNTs) in advanced applications, one of the most difficult challenges is how to assemble the SWNTs with high degrees of alignment and purity in electronic conducting (mainly semiconducting) behavior into functional nanodevices. Numerous approaches have been developed to reach this goal, which could be divided into two categories...
December 2016: Topics in Current Chemistry (Journal)
Bing Zhang, Jia Xu, Shu-Fan Mo, Jian-Xi Yao, Song-Yuan Dai
Electron transfer between cytochrome c (Cytc) and electrodes can be influenced greatly by the orientation of protein on the surface of the electrodes. In the present study, different initial orientations of Cytc on the surface of five types of single-walled carbon nanotubes (SWNTs), with different diameters and chirality, were constructed. Properties of the orientations of proteins on the surface of these tubes were first investigated through molecular dynamics simulations. It was shown that variations in SWNT diameter do not significantly affect the orientation; however, the chirality of the SWNTs is crucial to the orientation of the heme embedded in Cytc, and the orientation of the protein can consequently be influenced by the heme orientation...
December 2016: Journal of Molecular Modeling
Satoshi Yasuda, Shinji Hoshina, Shohei Chiashi, Shigeo Maruyama, Kei Murakoshi
We present an electronic structural analysis of an individual single-walled carbon nanotube (SWNT) by employing electrochemical surface-enhanced Raman scattering (SERS). An isolated SWNT was supported on a well-defined Au nanodimer structure, which possesses a localized surface plasmon resonance (LSPR) field at the nanogap, and highly intense SERS spectra were obtained for the SWNT at the gap region. The absolute potential of the Fermi level of the isolated SWNT in an ionic liquid was determined from the electrochemical potential dependence of the SERS intensity showing the dependence on the chirality of SWNTs...
December 7, 2016: Nanoscale
Nikita V Kurnosov, Victor S Leontiev, Victor A Karachevtsev
The influence of tip sonication duration on the spectral characteristics of carbon single-walled nanotubes (SWNTs) in aqueous suspension with single-stranded DNA (ssDNA) has been studied by NIR luminescence, NIR absorption, and Raman spectroscopy. It was revealed that prolongation of sonication leads to weakening of the SWNT polymer coverage and appearance of additional defects on the nanotube surface. Prolongation of the tip sonication treatment of SWNT/ssDNA from 30 to 90 min leads to the increase of the number of individual nanotubes in the aqueous suspension, but it significantly decreases the photoluminescence (PL) from semiconducting SWNTs because more defects are formed on the nanotube surface...
December 2016: Nanoscale Research Letters
Hareem Maune, Si-Ping Han
Single-walled carbon nanotubes (SWNT or CNT) have unique and well-known high-performance material properties that can enable revolutionary increases in the performance of electronic devices and architectures. However, fabrication of large-scale SWNT-based ICs is an enormously challenging, unsolved problem, and self-assembly is likely needed for critical steps. Over the past several years, methods have been introduced to created ordered carbon nanotube structures using DNA guided self-assembly. In this chapter, we briefly review the challenges involved in using DNA to assemble SWNT nanostructures, and then give detailed methods to assemble dense, aligned SWNT arrays...
2017: Methods in Molecular Biology
Yutaka Maeda, Yuya Takehana, Jing-Shuang Dang, Mitsuaki Suzuki, Michio Yamada, Shigeru Nagase
Alkylated single-walled carbon nanotubes (SWNTs) have been thermally treated to determine the influence of substituents and the degree of functionalization on their thermal stability and photoluminescence (PL) properties. Alkylated SWNTs were prepared by treating SWNTs with sodium naphthalenide and alkyl bromide. The defunctionalization of the alkylated SWNTs was monitored by absorption and Raman spectra. Selective recovery of the characteristic absorption and radial breathing mode peaks was observed during the thermal treatment, which indicates that the thermal stability of the alkylated SWNTs decreases with increases in SWNT diameter and degree of functionalization...
October 24, 2016: Chemistry: a European Journal
George F Reiter, Aniruddha Deb, Yoshiharu Sakurai, Masayoshi Itou, Alexander I Kolesnikov
X-ray Compton scattering measurements of the electron momentum distribution in water confined in both single walled and double walled carbon nanotubes (SWNT and DWNT), as a function of temperature and confinement size, presented here, together with earlier measurements of the proton momentum distribution in the same systems, using neutron Compton scattering, provide a coherent picture of an anomalous state of water that exists because of nano-confinement. This state cannot be described by the weakly interacting molecule picture...
October 17, 2016: Journal of Physical Chemistry Letters
Griet Depotter, Jean-Hubert Olivier, Mary G Glesner, Pravas Deria, Yusong Bai, George Bullard, Amar S Kumbhar, Michael J Therien, Koen Clays
We report the first-order hyperpolarizabilities (βHRS values) of individualized, length-sorted (700 ± 50 nm long) (6,5) SWNTs and corresponding polymer-wrapped (6,5) SWNT superstructures. These SWNT-based nanohybrids feature semiconducting polymers that wrap the SWNT surface in an exclusive left-handed helical fashion. Manipulation of the polymer electronic structures in these well-defined nanoscale objects provides a new avenue to modulate the magnitude of βHRS at long wavelength (1280 nm).
October 6, 2016: Chemical Communications: Chem Comm
Yoko Matsuzawa, Yuko Takada, Hirokuni Jintoku, Hideyuki Kihara, Masaru Yoshida
We describe the application of photodetachable and recyclable dispersants for SWNTs in the fabrication of photo-patterned SWNT thin films. Because the adsorption and desorption of the dispersants on the SWNT surfaces affect not only their dispersibility in water but also their solubility, SWNT photo-patterns were obtained on glass substrates in only three steps, i.e. casting the SWNT/dispersants solution, UV-light exposure of the casted SWNT/dispersants films through a photomask, and subsequent rinsing with neutral water...
October 10, 2016: ACS Applied Materials & Interfaces
Yutaka Maeda, Shun Minami, Yuya Takehana, Jing-Shuang Dang, Shun Aota, Kazunari Matsuda, Yuhei Miyauchi, Michio Yamada, Mitsuaki Suzuki, Rui-Sheng Zhao, Xiang Zhao, Shigeru Nagase
Single-walled carbon nanotubes (SWNTs) were subjected to alkylation using alkyl bromide and alkyl dibromide, and the photoluminescence (PL) properties of the resulting alkylated SWNTs were characterized. Two new PL peaks were observed along with the intrinsic PL peak at 976 nm when alkyl bromide was used (SWNT-Bu: ∼1095 and 1230 nm, SWNT-Bn: 1104 and 1197 nm). In contrast, the use of α,α'-dibromo-o-xylene as an alkyl dibromide primarily resulted in only one new PL peak, which was observed at 1231 nm. The results revealed that the Stokes shift of the new peaks was strongly influenced by the addition patterns of the substituents...
September 29, 2016: Nanoscale
Keigo Otsuka, Taiki Inoue, Yuki Shimomura, Shohei Chiashi, Shigeo Maruyama
We observe field emission between nanogaps and voltage-driven gap extension of single-walled carbon nanotubes (SWNTs) on substrates during the electrical breakdown process. Experimental results show that the gap size is dependent on the applied voltage and humidity, which indicates high controllability of the gap size by appropriate adjustment of these parameters in accordance with the application. We propose a mechanism for the gap formation during electrical breakdown as follows. After small gaps are formed by Joule heating-induced oxidation, SWNTs on the anode side are electrochemically etched due to physically-adsorbed water from the air and the enhanced electric field at the SWNT tips...
September 15, 2016: Nanoscale
Xiaoyuan Liang, Wenting Shang, Chongwei Chi, Chaoting Zeng, Kun Wang, Chihua Fang, Qingshan Chen, Huiyu Liu, Yingfang Fan, Jie Tian
Recently, photothermal therapy (PTT) has become viewed as an ideal auxiliary therapeutic treatment for cancers. However, the development of safe, convenient, and highly effective photothermal agents remains a great challenge. In this study, we prepared single-walled carbon nanotubes (SWNTs) for PTT against breast tumors under the guidance of infrared fluorescent cyanines. Tumors were accurately located using near-infrared imaging (NIR) and then exposed to laser irradiation. Both the in vivo and in vitro results showed that the SWNTs have high stability and low cytotoxicity...
September 30, 2016: Cancer Letters
Chompoonut Rungnim, Thanyada Rungrotmongkol, Rungtiva P Poo-Arporn
In the present study, we describe here the pH condition activating doxorubicin (DOX) anticancer drugs loading and release over single-wall carbon nanotube (SWNT) non-covalently wrapped with chitosan (CS). The possibility of drug displacement on DOX/CS/SWNT nanocarrier was investigated using molecular dynamics simulations. The drug loading and release were monitored via displacement analysis and binding energy calculations. The simulated results clearly showed that the drugs well interacted with the CS/SWNT at physiological pH (pH 7...
September 21, 2016: Journal of Molecular Graphics & Modelling
David R Barbero, Samuel D Stranks
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...
September 16, 2016: Advanced Materials
Vasanth S Murali, Ruhung Wang, Carole A Mikoryak, Paul Pantano, Rockford K Draper
Single-walled carbon nanotubes (SWNTs) are used in the near infrared (NIR)-mediated thermal ablation of tumor cells because they efficiently convert absorbed NIR light into heat. Despite the therapeutic potential of SWNTs, there have been no published studies that directly quantify how many SWNTs need be associated with a cell to achieve a desired efficiency of killing, or what is the most efficient subcellular location of SWNTs for killing cells. Herein we measured dose response curves for the efficiency of killing correlated to the measured amounts of folate-targeted SWNTs that were either on the surface or within the vacuolar compartment of normal rat kidney cells...
October 21, 2016: Nanotechnology
Qi Wang, Chunya Wang, Mingchao Zhang, Muqiang Jian, Yingying Zhang
Silkworm silk is gaining significant attention from both the textile industry and research society because of its outstanding mechanical properties and lustrous appearance. The possibility of creating tougher silks attracts particular research interest. Carbon nanotubes and graphene are widely studied for their use as reinforcement. In this work, we report mechanically enhanced silk directly collected by feeding Bombyx mori larval silkworms with single-walled carbon nanotubes (SWNTs) and graphene. We found that parts of the fed carbon nanomaterials were incorporated into the as-spun silk fibers, whereas the others went into the excrement of silkworms...
October 12, 2016: Nano Letters
Myungsu Jang, Somin Kim, Haneul Jeong, Sang-Yong Ju
Sorted single-walled carbon nanotubes (SWNTs) are of paramount importance for their utilization in high-end optoelectronic applications. Sodium cholate (SC)-based density gradient ultracentrifugation (DGU) has been instrumental in isolating small diameter (d t) SWNTs. Here, we show that SWNTs wrapped by flavin mononucleotide (FMN) as a dispersing agent are sorted in DGU, and show sorting order reversal behavior, departing from prototypical SC-SWNT trends. Larger d t SWNTs are sorted in lower density (ρ), and buoyant ρ distribution of FMN-SWNT ranges from 1...
October 14, 2016: Nanotechnology
Felix F Bergler, Sabine Stahl, Annika Goy, Friedrich Schöppler, Tobias Hertel
The interaction of sodium cholate (NaC) with (6,5) single-wall carbon nanotubes (SWNTs) is investigated using photoluminescence spectroscopy. Dilution of SWNT-NaC suspensions is accompanied by changes in the exciton PL quantum yield and peak emission energy. An abrupt change of the exciton emission peak energy at NaC concentrations between 10 and 14 mM indicates strongly cooperative formation of a micellar phase on (6,5) SWNT surfaces with a Hill coefficient of nH = 65 ± 6. This is in contrast to the formation of free NaC micelles with aggregation numbers of only about 4 and suggests that the cooperativity of NaC micelle formation on nanotube surfaces is strongly substrate-enhanced...
September 20, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
He Zhao, Yu Chao, Jingjing Liu, Jie Huang, Jian Pan, Wanliang Guo, Jizhi Wu, Mao Sheng, Kai Yang, Jian Wang, Zhuang Liu
Single-walled carbon nanotubes (SWNTs) with various unique properties have attracted great attention in cancer theranostics. Herein, SWNTs are coated with a shell of polydopamine (PDA), which is further modified by polyethylene glycol (PEG). The PDA shell in the obtained SWNT@PDA-PEG could chelate Mn(2+), which together with metallic nanoparticulate impurities anchored on SWNTs offer enhanced both T1 and T2 contrasts under magnetic resonance (MR) imaging. Meanwhile, also utilizing the PDA shell, radionuclide (131)I could be easily labeled onto SWNT@PDA-PEG, enabling nuclear imaging and radioisotope cancer therapy...
2016: Theranostics
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