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Xueling Ren, Jing Lin, Xuefang Wang, Xiao Liu, Erjuan Meng, Rui Zhang, Yanxiao Sang, Zhenzhong Zhang
The efficacy of RNA interference (RNAi)-based cancer gene therapy is limited by its unexpected side effects, thus necessitating a strategy to precisely trigger conditional gene knockdown. In this study, we engineered a novel photoactivatable RNAi system, named as polyetherimide-modified single-wall carbon nanotube (PEI-SWNT)/pHSP-shT, that enables optogenetic control of targeted gene suppression in tumor cells. PEI-SWNT/pHSP-shT comprises a stimulus-responsive nanocarrier (PEI-SWNT), and an Hsp70B'-promoter-driven RNAi vector (pHSP-shT)...
2017: International Journal of Nanomedicine
Mohammad Towshif Rabbani, Christoph F Schmidt, Alexandra Ros
Single-walled carbon nanotubes (SWNTs) offer unique electrical and optical properties. Common synthesis processes yield SWNTs with large length polydispersity (several tens of nanometers up to centimeters) and heterogeneous electrical and optical properties. Applications often require suitable selection and purification. Dielectrophoresis is one manipulation method for separating SWNTs based on dielectric properties and geometry. Here, we present a study of surfactant and ssDNA wrapped SWNTs suspended in aqueous solutions manipulated by insulator-based dielectrophoresis (iDEP)...
November 13, 2017: Analytical Chemistry
Xiaokai Li, Marina Mariano, Lyndsey McMillon-Brown, Jing-Shun Huang, Matthew Y Sfeir, Mark A Reed, Yeonwoong Jung, André D Taylor
Mechanical fragility and insufficient light absorption are two major challenges for thin flexible crystalline Si-based solar cells. Flexible hybrid single-walled carbon nanotube (SWNT)/Si solar cells are demonstrated by applying scalable room-temperature processes for the fabrication of solar-cell components (e.g., preparation of SWNT thin films and SWNT/Si p-n junctions). The flexible SWNT/Si solar cells present an intrinsic efficiency ≈7.5% without any additional light-trapping structures. By using these solar cells as model systems, the charge transport mechanisms at the SWNT/Si interface are investigated using femtosecond transient absorption...
November 10, 2017: Small
Keigo Otsuka, Taiki Inoue, Etsuo Maeda, Reo Kometani, Shohei Chiashi, Shigeo Maruyama
Ballistic transport and sub-10 nm channel lengths have been achieved in transistors containing one single-walled carbon nanotube (SWNT). To fill the gap between single-tube transistors and high-performance logic circuits for the replacement of silicon, large-area, high-density, and purely semiconducting (s-) SWNT arrays are highly desired. Here we demonstrate the fabrication of multiple transistors along a purely semiconducting SWNT array via an on-chip purification method. Water- and polymer-assisted burning from site-controlled nanogaps is developed for the reliable full-length removal of metallic SWNTs with the damage to s-SWNTs minimized even in high-density arrays...
November 13, 2017: ACS Nano
Yu Ishibashi, Masahiro Ito, Yoshikazu Homma, Kazuo Umemura
We measured the optical responses of single-walled carbon nanotubes (SWNTs) after adding Japanese green tea or catechin. SWNTs were covered with DNA in aqueous solution, and tea or catechin solution was added to the DNA-SWNT suspension. The antioxidant effects of tea and catechin were detected as changes in the near-infrared (NIR) absorption (ABS) and NIR-photoluminescence (PL) spectra of the SWNTs. Commercial Japanese tea, diluted 100 times and containing 15μg/mL catechin, was sufficient for recovering NIR-ABS and NIR-PL spectra when the DNA-SWNT suspension was pre-treated with 0...
October 18, 2017: Colloids and Surfaces. B, Biointerfaces
Satoshi Yasuda, Takahiro Yoshii, Shohei Chiashi, Shigeo Maruyama, Kei Murakoshi
Local surface plasmon resonance (LSPR)-induced oxidation of semiconducting and metallic single-walled nanotubes (SWNTs) on the nanometer scale was investigated using surface-enhanced Raman scattering (SERS) measurements. An isolated SWNT was supported on a well-defined Au nanodimer structure that possesses an LSPR field at the nanogap under light irradiation, and highly intense SERS spectra of the SWNT at the gap region were measured. SERS analysis under O2-saturated solutions and the addition of reactive oxygen species inhibitors demonstrated that condensed singlet oxygen ((1)O2), which is one of the reactive oxygen species, was efficiently generated from a semiconducting SWNT at the nanogap by the LSPR field and led to the local oxidation of the tube...
November 8, 2017: ACS Applied Materials & Interfaces
Zhaoyao Zhan, Rongzhou Lin, Van-Thai Tran, Jianing An, Yuefan Wei, Hejun Du, Tuan Tran, Wenqiang Lu
A wearable and flexible pressure sensor is essential to the realization of personalized medicine through continuously monitoring an individual's state of health and also the development of a highly intelligent robot. A flexible, wearable pressure sensor is fabricated based on novel single-wall carbon nanotube /tissue paper through a low-cost and scalable approach. The flexible, wearable sensor showed superior performance with concurrence of several merits, including high sensitivity for a broad pressure range and an ultralow energy consumption level of 10(-6) W...
October 20, 2017: ACS Applied Materials & Interfaces
Yuichiro Kunai, Albert Tianxiang Liu, Anton L Cottrill, Volodymyr B Koman, Pingwei Liu, Daichi Kozawa, Xun Gong, Michael S Strano
The concept of electrical energy generation based on asymmetric chemical doping of single-walled carbon nanotube (SWNT) papers is presented. We explore 27 small, organic, electron-acceptor molecules that are shown to tune the output open-circuit voltage (VOC) across three types of pristine SWNT papers with varying (n,m) chirality distributions. A considerable enhancement in the observed VOC, from 80 to 440 mV, is observed for SWNT/molecule acceptor pairs that have molecular volume below 120 Å(3) and lowest unoccupied molecular orbital (LUMO) energies centered around -0...
October 20, 2017: Journal of the American Chemical Society
Juan Yang, Daqi Zhang, Yuecong Hu, Chenmaya Xia, Sida Sun, Yan Li
The chirality (n,m) determines all structures and properties of a single-walled carbon nanotube (SWNT), therefore, accurate and convenient (n,m) assignments are vital in nanotube-related science and technology. Previously, a so-called Kataura plot that protracts the excitonic transition energies (Eii's) of SWNTs with various (n,m) with respect to the tube diameter (dt) has been widely utilized by researchers in the nanotube community for all (n,m)-related studies. However, the facts that both Eii and the calculated dt are subject to interactions with the environments make it inconvenient to accurately determine the (n,m) under complex environments...
October 24, 2017: ACS Nano
Fajun Xiao, Can Liu, Kaihui Liu, Wuyun Shang, Weiren Zhu, Jianlin Zhao
We propose and demonstrate an approach for tailoring the Raman response of an individual single-walled carbon nanotube (SWNT) by employing the optical vortex as the excitation. Specifically, we observe the blueshifts of radial breathing mode and G mode when the topological charge of the vortex beam is increased from 0 to 5. Further theoretical analysis yields that the optical absorption and the corresponding laser heating effect of SWNT are inversely proportional to the topological charge of the optical vortex...
July 1, 2017: Optics Letters
David R Barbero, Nicolas Boulanger
Self-assembled percolated networks play an important role in many advanced electronic materials and devices. In nanocarbon composites, decreasing the percolation threshold ϕc is of paramount importance to reduce nanotube bundling, minimize material resources and costs, and enhance charge transport. Here we demonstrate that three-dimensional nanoconfinement in single-wall carbon nanotube/polymer nanocomposites produces a strong reduction in ϕc, reaching the lowest value ever reported in this system of ϕc ≈ 1...
October 24, 2017: ACS Nano
Guanghui Li, Mohammad Suja, Mingguang Chen, Elena Bekyarova, Robert C Haddon, Jianlin Liu, Mikhail E Itkis
Ultraviolet (UV) photodetectors based on heterojunctions of conventional (Ge, Si, and GaAs) and wide bandgap semiconductors have been recently demonstrated, but achieving high UV sensitivity and visible-blind photodetection still remains a challenge. Here, we utilized a semitransparent film of p-type semiconducting single-walled carbon nanotubes (SC-SWNTs) with an energy gap of 0.68 ± 0.07 eV in combination with a molecular beam epitaxy grown n-ZnO layer to build a vertical p-SC-SWNT/n-ZnO heterojunction-based UV photodetector...
October 5, 2017: ACS Applied Materials & Interfaces
C T Stoppiello, J Biskupek, Z Y Li, G A Rance, A Botos, R M Fogarty, R A Bourne, J Yuan, K R J Lovelock, P Thompson, M W Fay, U Kaiser, T W Chamberlain, A N Khlobystov
The preparation of inorganic nanomaterials with a desired structure and specific properties requires the ability to strictly control their size, shape and composition. A series of chemical reactions with platinum compounds carried out within the 1.5 nm wide channel of single-walled carbon nanotubes (SWNTs) have demonstrated the ability of SWNTs to act as both a very effective reaction vessel and a template for the formation of nanocrystals of platinum di-iodide and platinum di-sulphide, materials that are difficult to synthesise in the form of nanoparticles by traditional synthetic methods...
October 5, 2017: Nanoscale
Md Ashraful Islam, Jung Han Kim, Anthony Schropp, Hirokjyoti Kalita, Nitin Choudhary, Dylan Weitzman, Saiful I Khondaker, Kyu Hwan Oh, Tania Roy, Hee-Suk Chung, Yeonwoong Jung
Two-dimensional (2D) transition metal dichalcogenides (TMDs) such as molybdenum or tungsten disulfides (MoS2 or WS2) exhibit extremely large in-plane strain limits and unusual optical/electrical properties, offering unprecedented opportunities for flexible electronics/optoelectronics in new form factors. In order for them to be technologically viable building-blocks for such emerging technologies, it is critically demanded to grow/integrate them onto flexible or arbitrary-shaped substrates on a large wafer-scale compatible with the prevailing microelectronics processes...
October 11, 2017: Nano Letters
Kazuo Umemura, Shizuma Sato, Gilbert Bustamante, Jing Yong Ye
Surface modification of single-walled carbon nanotubes (SWNTs) with DNA molecules has attracted much attention in recent years to increase SWNT solubility and make various SWNT-based nanobiodevices. Therefore, there is a critical need to quantify the interaction between DNA molecules and SWNT surfaces, particularly the intermediate structures during DNA adsorption. In this study, we demonstrate the ability to detect the adsorption of DNA oligomers on SWNT surfaces by fluorescence spectroscopy. Fluorescein-labelled, 30mer, thymine oligonucleotides (F-T30) were employed as a fluorescent probe to study the interaction of DNA with SWNTs...
September 12, 2017: Colloids and Surfaces. B, Biointerfaces
Jinsook Sim, Somin Kim, Myungsu Jang, Minsuk Park, Hyunkyu Oh, Sang-Yong Ju
Symmetry breaking of single-walled carbon nanotubes (SWNTs) has profound effects on their optoelectronic properties that are essential for fundamental study and applications. Here, we show that isomeric SWNTs that exhibit identical photoluminescence (PL) undergo symmetry breaking by flavin mononucleotide (FMN) and exhibit dual PLs and different binding affinities (Ka). Increasing the FMN concentration leads to systematic PL shifts of SWNTs according to structural modality and handedness due to symmetry breaking...
October 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Benjamin J Bucior, German V Kolmakov, JoAnna M Male, Jinchen Liu, De-Li Chen, Prashant Kumar, J Karl Johnson
Single-walled carbon nanotubes (SWNTs) have been shown from both simulations and experiments to have remarkably low resistance to gas and liquid transport. This has been attributed to the remarkably smooth interior surface of pristine SWNTs. However, real SWNTs are known to have various defects that depend on the synthesis method and procedure used to activate the SWNTs. In this paper, we study adsorption and transport properties of atomic and molecular fluids in SWNTs having vacancy point defects. We construct models of defective nanotubes that have either unrelaxed defects, where the overall structure of the SWNT is not changed, or reconstructed defects, where the bonding topology and therefore the shape of the SWNT is allowed to change...
September 27, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Debabrata Pramanik, Prabal K Maiti
Separation and sorting of pristine carbon nanotubes (CNTs) from bundle geometry is a very challenging task due to the insoluble and nondispersive nature of CNTs in aqueous medium. Recently, many studies have been performed to address this problem using various organic and inorganic solutions, surfactant molecules, and biomolecules as dispersing agents. Recent experimental studies have reported the DNA to be highly efficient in dispersing CNTs from bundle geometry. However, there is no microscopic study and also quantitative estimation of the dispersion efficiency of the DNA...
October 11, 2017: ACS Applied Materials & Interfaces
Fahimeh Charbgoo, Mehrdad Behmanesh, Maryam Nikkhah
Advances in nanobiotechnology and targeting strategy could improve the delivery of therapeutic molecules into cancer cells, leading to improved treatment efficiency with minimal side effects on normal cells. To design an efficient nanocarrier, consideration of parameters that facilitate direct drug delivery into the target cells is important. We studied the effect of single wall carbon nanotubes size on their cell internalization level via the folate receptor-mediated pathway through folic acid targeting. Folate-SWNTs were covalently synthesized and characterized...
August 30, 2017: Biotechnology and Applied Biochemistry
Jian Zhang, Siyu Liu, Jean Pierre Nshimiyimana, Ya Deng, Gu Hou, Xiannian Chi, Xiao Hu, Zongzhi Zhang, Pei Wu, Gongtang Wang, Weiguo Chu, Lianfeng Sun
Suspended single-walled carbon nanotubes (SWNTs) have advantages in mechanical resonators and highly sensitive sensors. Large-scale fabrication of suspended SWNTs array devices and uniformity among SWNTs devices remain a great challenge. This study demonstrates an effective, fast, and wafer-scale technique to fabricate suspended SWNT arrays, which is based on a dynamic motion of silver liquid to suspend and align the SWNTs between the prefabricated palladium electrodes in high temperature annealing treatment...
August 21, 2017: Small
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