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  • Wearable electronics: Nanomesh on-skin electronics
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-17 00:00:00
    John A. Rogers

    Hollow, nanoscale metal filaments in open-mesh architectures provide soft, shape-conformal electrical interfaces to the skin as the basis for high-precision, irritation-free sensing platforms.

    更新日期:2017-07-19
  • Controlling energy flow in multimetallic nanostructures for plasmonic catalysis
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-17 00:00:00
    Umar Aslam, Steven Chavez, Suljo Linic

    It has been shown that photoexcitation of plasmonic metal nanoparticles (Ag, Au and Cu) can induce direct photochemical reactions. However, the widespread application of this technology in catalysis has been limited by the relatively poor chemical reactivity of noble metal surfaces. Despite efforts to combine plasmonic and catalytic metals, the physical mechanisms that govern energy transfer from plasmonic metals to catalytic metals remain unclear. Here we show that hybrid core–shell nanostructures in which a core plasmonic metal harvests visible-light photons can selectively channel that energy into catalytically active centres on the nanostructure shell. To accomplish this, we developed a synthetic protocol to deposit a few monolayers of Pt onto Ag nanocubes. This model system allows us to conclusively separate the optical and catalytic functions of the hybrid nanomaterial and determine that the flow of energy is strongly biased towards the excitation of energetic charge carriers in the Pt shell. We demonstrate the utility of these nanostructures for photocatalytic chemical reactions in the preferential oxidation of CO in excess H2. Our data demonstrate that the reaction occurs exclusively on the Pt surface.

    更新日期:2017-07-19
  • Room-temperature continuous-wave lasing from monolayer molybdenum ditelluride integrated with a silicon nanobeam cavity
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-17 00:00:00
    Yongzhuo Li, Jianxing Zhang, Dandan Huang, Hao Sun, Fan Fan, Jiabin Feng, Zhen Wang, C. Z. Ning

    Monolayer transition-metal dichalcogenides (TMDs) have the potential to become efficient optical-gain materials for low-energy-consumption nanolasers with the smallest gain media because of strong excitonic emission. However, until now TMD-based lasing has been realized only at low temperatures. Here we demonstrate for the first time a room-temperature laser operation in the infrared region from a monolayer of molybdenum ditelluride on a silicon photonic-crystal cavity. The observation is enabled by the unique combination of a TMD monolayer with an emission wavelength transparent to silicon, and a high-Q cavity of the silicon nanobeam. The laser is pumped by a continuous-wave excitation, with a threshold density of 6.6 W cm–2. Its linewidth is as narrow as 0.202 nm with a corresponding Q of 5,603, the largest value reported for a TMD laser. This demonstration establishes TMDs as practical materials for integrated TMD–silicon nanolasers suitable for silicon-based nanophotonic applications in silicon-transparent wavelengths.

    更新日期:2017-07-19
  • Inflammation-free, gas-permeable, lightweight, stretchable on-skin electronics with nanomeshes
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-17 00:00:00
    Akihito Miyamoto, Sungwon Lee, Nawalage Florence Cooray, Sunghoon Lee, Mami Mori, Naoji Matsuhisa, Hanbit Jin, Leona Yoda, Tomoyuki Yokota, Akira Itoh, Masaki Sekino, Hiroshi Kawasaki, Tamotsu Ebihara, Masayuki Amagai, Takao Someya

    Thin-film electronic devices can be integrated with skin for health monitoring and/or for interfacing with machines. Minimal invasiveness is highly desirable when applying wearable electronics directly onto human skin. However, manufacturing such on-skin electronics on planar substrates results in limited gas permeability. Therefore, it is necessary to systematically investigate their long-term physiological and psychological effects. As a demonstration of substrate-free electronics, here we show the successful fabrication of inflammation-free, highly gas-permeable, ultrathin, lightweight and stretchable sensors that can be directly laminated onto human skin for long periods of time, realized with a conductive nanomesh structure. A one-week skin patch test revealed that the risk of inflammation caused by on-skin sensors can be significantly suppressed by using the nanomesh sensors. Furthermore, a wireless system that can detect touch, temperature and pressure is successfully demonstrated using a nanomesh with excellent mechanical durability. In addition, electromyogram recordings were successfully taken with minimal discomfort to the user.

    更新日期:2017-07-19
  • Electromagnetized gold nanoparticles mediate direct lineage reprogramming into induced dopamine neurons in vivo for Parkinson's disease therapy
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-17 00:00:00
    Junsang Yoo, Euiyeon Lee, Hee Young Kim, Dong-ho Youn, Junghyun Jung, Hongwon Kim, Yujung Chang, Wonwoong Lee, Jaein Shin, Soonbong Baek, Wonhee Jang, Won Jun, Soochan Kim, Jongki Hong, Hi-Joon Park, Christopher J. Lengner, Sang Hyun Moh, Youngeun Kwon, Jongpil Kim

    Electromagnetic fields (EMF) are physical energy fields generated by electrically charged objects, and specific ranges of EMF can influence numerous biological processes, which include the control of cell fate and plasticity. In this study, we show that electromagnetized gold nanoparticles (AuNPs) in the presence of specific EMF conditions facilitate an efficient direct lineage reprogramming to induced dopamine neurons in vitro and in vivo. Remarkably, electromagnetic stimulation leads to a specific activation of the histone acetyltransferase Brd2, which results in histone H3K27 acetylation and a robust activation of neuron-specific genes. In vivo dopaminergic neuron reprogramming by EMF stimulation of AuNPs efficiently and non-invasively alleviated symptoms in mouse Parkinson's disease models. This study provides a proof of principle for EMF-based in vivo lineage conversion as a potentially viable and safe therapeutic strategy for the treatment of neurodegenerative disorders.

    更新日期:2017-07-19
  • Band-edge engineering for controlled multi-modal nanolasing in plasmonic superlattices
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-10
    Danqing Wang, Ankun Yang, Weijia Wang, Yi Hua, Richard D. Schaller, George C. Schatz, Teri W. Odom

    Single band-edge states can trap light and function as high-quality optical feedback for microscale lasers and nanolasers. However, access to more than a single band-edge mode for nanolasing has not been possible because of limited cavity designs. Here, we describe how plasmonic superlattices—finite-arrays of nanoparticles (patches) grouped into microscale arrays—can support multiple band-edge modes capable of multi-modal nanolasing at programmed emission wavelengths and with large mode spacings. Different lasing modes show distinct input–output light behaviour and decay dynamics that can be tailored by nanoparticle size. By modelling the superlattice nanolasers with a four-level gain system and a time-domain approach, we reveal that the accumulation of population inversion at plasmonic hot spots can be spatially modulated by the diffractive coupling order of the patches. Moreover, we show that symmetry-broken superlattices can sustain switchable nanolasing between a single mode and multiple modes.

    更新日期:2017-07-11
  • Air-stable and freestanding lithium alloy/graphene foil as an alternative to lithium metal anodes
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-10
    Jie Zhao, Guangmin Zhou, Kai Yan, Jin Xie, Yuzhang Li, Lei Liao, Yang Jin, Kai Liu, Po-Chun Hsu, Jiangyan Wang, Hui-Ming Cheng, Yi Cui

    Developing high-capacity anodes is a must to improve the energy density of lithium batteries for electric vehicle applications. Alloy anodes are one promising option, but without pre-stored lithium, the overall energy density is limited by the low-capacity lithium metal oxide cathodes. Recently, lithium metal has been revived as a high-capacity anode, but faces several challenges owing to its high reactivity and uncontrolled dendrite growth. Here, we show a series of Li-containing foils inheriting the desirable properties of alloy anodes and pure metal anodes. They consist of densely packed LixM (M = Si, Sn, or Al) nanoparticles encapsulated by large graphene sheets. With the protection of graphene sheets, the large and freestanding LixM/graphene foils are stable in different air conditions. With fully expanded LixSi confined in the highly conductive and chemically stable graphene matrix, this LixSi/graphene foil maintains a stable structure and cyclability in half cells (400 cycles with 98% capacity retention). This foil is also paired with high-capacity Li-free V2O5 and sulfur cathodes to achieve stable full-cell cycling.

    更新日期:2017-07-11
  • Formula Nano
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-06

    Last April, six teams raced molecules on a metallic surface using a scanning tunnelling microscope in the first NanoCar Race. The event brought scientific research in nanotechnology to the attention of the wider public.

    更新日期:2017-07-06
  • The interface of nanoparticles with proliferating mammalian cells
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-06
    Einat Panet, Tal Mashriki, Roxane Lahmi, Abraham Jacob, Efrat Ozer, Manuela Vecsler, Itay Lazar, Amit Tzur

    更新日期:2017-07-06
  • Reply to 'The interface of nanoparticles with proliferating mammalian cells'
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-06
    Christoffer Åberg, Jong Ah Kim, Anna Salvati, Kenneth A. Dawson

    更新日期:2017-07-06
  • How to build and race a fast nanocar
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-06
    Grant J. Simpson, Víctor García-López, Philipp Petermeier, Leonhard Grill, James M. Tour

    The first NanoCar Race was an opportunity to see how far we have come in manipulating single molecules. As the team with the fastest molecule in this race, we share the synthetic challenges to building a fast nanocar and the experimental approach needed for rapid translation across a surface.

    更新日期:2017-07-06
  • The sounds of nanotechnology
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-06
    Norah Campbell, Cormac Deane, Padraig Murphy

    Public perceptions of nanotechnology are shaped by sound in surprising ways. Our analysis of the audiovisual techniques employed by nanotechnology stakeholders shows that well-chosen sounds can help to win public trust, create value and convey the weird reality of objects on the nanoscale.

    更新日期:2017-07-06
  • Why do we see history so differently?
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-06
    Chris Toumey

    Chris Toumey illustrates how different groups of people involved with nanotechnology have different views on the history of the field and feel differently about its importance.

    更新日期:2017-07-06
  • Our choice from the recent literature
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-06
    Wenjie Sun

    更新日期:2017-07-06
  • Ferroelectric tunnel junctions: Crossing the wall
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-10
    Evgeny Y. Tsymbal, Julian P. Velev

    The electronic transport across a head-to-head ferroelectric domain wall reveals a signature of quantum tunnelling assisted by confined, quantum-well-like states.

    更新日期:2017-07-06
  • Cancer immunotherapy: Making allies of phagocytes
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-24
    Steven Fiering

    A versatile nanovaccine platform is based on a synthetic nanoparticle that not only acts as an antigen carrier but also stimulates the STING pathway.

    更新日期:2017-07-06
  • Cancer therapy: Neutrophils traffic in cancer nanodrugs
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-19
    Satoru Osuka, Erwin G. Van Meir

    Neutrophils loaded with cationic liposomal paclitaxel migrate across the blood/brain barrier to deliver chemotherapeutic nanoparticles in the inflamed post-surgical tumour margin.

    更新日期:2017-07-06
  • Building membrane nanopores
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-06
    Stefan Howorka

    Membrane nanopores—hollow nanoscale barrels that puncture biological or synthetic membranes—have become powerful tools in chemical- and biosensing, and have achieved notable success in portable DNA sequencing. The pores can be self-assembled from a variety of materials, including proteins, peptides, synthetic organic compounds and, more recently, DNA. But which building material is best for which application, and what is the relationship between pore structure and function? In this Review, I critically compare the characteristics of the different building materials, and explore the influence of the building material on pore structure, dynamics and function. I also discuss the future challenges of developing nanopore technology, and consider what the next-generation of nanopore structures could be and where further practical applications might emerge.

    更新日期:2017-07-06
  • Energy-dependent path of dissipation in nanomechanical resonators
    Nature Nanotech. (IF 38.986) Pub Date : 2017-05-15
    Johannes Güttinger, Adrien Noury, Peter Weber, Axel Martin Eriksson, Camille Lagoin, Joel Moser, Christopher Eichler, Andreas Wallraff, Andreas Isacsson, Adrian Bachtold

    Energy decay measurements in nanomechanical graphene resonators reveal that the flow of energy takes different paths during the decay.

    更新日期:2017-07-06
  • Spectral focusing of broadband silver electroluminescence in nanoscopic FRET-LEDs
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-10
    Robin P. Puchert, Florian Steiner, Gerd Plechinger, Felix J. Hofmann, Ines Caspers, Johanna Kirschner, Philipp Nagler, Alexey Chernikov, Christian Schüller, Tobias Korn, Jan Vogelsang, Sebastian Bange, John M. Lupton

    The demonstration of energy transfer from hotspots of electroluminescent silver nanoparticles to a two-dimensional crystal overlayer of a transition-metal dichalcogenide provides a tunable, sub-diffraction, electrically driven light source.

    更新日期:2017-07-06
  • Amyloid fibril systems reduce, stabilize and deliver bioavailable nanosized iron
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-24
    Yi Shen, Lidija Posavec, Sreenath Bolisetty, Florentine M. Hilty, Gustav Nyström, Joachim Kohlbrecher, Monika Hilbe, Antonella Rossi, Jeannine Baumgartner, Michael B. Zimmermann, Raffaele Mezzenga

    Amyloid fibrils from food-grade proteins deliver nanostructured bioavailable iron without cytotoxicity or pathological side effects.

    更新日期:2017-07-06
  • A STING-activating nanovaccine for cancer immunotherapy
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-24
    Min Luo, Hua Wang, Zhaohui Wang, Haocheng Cai, Zhigang Lu, Yang Li, Mingjian Du, Gang Huang, Chensu Wang, Xiang Chen, Matthew R. Porembka, Jayanthi Lea, Arthur E. Frankel, Yang-Xin Fu, Zhijian J. Chen, Jinming Gao

    STING-activating nanoparticle vaccines achieve robust activation of tumour-specific T cells for cancer immunotherapy.

    更新日期:2017-07-06
  • Resonant electron tunnelling assisted by charged domain walls in multiferroic tunnel junctions
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-10
    Gabriel Sanchez-Santolino, Javier Tornos, David Hernandez-Martin, Juan I. Beltran, Carmen Munuera, Mariona Cabero, Ana Perez-Muñoz, Jesus Ricote, Federico Mompean, Mar Garcia-Hernandez, Zouhair Sefrioui, Carlos Leon, Steve J. Pennycook, Maria Carmen Muñoz, Maria Varela, Jacobo Santamaria

    The peculiar features of domain walls observed in ferroelectrics make them promising active elements for next-generation non-volatile memories, logic gates and energy-harvesting devices. Although extensive research activity has been devoted recently to making full use of this technological potential, concrete realizations of working nanodevices exploiting these functional properties are yet to be demonstrated. Here, we fabricate a multiferroic tunnel junction based on ferromagnetic La0.7Sr0.3MnO3 electrodes separated by an ultrathin ferroelectric BaTiO3 tunnel barrier, where a head-to-head domain wall is constrained. An electron gas stabilized by oxygen vacancies is confined within the domain wall, displaying discrete quantum-well energy levels. These states assist resonant electron tunnelling processes across the barrier, leading to strong quantum oscillations of the electrical conductance.

    更新日期:2017-07-06
  • A solid-state single-photon filter
    Nature Nanotech. (IF 38.986) Pub Date : 2017-05-15
    Lorenzo De Santis, Carlos Antón, Bogdan Reznychenko, Niccolo Somaschi, Guillaume Coppola, Jean Senellart, Carmen Gómez, Aristide Lemaître, Isabelle Sagnes, Andrew G. White, Loïc Lanco, Alexia Auffèves, Pascale Senellart

    A strong limitation of linear optical quantum computing is the probabilistic operation of two-quantum-bit gates based on the coalescence of indistinguishable photons. A route to deterministic operation is to exploit the single-photon nonlinearity of an atomic transition. Through engineering of the atom–photon interaction, phase shifters, photon filters and photon–photon gates have been demonstrated with natural atoms. Proofs of concept have been reported with semiconductor quantum dots, yet limited by inefficient atom–photon interfaces and dephasing. Here, we report a highly efficient single-photon filter based on a large optical nonlinearity at the single-photon level, in a near-optimal quantum-dot cavity interface. When probed with coherent light wavepackets, the device shows a record nonlinearity threshold around 0.3 ± 0.1 incident photons. We demonstrate that 80% of the directly reflected light intensity consists of a single-photon Fock state and that the two- and three-photon components are strongly suppressed compared with the single-photon one.

    更新日期:2017-07-06
  • Position-dependent and millimetre-range photodetection in phototransistors with micrometre-scale graphene on SiC
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-10
    Biddut K. Sarker, Edward Cazalas, Ting-Fung Chung, Isaac Childres, Igor Jovanovic, Yong P. Chen

    The extraordinary optical and electronic properties of graphene make it a promising component of high-performance photodetectors. However, in typical graphene-based photodetectors demonstrated to date, the photoresponse only comes from specific locations near graphene over an area much smaller than the device size. For many optoelectronic device applications, it is desirable to obtain the photoresponse and positional sensitivity over a much larger area. Here, we report the spatial dependence of the photoresponse in backgated graphene field-effect transistors (GFET) on silicon carbide (SiC) substrates by scanning a focused laser beam across the GFET. The GFET shows a nonlocal photoresponse even when the SiC substrate is illuminated at distances greater than 500 µm from the graphene. The photoresponsivity and photocurrent can be varied by more than one order of magnitude depending on the illumination position. Our observations are explained with a numerical model based on charge transport of photoexcited carriers in the substrate.

    更新日期:2017-07-06
  • Controlling propagation and coupling of waveguide modes using phase-gradient metasurfaces
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-17
    Zhaoyi Li, Myoung-Hwan Kim, Cheng Wang, Zhaohong Han, Sajan Shrestha, Adam Christopher Overvig, Ming Lu, Aaron Stein, Anuradha Murthy Agarwal, Marko Lončar, Nanfang Yu

    Research on two-dimensional designer optical structures, or metasurfaces, has mainly focused on controlling the wavefronts of light propagating in free space. Here, we show that gradient metasurface structures consisting of phased arrays of plasmonic or dielectric nanoantennas can be used to control guided waves via strong optical scattering at subwavelength intervals. Based on this design principle, we experimentally demonstrate waveguide mode converters, polarization rotators and waveguide devices supporting asymmetric optical power transmission. We also demonstrate all-dielectric on-chip polarization rotators based on phased arrays of Mie resonators with negligible insertion losses. Our gradient metasurfaces can enable small-footprint, broadband and low-loss photonic integrated devices.

    更新日期:2017-07-06
  • Scalable electrophysiology in intact small animals with nanoscale suspended electrode arrays
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-17
    Daniel L. Gonzales, Krishna N. Badhiwala, Daniel G. Vercosa, Benjamin W. Avants, Zheng Liu, Weiwei Zhong, Jacob T. Robinson

    Electrical measurements from large populations of animals would help reveal fundamental properties of the nervous system and neurological diseases. Small invertebrates are ideal for these large-scale studies; however, patch-clamp electrophysiology in microscopic animals typically requires invasive dissections and is low-throughput. To overcome these limitations, we present nano-SPEARs: suspended electrodes integrated into a scalable microfluidic device. Using this technology, we have made the first extracellular recordings of body-wall muscle electrophysiology inside an intact roundworm, Caenorhabditis elegans. We can also use nano-SPEARs to record from multiple animals in parallel and even from other species, such as Hydra littoralis. Furthermore, we use nano-SPEARs to establish the first electrophysiological phenotypes for C. elegans models for amyotrophic lateral sclerosis and Parkinson's disease, and show a partial rescue of the Parkinson's phenotype through drug treatment. These results demonstrate that nano-SPEARs provide the core technology for microchips that enable scalable, in vivo studies of neurobiology and neurological diseases.

    更新日期:2017-07-06
  • Neutrophil-mediated anticancer drug delivery for suppression of postoperative malignant glioma recurrence
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-19
    Jingwei Xue, Zekai Zhao, Lei Zhang, Lingjing Xue, Shiyang Shen, Yajing Wen, Zhuoyuan Wei, Lu Wang, Lingyi Kong, Hongbin Sun, Qineng Ping, Ran Mo, Can Zhang

    Cell-mediated drug-delivery systems have received considerable attention for their enhanced therapeutic specificity and efficacy in cancer treatment. Neutrophils (NEs), the most abundant type of immune cells, are known to penetrate inflamed brain tumours. Here we show that NEs carrying liposomes that contain paclitaxel (PTX) can penetrate the brain and suppress the recurrence of glioma in mice whose tumour has been resected surgically. Inflammatory factors released after tumour resection guide the movement of the NEs into the inflamed brain. The highly concentrated inflammatory signals in the brain trigger the release of liposomal PTX from the NEs, which allows delivery of PTX into the remaining invading tumour cells. We show that this NE-mediated delivery of drugs efficiently slows the recurrent growth of tumours, with significantly improved survival rates, but does not completely inhibit the regrowth of tumours.

    更新日期:2017-07-06
  • Peptide–MHC-based nanomedicines for autoimmunity function as T-cell receptor microclustering devices
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-24
    Santiswarup Singha, Kun Shao, Yang Yang, Xavier Clemente-Casares, Patricia Solé, Antonio Clemente, Jesús Blanco, Qin Dai, Fayi Song, Shang Wan Liu, Jun Yamanouchi, Channakeshava Sokke Umeshappa, Roopa Hebbandi Nanjundappa, Pascal Detampel, Matthias Amrein, César Fandos, Robert Tanguay, Susan Newbigging, Pau Serra, Anmar Khadra, Warren C. W. Chan, Pere Santamaria

    We have shown that nanoparticles (NPs) can be used as ligand-multimerization platforms to activate specific cellular receptors in vivo. Nanoparticles coated with autoimmune disease-relevant peptide-major histocompatibility complexes (pMHC) blunted autoimmune responses by triggering the differentiation and expansion of antigen-specific regulatory T cells in vivo. Here, we define the engineering principles impacting biological activity, detail a synthesis process yielding safe and stable compounds, and visualize how these nanomedicines interact with cognate T cells. We find that the triggering properties of pMHC–NPs are a function of pMHC intermolecular distance and involve the sustained assembly of large antigen receptor microclusters on murine and human cognate T cells. These compounds show no off-target toxicity in zebrafish embryos, do not cause haematological, biochemical or histological abnormalities, and are rapidly captured by phagocytes or processed by the hepatobiliary system. This work lays the groundwork for the design of ligand-based NP formulations to re-program in vivo cellular responses using nanotechnology.

    更新日期:2017-07-06
  • Fast and curious
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-06
    Rémy Pawlak, Tobias Meier

    Rémy Pawlak and Tobias Meier discuss how they got involved in the first international NanoCar Race and their impressions from this experience.

    更新日期:2017-07-06
  • Molecular diodes: Breaking the Landauer limit
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-03
    Nicolas Clement, Akira Fujiwara

    A diode made of a self-assembly monolayer with ferrocenyl termini shows an on/off ratio of ∼105.

    更新日期:2017-07-04
  • High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-03
    Shu-Jen Han, Jianshi Tang, Bharat Kumar, Abram Falk, Damon Farmer, George Tulevski, Keith Jenkins, Ali Afzali, Satoshi Oida, John Ott, James Hannon, Wilfried Haensch

    High-performance, CMOS-compatible ring-oscillators based on carbon nanotubes are fabricated by scalable and fully manufacturable processes.

    更新日期:2017-07-04
  • Photo-excited hot carrier dynamics in hydrogenated amorphous silicon imaged by 4D electron microscopy
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-03
    Bolin Liao, Ebrahim Najafi, Heng Li, Austin J. Minnich, Ahmed H. Zewail

    Scanning ultrafast electron microscopy provides new insights into hot carrier dynamics in amorphous semiconductors.

    更新日期:2017-07-04
  • Molecular diodes with rectification ratios exceeding 105 driven by electrostatic interactions
    Nature Nanotech. (IF 38.986) Pub Date : 2017-07-03
    Xiaoping Chen, Max Roemer, Li Yuan, Wei Du, Damien Thompson, Enrique del Barco, Christian A. Nijhuis

    Molecular diodes operating in the tunnelling regime are intrinsically limited to a maximum rectification ratio R of ∼103. To enhance this rectification ratio to values comparable to those of conventional diodes (R ≥ 105) an alternative mechanism of rectification is therefore required. Here, we report a molecular diode with R = 6.3 × 105 based on self-assembled monolayers with Fc–C≡C–Fc (Fc, ferrocenyl) termini. The number of molecules (n(V)) involved in the charge transport changes with the polarity of the applied bias. More specifically, n(V) increases at forward bias because of an attractive electrostatic force between the positively charged Fc units and the negatively charged top electrode, but remains constant at reverse bias when the Fc units are neutral and interact weakly with the positively charged electrode. We successfully model this mechanism using molecular dynamics calculations.

    更新日期:2017-07-04
  • Magnetic brightening and control of dark excitons in monolayer WSe2
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-26
    Xiao-Xiao Zhang, Ting Cao, Zhengguang Lu, Yu-Chuan Lin, Fan Zhang, Ying Wang, Zhiqiang Li, James C. Hone, Joshua A. Robinson, Dmitry Smirnov, Steven G. Louie, Tony F. Heinz

    Monolayer transition metal dichalcogenide crystals, as direct-gap materials with strong light–matter interactions, have attracted much recent attention. Because of their spin-polarized valence bands and a predicted spin splitting at the conduction band edges, the lowest-lying excitons in WX2 (X = S, Se) are expected to be spin-forbidden and optically dark. To date, however, there has been no direct experimental probe of these dark excitons. Here, we show how an in-plane magnetic field can brighten the dark excitons in monolayer WSe2 and permit their properties to be observed experimentally. Precise energy levels for both the neutral and charged dark excitons are obtained and compared with ab initio calculations using the GW-BSE approach. As a result of their spin configuration, the brightened dark excitons exhibit much-increased emission and valley lifetimes. These studies directly probe the excitonic spin manifold and reveal the fine spin-splitting at the conduction band edges.

    更新日期:2017-06-27
  • 2D materials: Brightening the dark excitons
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-26
    Kian Ping Loh

    Two independent methods using near-field coupling to surface plasmon polaritons and magnetic brightening allow the observation of dark excitons in WSe2.

    更新日期:2017-06-27
  • Probing dark excitons in atomically thin semiconductors via near-field coupling to surface plasmon polaritons
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-26
    You Zhou, Giovanni Scuri, Dominik S. Wild, Alexander A. High, Alan Dibos, Luis A. Jauregui, Chi Shu, Kristiaan De Greve, Kateryna Pistunova, Andrew Y. Joe, Takashi Taniguchi, Kenji Watanabe, Philip Kim, Mikhail D. Lukin, Hongkun Park

    Near-field coupling to surface plasmon polaritons enables the observation of spin-forbidden dark excitonic states in monolayer WSe2.

    更新日期:2017-06-27
  • Antigen-capturing nanoparticles improve the abscopal effect and cancer immunotherapy
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-26
    Yuanzeng Min, Kyle C. Roche, Shaomin Tian, Michael J. Eblan, Karen P. McKinnon, Joseph M. Caster, Shengjie Chai, Laura E. Herring, Longzhen Zhang, Tian Zhang, Joseph M. DeSimone, Joel E. Tepper, Benjamin G. Vincent, Jonathan S. Serody, Andrew Z. Wang

    Nanoparticles can be utilized to capture tumour antigens and improve their presentation, which in turn improves the efficacy of cancer immunotherapy.

    更新日期:2017-06-27
  • Neutrophil-mediated anticancer drug delivery for suppression of postoperative malignant glioma recurrence
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-19
    Jingwei Xue, Zekai Zhao, Lei Zhang, Lingjing Xue, Shiyang Shen, Yajing Wen, Zhuoyuan Wei, Lu Wang, Lingyi Kong, Hongbin Sun, Qineng Ping, Ran Mo, Can Zhang

    Cell-mediated drug-delivery systems have received considerable attention for their enhanced therapeutic specificity and efficacy in cancer treatment. Neutrophils (NEs), the most abundant type of immune cells, are known to penetrate inflamed brain tumours. Here we show that NEs carrying liposomes that contain paclitaxel (PTX) can penetrate the brain and suppress the recurrence of glioma in mice whose tumour has been resected surgically. Inflammatory factors released after tumour resection guide the movement of the NEs into the inflamed brain. The highly concentrated inflammatory signals in the brain trigger the release of liposomal PTX from the NEs, which allows delivery of PTX into the remaining invading tumour cells. We show that this NE-mediated delivery of drugs efficiently slows the recurrent growth of tumours, with significantly improved survival rates, but does not completely inhibit the regrowth of tumours.

    更新日期:2017-06-20
  • Sulfated glycopeptide nanostructures for multipotent protein activation
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-19
    Sungsoo S. Lee, Timmy Fyrner, Feng Chen, Zaida Álvarez, Eduard Sleep, Danielle S. Chun, Joseph A. Weiner, Ralph W. Cook, Ryan D. Freshman, Michael S. Schallmo, Karina M. Katchko, Andrew D. Schneider, Justin T. Smith, Chawon Yun, Gurmit Singh, Sohaib Z. Hashmi, Mark T. McClendon, Zhilin Yu, Stuart R. Stock, Wellington K. Hsu, Erin L. Hsu, Samuel I. Stupp

    Biological systems have evolved to utilize numerous proteins with capacity to bind polysaccharides for the purpose of optimizing their function. A well-known subset of these proteins with binding domains for the highly diverse sulfated polysaccharides are important growth factors involved in biological development and tissue repair. We report here on supramolecular sulfated glycopeptide nanostructures, which display a trisulfated monosaccharide on their surfaces and bind five critical proteins with different polysaccharide-binding domains. Binding does not disrupt the filamentous shape of the nanostructures or their internal β-sheet backbone, but must involve accessible adaptive configurations to interact with such different proteins. The glycopeptide nanostructures amplified signalling of bone morphogenetic protein 2 significantly more than the natural sulfated polysaccharide heparin, and promoted regeneration of bone in the spine with a protein dose that is 100-fold lower than that required in the animal model. These highly bioactive nanostructures may enable many therapies in the future involving proteins.

    更新日期:2017-06-20
  • Monitoring the orientation of rare-earth-doped nanorods for flow shear tomography
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-19
    Jongwook Kim, Sébastien Michelin, Michiel Hilbers, Lucio Martinelli, Elodie Chaudan, Gabriel Amselem, Etienne Fradet, Jean-Pierre Boilot, Albert M. Brouwer, Charles N. Baroud, Jacques Peretti, Thierry Gacoin

    Rare-earth phosphors exhibit unique luminescence polarization features originating from the anisotropic symmetry of the emitter ion's chemical environment. However, to take advantage of this peculiar property, it is necessary to control and measure the ensemble orientation of the host particles with a high degree of precision. Here, we show a methodology to obtain the photoluminescence polarization of Eu-doped LaPO4 nanorods assembled in an electrically modulated liquid-crystalline phase. We measure Eu3+ emission spectra for the three main optical configurations (σ, π and α, depending on the direction of observation and the polarization axes) and use them as a reference for the nanorod orientation analysis. Based on the fact that flowing nanorods tend to orient along the shear strain profile, we use this orientation analysis to measure the local shear rate in a flowing liquid. The potential of this approach is then demonstrated through tomographic imaging of the shear rate distribution in a microfluidic system.

    更新日期:2017-06-20
  • Cancer therapy: Neutrophils traffic in cancer nanodrugs
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-19
    Satoru Osuka, Erwin G. Van Meir

    Neutrophils loaded with cationic liposomal paclitaxel migrate across the blood/brain barrier to deliver chemotherapeutic nanoparticles in the inflamed post-surgical tumour margin.

    更新日期:2017-06-20
  • Ultracoherent nanomechanical resonators via soft clamping and dissipation dilution
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-12
    Y. Tsaturyan, A. Barg, E. S. Polzik, A. Schliesser

    The small mass and high coherence of nanomechanical resonators render them the ultimate mechanical probe, with applications that range from protein mass spectrometry and magnetic resonance force microscopy to quantum optomechanics. A notorious challenge in these experiments is the thermomechanical noise related to the dissipation through internal or external loss channels. Here we introduce a novel approach to define the nanomechanical modes, which simultaneously provides a strong spatial confinement, full isolation from the substrate and dilution of the resonator material's intrinsic dissipation by five orders of magnitude. It is based on a phononic bandgap structure that localizes the mode but does not impose the boundary conditions of a rigid clamp. The reduced curvature in the highly tensioned silicon nitride resonator enables a mechanical Q > 108 at 1 MHz to yield the highest mechanical Qf products (>1014 Hz) yet reported at room temperature.

    更新日期:2017-06-13
  • Two-dimensional non-volatile programmable p–n junctions
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-12
    Dong Li, Mingyuan Chen, Zhengzong Sun, Peng Yu, Zheng Liu, Pulickel M. Ajayan, Zengxing Zhang

    Semiconductor p–n junctions are the elementary building blocks of most electronic and optoelectronic devices. The need for their miniaturization has fuelled the rapid growth of interest in two-dimensional (2D) materials. However, the performance of a p–n junction considerably degrades as its thickness approaches a few nanometres and traditional technologies, such as doping and implantation, become invalid at the nanoscale. Here we report stable non-volatile programmable p–n junctions fabricated from the vertically stacked all-2D semiconductor/insulator/metal layers (WSe2/hexagonal boron nitride/graphene) in a semifloating gate field-effect transistor configuration. The junction exhibits a good rectifying behaviour with a rectification ratio of 104 and photovoltaic properties with a power conversion efficiency up to 4.1% under a 6.8 nW light. Based on the non-volatile programmable properties controlled by gate voltages, the 2D p–n junctions have been exploited for various electronic and optoelectronic applications, such as memories, photovoltaics, logic rectifiers and logic optoelectronic circuits.

    更新日期:2017-06-13
  • Electrical tuning of a quantum plasmonic resonance
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-12
    Xiaoge Liu, Ju-Hyung Kang, Hongtao Yuan, Junghyun Park, Soo Jin Kim, Yi Cui, Harold Y. Hwang, Mark L. Brongersma

    A blue shift in the surface plasmon resonance of an indium tin oxide layer is observed—and electrically tuned—where a classical description would predict a red shift.

    更新日期:2017-06-13
  • Photodetectors: A heated junction
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-12
    Ming Zhou, Zongfu Yu

    Resonant photonic structures made of thermoelectric materials can convert light into electricity without wavelength limitations.

    更新日期:2017-06-13
  • Sub-10-nm patterning via directed self-assembly of block copolymer films with a vapour-phase deposited topcoat
    Nature Nanotech. (IF 38.986) Pub Date : 2017-03-27

    Directed self-assembly (DSA) of the domain structure in block copolymer (BCP) thin films is a promising approach for sub-10-nm surface patterning. DSA requires the control of interfacial properties on both interfaces of a BCP film to induce the formation of domains that traverse the entire film with a perpendicular orientation. Here we show a methodology to control the interfacial properties of BCP films that uses a polymer topcoat deposited by initiated chemical vapour deposition (iCVD). The iCVD topcoat forms a crosslinked network that grafts to and immobilizes BCP chains to create an interface that is equally attractive to both blocks of the underlying copolymer. The topcoat, in conjunction with a chemically patterned substrate, directs the assembly of the grating structures in BCP films with a half-pitch dimension of 9.3 nm. As the iCVD topcoat can be as thin as 7 nm, it is amenable to pattern transfer without removal. The ease of vapour-phase deposition, applicability to high-resolution BCP systems and integration with pattern-transfer schemes are attractive properties of iCVD topcoats for industrial applications.

    更新日期:2017-06-06
  • Magnetic polaron on dangling-bond spins in CdSe colloidal nanocrystals
    Nature Nanotech. (IF 38.986) Pub Date : 2017-03-13

    Non-magnetic colloidal nanostructures can demonstrate magnetic properties typical for diluted magnetic semiconductors because the spins of dangling bonds at their surface can act as the localized spins of magnetic ions. Here we report the observation of dangling-bond magnetic polarons (DBMPs) in 2.8-nm diameter CdSe colloidal nanocrystals (NCs). The DBMP binding energy of 7 meV is measured from the spectral shift of the emission lines under selective laser excitation. The polaron formation at low temperatures occurs by optical orientation of the dangling-bond spins (DBSs) that result from dangling-bond-assisted radiative recombination of spin-forbidden dark excitons. Modelling of the temperature dependence of the DBMP-binding energy and emission intensity shows that the DBMP is composed of a dark exciton and about 60 DBSs. The exchange integral of one DBS with the electron confined in the NC is ∼0.12 meV.

    更新日期:2017-06-06
  • Quantized edge modes in atomic-scale point contacts in graphene
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-03

    The zigzag edges of single- or few-layer graphene are perfect one-dimensional conductors owing to a set of gapless states that are topologically protected against backscattering. Direct experimental evidence of these states has been limited so far to their local thermodynamic and magnetic properties, determined by the competing effects of edge topology and electron–electron interaction. However, experimental signatures of edge-bound electrical conduction have remained elusive, primarily due to the lack of graphitic nanostructures with low structural and/or chemical edge disorder. Here, we report the experimental detection of edge-mode electrical transport in suspended atomic-scale constrictions of single and multilayer graphene created during nanomechanical exfoliation of highly oriented pyrolytic graphite. The edge-mode transport leads to the observed quantization of conductance close to multiples of G0 = 2e2/h. At the same time, conductance plateaux at G0/2 and a split zero-bias anomaly in non-equilibrium transport suggest conduction via spin-polarized states in the presence of an electron–electron interaction.

    更新日期:2017-06-06
  • Collective helicity switching of a DNA–coat assembly
    Nature Nanotech. (IF 38.986) Pub Date : 2017-03-27

    A virus-like artificial structure responds to variations in pH by switching helicity.

    更新日期:2017-06-06
  • Tunable sieving of ions using graphene oxide membranes
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-03

    Ion permeation and selectivity of graphene oxide membranes with sub-nm channels dramatically alters with the change in interlayer distance due to dehydration effects whereas permeation of water molecules remains largely unaffected.

    更新日期:2017-06-06
  • Dual-light control of nanomachines that integrate motor and modulator subunits
    Nature Nanotech. (IF 38.986) Pub Date : 2017-03-20

    A set of independently light-controlled motor and modulator subunits embedded in a polymer gel matrix enables controlled macroscopic expansion and retraction of the material.

    更新日期:2017-06-06
  • Revealing the reaction mechanisms of Li–O2 batteries using environmental transmission electron microscopy
    Nature Nanotech. (IF 38.986) Pub Date : 2017-03-27

    In situ characterization of the full reaction pathways of a solid state LiO2 battery shows the formation of hollow nanostructures as a result of the interplay between lithium ion diffusion, electron transport and oxygen gas evolution at the cathode.

    更新日期:2017-06-06
  • Water remediation: A steam nanogenerator
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-06

    更新日期:2017-06-06
  • Nanomachines: A light-powered clockwork
    Nature Nanotech. (IF 38.986) Pub Date : 2017-03-20

    An organogel is made of molecular motors and modulators that act cooperatively to perform a full mechanical cycle of contraction and expansion at the macroscale.

    更新日期:2017-06-06
  • Lithium–oxygen batteries: The reaction mechanism revealed
    Nature Nanotech. (IF 38.986) Pub Date : 2017-03-27

    Using in situ environmental transmission electron microscopy, the structural and phase changes of the reaction products of an air cathode during discharging and charging can be visualized in real time.

    更新日期:2017-06-06
  • Thermal desalination membranes: Carbon nanotubes keep up the heat
    Nature Nanotech. (IF 38.986) Pub Date : 2017-05-29

    Applying high-potential alternating current to a carbon-nanotube–polymer composite film provides a self-heating membrane that enhances desalination performance of high-salinity brines by membrane distillation.

    更新日期:2017-06-06
  • Ion sieving and desalination: Energy penalty for excess baggage
    Nature Nanotech. (IF 38.986) Pub Date : 2017-04-03

    Permeation experiments and simulations show that physically confined graphene oxide allows water molecules to pass through while hindering hydrated ions

    更新日期:2017-06-06
  • Our choice from the recent literature
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-06

    更新日期:2017-06-06
  • More carbon and less salt
    Nature Nanotech. (IF 38.986) Pub Date : 2017-06-06

    We take a closer look at recent developments in research on various strategies to use carbon nanostructures for water desalination.

    更新日期:2017-06-06
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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