Nano Letters

Publisher: American Chemical Society, American Chemical Society

Description

A central forum for scientists involved in nanoscale research, among a wide range of disciplines that include physical and materials chemistry, biotechnology, and applied physics. Nano Letters reports on fundamental research in all branches of the theory and practice of nanoscience and nanotechnology. It will provide rapid disclosure of the key elements of a study, publishing preliminary, experimental, and theoretical results on the physical, chemical, and biological phenomena, processes and applications of structures within the nanoscale range. Areas of interest include: Synthesis and processing of organic, inorganic, and hybrid nanosized materials by physical, chemical, and biological methods; Modeling and simulation of synthetic, assembly, and interaction processes; Characterization of unique size properties; Realization and application of novel nanostructures and nanodevices. This is the second letters journal launched by ACS, following the 1999 release of Organic Letters, and charged with the same mission: To rapidly communicate preliminary significant research results.

  • Impact factor
    13.03
  • 5-year impact
    14.13
  • Cited half-life
    4.40
  • Immediacy index
    2.47
  • Eigenfactor
    0.37
  • Article influence
    5.19
  • Website
    Nano Letters website
  • Other titles
    Nano letters (Online), Nano letters
  • ISSN
    1530-6992
  • OCLC
    44445939
  • Material type
    Document, Periodical, Internet resource
  • Document type
    Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

American Chemical Society

  • Pre-print
    • Author cannot archive a pre-print version
  • Restrictions
    • Must obtain written permission from Editor
    • Must not violate ACS ethical Guidelines
  • Post-print
    • Author cannot archive a post-print version
  • Restrictions
    • If mandated by funding agency or employer/ institution
    • Must obtain written permission from Editor confirming posting does not conflict prior publication policies
    • If mandated to deposit before 12 months, must obtain waiver from Institution/ Agency or use AuthorChoice
    • 12 months
  • Conditions
    • On website or repositories
    • Non-Commercial
    • Must be accompanied by set statement (see policy)
    • Must link to publisher version
    • If mandated sooner than 12 months, must obtain waiver from Editors or use AuthorChoice
    • Publisher's version/PDF may be used, but only via AuthorChoice option
  • Classification
    ​ white

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Fluorescent nanosensor probes have suffered from limited molecular recognition and a dearth of strategies for spatial-temporal operation in cell culture. In this work, we spatially imaged the dynamics of nitric oxide (NO) signaling, important in numerous pathologies and physiological functions, using intracellular near-infrared fluorescent single-walled carbon nanotubes (SWCNT). The observed spatial-temporal NO signaling gradients clarify and refine the existing paradigm of NO signaling based on averaged local concentrations. This work enables the study of transient intracellular phenomena associated with signaling and therapeutics.
    Nano Letters 07/2014;
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    ABSTRACT: The combination of micropillar array technology to measure cellular traction forces with super-resolution imaging allowed us to obtain cellular traction force maps and simultaneously zoom in on individual focal adhesions with single-molecule accuracy. We achieved a force detection precision of 500 pN simultaneously with a mean single-molecule localization precision of 30 nm. Key to the achievement was a two-step etching process that provided an integrated spacer next to the micropillar array, that permitted stable and reproducible observation of cells on micropillars within the short working distance of a high-magnification, high numerical aperture objective. In turn we used the technology to characterize the super-resolved structure of focal adhesions during force exertion. Live-cell imaging on MCF-7 cells demonstrated the applicability of the inverted configuration of the micropillar arrays to dynamics measurements. The smallest structural features of focal adhesions, however, could not be resolved by diffraction-limited microscopy. Forces emanated from a molecular base that was localized on top of the micropillars. What appeared as a single adhesion in conventional microscopy were in fact multiple elongated adhesions emanating from only a small fraction of the adhesion on the micropillar surface. Focal adhesions were elongated in the direction of local cellular force exertion with structural features of 100-280 nm in 3T3 Fibroblasts and MCF-7 cells. The combined measure of nanoscale architecture and force exerted shows a high level of stress accumulation at a single site of adhesion.
    Nano Letters 07/2014;
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    ABSTRACT: We record sequences of Raman spectra at a plasmonic junction formed by a gold AFM tip in contact with a silver surface coated with 4,4’-dimercaptostilbene (DMS). A 2D correlation analysis of the recorded trajectories reveals that the observable vibrational states can be divided into sub-sets, by virtue of the symmetry of DMS (C2h). The first set comprises the totally symmetric vibrations of DMS (ag) that are neither correlated with each other nor with the fluctuating background, assigned to the signature of charge transfer plasmons mediated by DMS. The second set consists of bu modes, which are correlated both with each other and with the background. Our findings are rationalized on the basis of the charge-transfer theory of Raman scattering, and illustrate how current carrying plasmons modulate the vibronic coupling terms from which the intensities of the bu states are derived. In effect, this study identifies gateway molecular modes for mediating charge shuttling across a plasmonic gap.
    Nano Letters 06/2014;
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    ABSTRACT: We validate the non-spherical grafting arrangement of isotropically coated spherical nanoparticles as very recently proposed. We utilize localized surface plasmon resonance enhanced dynamic polarized and depolarized light scattering from Au nanoparticles, the spherical symmetry of which was revealed by single-particle dark field spectroscopy. The same Au nanospheres are grafted with ligands of different chemistry and length. The wavelength dependent depolarization ratio and the two transport coefficients of these nanoparticles, obtained from the dynamic light scattering experiment, can only be reconciled with the TEM data, the single UV/Vis extinction spectrum, and the dark field spectroscopy experiments if their coating is described as asymmetric. Spatially anisotropic graft distribution on spherical nanoparticles impacts their assembly and understanding its origin will help control the structure and properties of polymer nanocomposites.
    Nano Letters 06/2014;
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    ABSTRACT: The hydration of graphene oxide (GO) membranes is the key to understand their remarkable selectivity in permeation of water molecules and humidity dependent gas separation. We investigated the hydration of single GO layers as a function of humidity using Scanning Force Microscopy (SFM). We determine the single interlayer distance from the step height of a single GO layer on top of one or two GO layers. This interlayer distance grows gradually by approximately 1Å upon a relative humidity (RH) increase in the range of 2 to ~80%. Immersion into liquid water increases the interlayer distance further by another 3Å. The gradual expansion of the single interlayer distance is in a good agreement with the averaged distance measured by X-ray diffraction on multilayered graphite oxides, which is commonly explained with an interstratification model. However, our experimental design excludes effects connected to interstratification. Instead we determine directly if insertion of water into GO occurs strictly by monolayers or the thickness of GO layers changes gradually. We find that hydration with up to 80% RH is a continuous process of incorporation of water molecules into single GO layers, while liquid water inserts as monolayers. The similarity of hydration for our bilayer and previously reported multilayered materials implies GO few and even bilayers to be suitable for selective water transport.
    Nano Letters 06/2014;
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    ABSTRACT: Advanced nanostructured materials, such as gold nanoparticles, magnetic nanoparticles and multifunctional materials, are nowadays used in many state-of-the-art biomedical application. However, although the engineering in this field is very advanced, there remain some fundamental problems involving the interaction mechanisms between nanostructures and cells or tissues. Here we show the potential of 1H-NMR in the investigation of the uptake of two different kinds of nanostructures i.e. maghemite and gold nanoparticles, and of a chemotherapy drug (temozolomide), in glioblastoma tumor cells. The proposed experimental protocol provides a new way to investigate the general problem of cellular uptake for a variety of biocompatible nanostructures and drugs.
    Nano Letters 06/2014; 14(7):3959-3965.
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    ABSTRACT: Theoretical calculations have predicted that extreme strains (>10%) in graphene would result in novel applications. However, up to now the highest reported strain reached ~1.3%. Here, we demonstrate uniaxial strains >10% by pulling graphene using a tensile-MEMS. To prevent it from slipping away, it was locally clamped with epoxy using a femtopipette. The results were analysed using Raman spectroscopy and optical tracking. Furthermore, analysis proved the process to be reversible and non-destructive for the graphene.
    Nano Letters 05/2014;
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    ABSTRACT: Strain engineering is ubiquitous in design and fabrication of innovative, high-performance electronic, optoelectronic, and photovoltaic devices. The increasing importance of strain-engineered nanoscale materials has raised significant challenges at both fabrication and characterization levels. Raman Scattering Spectroscopy (RSS) is one of the most straightforward techniques that have been broadly utilized to estimate the strain in semiconductors. However, this technique is incapable of measuring the individual components of stress thus only providing the average values of the in-plane strain. This inherit limitation severely diminishes the importance of RSS analysis and makes it ineffective in the predominant case of nanostructures and devices with nonuniform distribution of strain. Herein, we circumvent this major limitation and demonstrate for the first time the application of RSS to simultaneously probe the two local stress in-plane components in individual ultrathin silicon nanowires based on the imaging of the splitting of the two forbidden transverse optical phonons.
    Nano Letters 05/2014;
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    ABSTRACT: Inspired by the fantastic and fast-growing wearable electronics such as Google Glass and Apple iWatch, matchable lightweight and weaveable energy storage systems are urgently demanded while remaining as a bottleneck in the whole technology. Fiber-shaped energy storage devices that can be woven into electronic textiles may represent a general and effective strategy to overcome the above difficulty. Here a coaxial fiber lithium-ion battery has been achieved by sequentially winding aligned carbon nanotube composite yarn cathode and anode onto a cotton fiber. Novel yarn structures are designed to enable a high performance with a linear energy density of 0.75 mWh cm(-1). A wearable energy storage textile is also produced with an areal energy density of 4.5 mWh cm(-2).
    Nano Letters 05/2014;
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    ABSTRACT: Laser reduction of graphene oxide (GO) offers unique opportunities for the rapid, non-chemical production of graphene. By tuning relevant reduction parameters, the band gap and conductivity of reduced GO can be precisely controlled. In situ monitoring of single layer GO reduction is therefore essential. In this report, we show the direct observation of laser-induced, single layer GO reduction through correlated changes to its absorption and emission. Absorption/emission movies illustrate the initial stages of single layer GO reduction, its transition to reduced-GO (rGO) as well as its subsequent decomposition upon prolonged laser illumination. These studies reveal GO's photoreduction life cycle and through it native GO/rGO absorption coefficients, their intrasheet distributions as well as their spatial heterogeneities. Extracted absorption coefficients for unreduced GO are α405nm≈6±1×10(4) cm(-1), α520nm≈2.1±0.4×10(4) cm(-1) and α640nm≈1.1±0.3×10(4) cm(-1) while corresponding rGO α-values are α405nm≈21.6±0.6×10(4) cm(-1), α520nm≈16.9±0.4×10(4) cm(-1) and α640nm≈14.5±0.4×10(4) cm(-1). More importantly, the correlated absorption/emission imaging provides us with unprecedented insight into GO's underlying photoreduction mechanism, given our ability to spatially resolve its kinetics and to connect local rate constants to activation energies. On a broader level, the developed absorption imaging is general and can be applied towards investigating the optical properties of other two dimensional materials, especially those that are non-emissive and which are invisible to current single molecule optical techniques.
    Nano Letters 05/2014;
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    ABSTRACT: Carbonaceous materials have great potential for applications as anodes of alkali-metal ion batteries, such as Na-ion batteries and K-ion batteries (NIB and KIBs). We conduct an in situ study of the electrochemically-driven sodiation and potassiation of individual carbon nanofibers (CNFs) by transmission electron microscopy (TEM). The CNFs are hollow and consist of a bilayer wall with an outer layer of disordered-carbon (d-C) enclosing an inner layer of crystalline-carbon (c-C). The d-C exhibits about three times volume expansion of the c-C after full sodiation or potassiation, thus suggesting a much higher storage capacity of Na or K ions in d-C than c-C. For the bilayer CNF-based electrode, a steady sodium capacity of 245 mAh/g is measured with a Coulombic efficiency approaching 98% after a few initial cycles. The in situ TEM experiments also reveal the mechanical degradation of CNFs through formation of longitudinal cracks near the c-C/d-C interface during sodiation and potassiation. Geometrical changes of the tube are explained by a chemomechanical model using the anisotropic sodiation/potassiation strains in c-C and d-C. Our results provide mechanistic insights into the electrochemical reaction, microstructure evolution and mechanical degradation of carbon-based anodes during sodiation and potassiation, shedding light onto the development of carbon-based electrodes for NIBs and KIBs.
    Nano Letters 05/2014;
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    ABSTRACT: Because of their considerable science and technical interest, nanodiamonds (3-5 nm) are often used as a model to study the phase transformation between graphite and diamond. Here we demonstrated that a reversible nanodiamond-carbon onion phase transformation can be come true when laser irradiates colloidal suspen¬sions of nanodiamonds at the ambient temperature and pressure. Nanodiamonds are firstly transformed to carbon onions driven by the laser-induced high temperature, in which an intermediary bucky diamond phase is observed. Sequentially, carbon onions are transformed back to nanodiamonds driven by the laser-induced high temperature and high pressure from carbon onions as nanoscaled temperature and pressure cell upon the laser irradiation process in liquid. Similarly, the same bucky diamond phase serving as an intermediate phase is found during the carbon onion-to-nanodiamond transition. To have a clear insight into the unique phase transformation, the thermodynamic approaches on the nanoscale were proposed to elucidate the reversible phase transformation of nanodiamond-to-carbon onion-to-nanodiamond via an intermediary bucky diamond phase upon the laser irradiation in liquid. This reversible transition reveals a series of phase transformations between diamond and carbon allotropes such as carbon onion and bucky diamond, having a general insight into the basic physics involved in these phase transformations. These results give a clew to the root of meteoritic nanodiamonds which are commonly found in primitive meteorites but their origin is puzzling, and offer one suitable approach for breaking controllable pathways between diamond and carbon allotropes.
    Nano Letters 05/2014;
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    ABSTRACT: We demonstrate a solid-state nanopore assay for the unambiguous discrimination and quantification of modified DNA. Individual streptavidin proteins are employed as high-affinity tags for DNA containing a single biotin moiety. We establish that the rate of translocation events corresponds directly to relative concentration of protein-DNA complexes and use the selectivity of our approach to quantify modified oligonucleotides from among a background of unmodified DNA in solution.
    Nano Letters 05/2014;
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    ABSTRACT: We report the development of a multifunctional, solar-powered photoelectrochemical-pseudocapacitive-sensing material system for simultaneous solar energy conversion, electrochemical energy storage and chemical detection. The TiO2 nanowire/NiO nanoflakes and the Si nanowire/Pt nanoparticle composites are used as photoanode and photocathode, respectively. A stable open-circuit voltage of ~ 0.45 V and a high pseudocapacitance of up to ~ 455 F/g are obtained, which also exhibit repeating charging-discharging capability. The PEC-pseudocapacitive device is fully solar powered, without the need of any external power supply. Moreover, this TiO2 nanowire/NiO nanoflake composite photoanode exhibits excellent glucose sensitivity and selectivity. Under the sun light illumination, the PEC photocurrent shows a sensitive increase upon different glucose addition. While in the dark, the open-circuit voltage of the charged pseudocapacitor also exhibits corresponding signal over glucose analyte, thus serving as a full solar-powered energy conversion-storage-utilization system.
    Nano Letters 05/2014;
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    ABSTRACT: A load-bearing, multifunctional material with the simultaneous capability to store energy and withstand static and dynamic mechanical stresses is demonstrated. This is produced using ion-conducting polymers infiltrated into nanoporous silicon that is etched directly into bulk conductive silicon. This device platform maintains energy densities near 10 Wh/Kg with Coulombic efficiency of 98% under exposure to over 300 kPa tensile stresses, and 80 g vibratory accelerations, among excellent performance in other shear, compression, and impact tests. This demonstrates performance feasibility as a structurally integrated energy storage material broadly applicable across renewable energy systems, transportation systems, and mobile electronics, among others.
    Nano Letters 05/2014;

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