bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tuning Single-Walled Carbon Nanotube (SWCNT) Membrane Interactions
Authors: Antonucci Alessandra , Schuergers Nils , Boghossian Ardemis Anoush 
Published: February 2020

The remarkable physicochemical properties of carbon nanomaterials make them promising candidates for biomedical and biotechnological applications. In particular, the distinctive optical and structural characteristics of single-walled carbon nanotubes (SWCNTs) have inspired the development of biologically applicable optical sensors and molecular delivery scaffolds1,2. Several studies have largely focused on enabling cell uptake of SWCNTs by engineering the SWCNT surface through non-covalent side-wall functionalizations. Non-covalent functionalization with a rich variety of biomolecules and polymers has been shown to potentially increase SWCNTs solubility and membrane translocation while endowing these nanostructures with enhanced biocompatibility3. These functionalizations have been engineered to permit SWCNT uptake by a variety of mammalian cells through both passive and energy-dependent pathways. Most recently, this platform was applied to intact chloroplasts to augment their photosynthetic capability in novel nanobionic devices4. Although factors such as cell type, functionalization zeta-potential, particle size, and membrane composition have been shown to affect uptake, these findings have largely relied on empirical approaches towards engineering uptake mechanisms5,6.
Our work builds on these empirical findings to establish engineering design rules for enabling SWCNT-membrane interactions. We performed a systematic investigation of the effect of SWCNT functionalization on membrane penetration properties using a novel biological host. The results of this study were used to not only elucidate the underlying interaction on a molecular level, but also develop the first of a new generation of light-harvesting nanobionic devices.
References:
1. Boghossian, A. a. et al. Near-infrared fluorescent sensors based on single-walled carbon nanotubes for life sciences applications. ChemSusChem
4, 848–863 (2011).
2. Oliveira, S. F. et al. Protein Functionalized Carbon Nanomaterials for Biomedical Applications. Carbon N. Y. (2015).
3. Vardharajula, S. et al. Functionalized carbon nanotubes: biomedical applications. Int. J. Nanomedicine
7, 5361–74 (2012).
4. Giraldo, J. P. et al. Plant nanobionics approach to augment photosynthesis and biochemical sensing. Nat. Mater.
13, 400–8 (2014).
5. Kostarelos, K. et al. Cellular uptake of functionalized carbon nanotubes is independent of functional group and cell type. Nat. Nanotechnol.
2, 108–113 (2007).
6. Holt, B. D., Dahl, K. N., Islam, M. F. & Al, H. E. T. Cells Take up and Recover from Nanotubes with Two Distinct Rates. 3481–3490 (2012)
Precious-Metal-Free Carbon Nano Fiber with N-Doped Graphene Nanoplatelets As Electrocatalyst for Oxygen Reduction Reaction
Authors: Yoo Seonyoung , Shin Jeeyoung , Kim Guntae 
Published: February 2020

The development of highly active and stable catalysts for the oxygen reduction reaction (ORR) is an important task in the practical application of metal-air batteries and fuel cells. Carbon nanomaterials doped with heteroatoms, such as N and S, are attractive materials for use as electrocatalysts toward the ORR due to their low cost, high efficiency and high durability. Herein we report carbon nanofiber (CNF) incorporated Fe-N-doped graphene nano platelets (Fe@NGnP) prepared as a catalyst via a novel and simple synthesis approach. The activated CNF-Fe@NGnP catalysts exhibit substantially improved activity for oxygen reduction compared to that of currently used carbon blacks and Pt/carbon catalysts.
(Invited) In Vivo Carbon Nanotube Sensors
Authors: Iverson Nicole M , Bisker Gili , Farias Edgardo , Ivanov Vsevolod , Ahn Jiyoung , Barone Paul W , Shandell Mia , Trudel Laura J , Sen Selda , Sen Fatih , Atolia Esha , Wogan Gerald N , Strano Michael S 
Published: February 2020

Single-walled carbon nanotubes (SWNT) are particularly attractive for biomedical applications because they exhibit unique optical properties, fluorescing in the near infrared tissue transparency window, and allow for information transfer without the need for an internal power source. Although SWNT have been used as highly-sensitive detectors for various compounds, their use as in vivo biomarkers requires the simultaneous optimization of multiple parameters, including molecular recognition, biocompatibility, high fluorescence quantum efficiency and signal transduction. This work demonstrates two SWNT delivery mechanisms for in vivo detection of an inflammatory factor, nitric oxide (NO), that is associated with numerous diseases, including cancer, but is poorly understood due to its fast degradation rate and the lack of detection devices. First, a polyethylene glycol ligated copolymer is shown to stabilize SWNT sensors in physiological solutions, enabling an intravenous injection into mice. Second, a subcutaneous implant is investigated, with multiple SWNT concentrations, hydrogel shapes and sizes, and the gel’s physical properties examined to determine the preferred material for implantation. We found that both the injected and implanted SWNT are able to detect inflammation within an animal, thus providing the first demonstration of in vivo SWNT sensors as well as the first long term in vivo NO detection modality. This work demonstrates the ability of SWNT sensors to be utilized for in vivo data collection and possibly a wide range of biomedical applications.
Antibacterial Mechanisms of Nano-Graphene Oxide By Measuring Membrane Interactions
Authors: Robb Sarah M. , Li Maxwell , Dahl Kris Noel , Islam Mohammad F. 
Published: February 2020

Bacterial resistance to traditional small molecule antibiotics has led to the need for antimicrobial agents that use an alternative mechanism to kill or inhibit bacterial growth. A promising material for this application is graphene oxide (GO), but the reports of the antibacterial activity have varied. Also, the mechanisms of antibacterial activity are uncertain, but there are three proposed theories: (i) the edges of the 2D sheets lyse and disrupt the bacterial membrane, (ii) the sheets cover the cell and limit access to vital nutrients, and (iii) GO causes metabolic oxidative stress to the cells. In this study, we investigated the effect of GO’s size on its antimicrobial effects by measuring growth of planktonic Escherichia coli (E. coli) with exposure to GO. We have found nanometer-sized GO (nGO) significantly inhibit the growth of E. coli, but micrometer-sized GO (µGO) did not significantly inhibit E. coli growth, showing GO antibacterial efficacy to be dependent on physicochemical properties. In treating human cells in culture with similar concentrations of GO we find that neither µGO nor nGO had toxic or deleterious impacts on cell function. One major difference between bacteria and human cells is membrane composition and mechanics. To investigate the interaction on a molecular level, we exposed lipid membrane vesicles to µGO and nGO. Altered lipid composition and tension allow us to investigate the membrane impacts in a controlled way. Overall, this knowledge will be informative for the design of future biomaterials to prevent bacterial growth and infections with little impact on human cells.
Design and Synthesis of Mwcnts Discrete 3D Microparticles for the Organized Assembly of High Performance Materials
Authors: Maggini Laura , De Volder Michael F. L. 
Published: February 2020

The remarkable mechanical, electrical, thermal and optical properties of carbon nanotubes (CNTs) are only valid for individual particles, and are generally lost when bulk CNT materials are integrated in devices.[1-3] The controlled manufacturing of macroscopic functional and high-performance CNT-materials, retaining the compelling properties of individual tubes, has hence become of paramount importance to allow their full exploitation within commercial products.
Herein we report an unprecedented sequential engineering of the architecture of CNT materials, from the nano-, to the micro- and macroscale level. Specifically, we report on a a microfluidic assisted methodology to generate discrete 3D CNT microparticles, to be employed in large area self-assembly processes, enabling a high degree of hierarchization and tailoring of the CNT material.
Such controlled multiscale engineering, paves the way for the implementation of a property-conservative manufacturing of CNT-based materials, boosting their performance–to–cost ratio, and integration in a vast set of applications with high societal and industrial impact, such as high performance filters, catalysts, and energy storage devices.

Figure 1
Rotaxanes Meet Carbon Nanotubes. Synthesis and Physical Properties of Mechanically Interlocked Derivatives of Carbon Nanotubes
Authors: Perez Emilio M 
Published: February 2020

Extensive research has been devoted to the chemical manipulation of carbon nanotubes. The attachment of molecular fragments through covalent-bond formation produces kinetically stable products, but implies the saturation of some of the C-C double bonds of the nanotubes.[1] Supramolecular modification maintains the structure of the SWNTs but yields labile species.[2] Here, we present a strategy for the synthesis of mechanically interlocked derivatives of SWNTs (MINTs).[3] In the key rotaxane-forming step, we employed macrocycle precursors equipped with two recognition units and terminated with bisalkenes that were closed around the nanotubes through ring-closing metathesis. The mechanically interlocked nature of the derivatives is probed by analytical, spectroscopic, and microscopic techniques, as well as by appropriate control experiments.[4,5] Remarkably, bulk reaction data confirm the interlocked nature of MINTs.[6] Comprehensive photophysical, electrochemical and theoretical characterization experiments indicate that the formation of MINTs goes hand in hand with distinct effects on the physical properties of both the carbon nanotubes and the macrocycles, clearly different from what is found in non-interlocked supramolecular references. The changes affect fundamental properties, such as solubility, diffusion coefficient, and electronic interaction between macrocycles and nanotubes.[7]

[1] Singh, P.; Campidelli, S.; Giordani, S.; Bonifazi, D.; Bianco, A.; Prato, M. Chem. Soc. Rev.
2009, 38, 2214.
[2] Zhao, Y.-L.; Stoddart, J. F. Acc. Chem. Res.
2009, 42, 1161.
[3] de Juan, A.; Pérez, E. M. Nanoscale
2013, 5, 141.
[4] de Juan, A.; Pouillon, Y.; Ruiz-González, L.; Torres-Pardo, A.; Casado, S.; Martín, N.; Rubio, A.; Pérez, E. M. Angew. Chem., Int. Ed.
2014, 53, 5394. (Highlighted in Chem&Eng News, 2014, 92, 31.)
[5] López-Moreno, A.; Pérez, E. M. Chem. Commun., 2015, 51, 5421
[6] de Juan, A.; Bernal, M. M.; Pérez, E. M. ChemPlusChem,
2015, 80, 1153.
[7] Martínez-Periñán, E.; de Juan, A.; Pouillon, Y.; Martín, N.; Schierl, C.; Strauss, V.; Rubio, A.; Guldi, D.; Lorenzo, E.; and Pérez, E. M. submitted

Figure 1
Carbon Nanotube Array Field Effect Transistors with High Current Density and On/Off Ratio
Authors: Brady Gerald J , Way Austin J , Jaccoberger Robert M , Joo Yongho , Gopalan Padma , Arnold Michael S. 
Published: February 2020

Single walled carbon nanotubes (SWCNTs) exhibit extraordinarily high current carrying capacity and suitable band gaps for logic and thin film field-effect transistors (FETs). Progress in honing the exceptional properties of SWCNTs at the multi-tube level, however, has been dampened by incremental advances in the materials science of electronic type sorting and assembly of SWCNTs. To address these challenges we leveraged the exceptional semiconducting sorting fidelity of polyfluorene polymers and we pioneered an alignment technique known as Floating Evaporative Self-Assembly (FESA).1 Recently, we demonstrated individually placed and uniformly pitched purely semiconducting SWCNT arrays using these techniques, allowing for negligible current lost to scaling when the arrays were implemented as the channel in FETs. The SWCNT array FETs exhibited the highest on-state conductance of 261 μS/μm with a simultaneous on/off conductance ratio exceeding 105 for a multi-tube SWCNT FET.2 Here we present our recent optimization of the contact resistance at the palladium-SWCNT interface, which enables a substantial increase in device on-current density compared to our previous report.
For SWCNTs, the quality of the contact-semiconductor interface is highly dependent on the SWCNT packing density, film cleanliness, and surface energy, where any non-idealities may lead to poor palladium film adhesion, or even complete film delamination.3 To address the contact challenge we perform surface treatments on the SWCNT array prior to depositing palladium contacts, which involves rinsing the SWCNT arrays in specific solvents and annealing the films in vacuum. In XPS and optical absorbance spectra, we observe significant mass reduction of the polyfluorene wrapper while maintaining the quality and alignment of the SWCNT array. AFM height maps of the palladium contacts deposited on top of the surface treated SWCNTs demonstrate nearly ideal conformation of the palladium on the SWCNT array. The surface-treated SWCNT array FETs exhibit more than 10-fold improvement in the device on-conductance compared to non-treated samples.
[1] Y. Joo, G. J. Brady, M. S. Arnold, and P. Gopalan, Langmuir 30 (12), 3460 (2014).
[2] G. J. Brady, Y. Joo, M. Y. Wu, M. J. Shea, P. Gopalan, and M. S. Arnold, ACS Nano 8 (11), 11614 (2014).
[3] V. Perebeinos and J. Tersoff, Physical Review Letters 114 (8), 4 (2015).
Stretchable Carbon Nanotube Transistors Enabled By Buckled Carbon Nanotube Thins Films, Ion Gel Gate Dielectrics, and Metal Electrodes
Authors: Wu Meng-Yin , Zhao Juan , Xu Feng , Arnold Michael S. 
Published: February 2020

Deformable field-effect transistors (FETs) are expected to facilitate new technologies like stretchable displays, conformal devices, and electronic skins. Thin film percolating networks of electronic-type controlled semiconducting carbon nanotubes are highly intriguing options for the active channel of stretchable FETs due to the excellent mechanical resilience of individual nanotubes, their possibility to accommodate large strain in thin film form via nanotube–nanotube sliding and buckling, and their exceptional charge transport properties. We demonstrate stretchable FETs based on buckled thin films of polyfluorene-wrapped semiconducting single-walled carbon nanotubes as the channel, buckled metal films as electrodes, and unbuckled flexible ion gel films as the dielectric.[1] The buckled thin film morphology is induced by depositing the nanotubes onto a pre-strained polydimethylsiloxane (PDMS) substrate and then releasing it, greatly improving the device stretchability. The FETs are stretchable up to 50% without appreciable degradation in performance before failure of the ion gel film. We furthermore show that by buckling the ion gel, the integrity and performance of the nanotube FETs are extended to nearly 90% elongation, limited by the stretchability of the elastomer substrate.[2] The FETs maintain an on/off ratio of >104 and a field-effect mobility of 5 cm2 V−1 s−1 under elongation and demonstrate invariant performance over 1000 stretching cycles.

[1] Xu F, Wu M-Y, Safron NS, Singha Roy S, Jacobberger RM, Bindl DJ, Seo J-H, Chang T-H, Ma Z, Arnold MS, Highly Stretchable Carbon Nanotube Transistors with Ion Gel Gate Dielectrics, NANO LETTERS, 4 (2), pp 682–686 (2014).

[2] Wu M-Y, Zhao J, Xu F, Chang T-H, Jacobberger RM, Ma Z, Arnold MS, Highly Stretchable Carbon Nanotube Transistors Enabled by Buckled Ion Gel Gate Dielectrics, APPLIED PHYSICS LETTERS, 107, 053301 (2015).
(Invited) Bulk Synthesis of Oxygen-Doped Single-Walled Carbon Nanotubes and Their Application As Fluorescent Probes
Authors: Okazaki Toshiya 
Published: February 2020

It has been found that the photoluminescence (PL) efficiency of single-walled carbon nanotubes (SWCNTs) can be enhanced by substituting oxygen atoms to the carbon network of the tube wall [1]. The oxygen-doped SWCNTs (o-SWCNTs) have been mostly prepared by the exposure of ozone to the SWCNTs solution under the light. This method can provide only a small amount of o-SWCNTs, and the surfactants are normally adsorbed on the surface of the obtained o-SWCNTs, which prevents further applications of the material. Recently, we found a very simple method for obtaining o-SWCNTs in bulk. In this meeting, the synthesis method and the characterization of the o-SWCNTs, and their application as in-vivo and in-vitro near-infrared imaging probes will be reported.

1. S. Ghosh, S. M. Bachilo, R. A. Simonette, K. M. Beckingham, R. B. Weisman, Science, 330, 1656 (2010).
Photoluminescence from Thin Carbon Nanotube Films
Authors: Namal Imge , Schoeppler Friedrich , Hertel Tobias 
Published: February 2020

Their remarkable light absorption and energy transport characteristics make single-wall carbon nanotubes (SWNTs) intriguing candidates for photovoltaic applications. Here, we study the photophysical properties of polymer wrapped SWNT films with varying thickness, so as to help identify processes which may affect device performance and that may impose limitations on the use of SWNT thin films as active layers in photovoltaic devices.
Non-radiative exciton decay is of particular interest in this context and we have studied its dependence on the thickness of monochiral SWNT films. The films were made of PFOBPy wrapped and highly (6,5) enriched SWNT suspensions using a modified version of the filtration wet transfer technique reported earlier.1 Non radiative decay was probed by means of photoluminescence (PL) spectroscopy and by comparison of thin film data with data obtained from bulk suspensions. For thicker films we observe a pronounced decrease of the PL quantum yield (QY) for emission from the first subband S1 exciton state. However, the total PL QY is much less strongly affected by interactions within the thin film network because of a considerable shift of PL intensity to lower lying states. Surprisingly, some of the lower energy emission resembles PL phonon-sidebands of the first subband exciton which was previously attributed to the coupling between K-point phonons and dark excitons by Murakami et. al.2

Wu, Z.. Science 305, Nr. 5688 (2004): 1273–76.

Murakami, Y., Benjamin L., Said K., Nobutsugu M., Tatsuya O., Shigeo M. Phys. Rev. B 79, Nr. 19 (2009): 195407.
Angular Emission Properties of Single-Wall Carbon Nanotubes and Individual Covalent Dopant Sites
Authors: Hartmann Nicolai F. , Ma Xuedan , Htoon Han , Doorn Stephen K. 
Published: February 2020

Controlled low-level covalent functionalization of single-wall carbon nanotubes (SWCNTs) has refocused the attention of the nanophotonics community on the use of SWCNTs as promising building blocks in photonic circuits due to their recently discovered property of room temperature single photon emission.1 Further, these new emitting states introduced through chemically stable oxygen2 and aryl diazonium dopants3 exhibit a significant increase in photoluminescence (PL) quantum yield and sensitivity to their dielectric environment, which enables their use in imaging and sensor applications.4 However, successful integration into waveguide structures and other photonic circuits requires a comprehensive understanding of the angular emission behavior of these dopant sites. One powerful microscopy technique to study the angular emission properties of emitters is Back focal plane (BFP) imaging, which enables to distinguish different radiation channels5, to reveal emitter orientations6 and magnetic light properties7, amongst others.
We present a refinement of the covalent doping procedure2,3 to achieve the control of the doping level and type of dopant down to the introduction of individual dopant sites in a short timescale. At the same time this procedure is compatible with protocols for isolating chirality sorted and rather long SWCNTs8, which enables us to study the length dependence of the angular emission as a function of SWCNT length. In contrast, we also investigate the spatially localized emission from individual dopant sites along the SWCNTs to learn in which angles the emission occurs and to be able to design waveguides tailored specifically to the emission properties. Further we show the significant redirection of emission when placing doped SWCNTs on plasmonic gold thin films. Both, the pristine E
11 and the dopant E
11
*emission can launch different propagating surface plasmons along the metal interface. These plasmons can be coupled into propagating light via leakage radiation and observed in the BFP.

1 X. Ma, et. al., Nat.
Nanotechnol.
2015, 10, 671. 2 S. Ghosh, et al., Science, 2010,
330, 1656. 3 Y. Piao, et al., Nat. Chem., 2013, 5, 840. 4 H. Kwon, et. al., J. Phys. Chem. C
2015, 119, 3733. 5 N. F. Hartmann, et. al., ACS Nano
2013, 7, 10257. 6 A. Lieb, et. al., J. Opt. Soc. Am. B
2004, 21, 1210. 7 T. H. Taminiau et. al., Nat. Commun.
2012, 3, 979. 8 N. F. Hartmann, et. al., Nanoscale
2015, 7, 20521.
(Invited) Physics and Applications of Spontaneously Aligned Macroscopic Nanotube Assemblies
Authors: Gao Weilu , He Xiaowei , Zubair Ahmed , Komatsu Natsumi , Guo Cheng , Xie Lijuan , Kono Junichiro 
Published: February 2020

One of the outstanding challenges in nanotechnology is how to assemble individual nano-objects into macroscopic architectures while preserving their extraordinary properties. For example, the one-dimensional character of electrons in individual carbon nanotubes leads to extremely anisotropic transport, optical, and magnetic phenomena, but their macroscopic manifestations have been limited. Here, we describe novel methods for preparing macroscopic films, sheets, and fibers of highly aligned carbon nanotubes and their applications to basic and applied studies. Sufficiently thick films act as ideal terahertz polarizers, and appropriately doped films operate as polarization-sensitive, flexible, powerless, and ultrabroadband photodetectors. Together with recently developed chirality enrichment methods, these developments will allow us to probe, understand, and control dynamic conductivities of interacting one-dimensional electrons in macroscopic single crystals of single-chirality single-wall carbon nanotubes.
(Invited) Exciton Dissociation and Trion Generation in Individual Carbon Nanotubes
Authors: Kato Yuichiro K. 
Published: February 2020

Screening is limited in single-walled carbon nanotubes because of their one-dimensional nature, and the strong Coulomb interactions result in optical spectra dominated by excitons with binding energies lager than half an eV. Also because of the limited screening, a charged carrier can be bound to an exciton to form a trion that is stable at room temperature.
Here we discuss experiments aimed at highlighting the behaviors of excitons and trions under electric fields. Microspectroscopy measurements are performed on individual suspended carbon nanotubes integrated into field-effect devices. Simultaneous photoluminescence and photoconductivity spectroscopy show evidences for spontaneous dissociation [1], despite the expectation that free carrier generation from such a tightly-bound state would be difficult. As the field is increased, we observe an emergence of new absorption peaks in the excitation spectra, which can be explained by electrical activation of dark excited states [2]. Although trion formation has been thought to be difficult in suspended nanotubes due to low exciton-carrier scattering rates, we have succeeded in identifying trion emission under an application of gate voltages [3].
Work supported by KAKENHI, The Canon Foundation, The Asahi Glass Foundation, and the Photon Frontier Network Program of MEXT, Japan.
[1] Y. Kumamoto, M. Yoshida, A. Ishii, A. Yokoyama, T. Shimada, Y. K. Kato, Phys. Rev. Lett. 112, 117401 (2014).
[2] T. Uda, M. Yoshida, A. Ishii, Y. K. Kato, submitted.
[3] M. Yoshida, A. Popert, Y. K. Kato, arXiv:1510.08996.