Latest Articles Include:
- 'Plenty of room' revisited
- Nature nanotechnology 4(12):781 (2009)
Who was Richard Feynman and what did he actually say about nanotechnology? - Plenty of room, plenty of history
Toumey C - Nature nanotechnology 4(12):783-784 (2009)
A 1959 lecture by Richard Feynman has become an important document in the history of nanotechnology but, as Chris Toumey reports, there are disagreements about when it became important, and why. - Feynman's unfinished business
Jones R - Nature nanotechnology 4(12):785 (2009)
Irrespective of what he got right and what he got wrong in his famous 1959 lecture, Richard Feynman's vision and imagination have had an important role in the development of nanoscience and nanotechnology, as Richard Jones reports. - Surely you're happy, Mr Feynman!
Segal M - Nature nanotechnology 4(12):786-788 (2009)
In 1959 Richard Feynman called for researchers to improve the resolution of the electron microscope, and they have — but resolution is only part of the story. - Will the public swallow nanofood?
Chun AL - Nature nanotechnology 4(12):790-791 (2009)
Nanotechnology could have an impact on many areas of the food industry, including packaging, nutrient delivery and food quality, but it is too early to tell if it will be embraced by food companies and the general public. - Our choice from the recent literature
- Nature nanotechnology 4(12):792-793 (2009)
Graphene: Fractionally clean Superconductors: Plane to see Nanowire sensors: Plasmon potential Catalysis: Enlightened coverage Optomechanics: Light reading Nanocontainers: Clean and spotless art Carbon nanotubes: Safe production? - Top down bottom up: Perfect match
- Nature nanotechnology 4(12):793 (2009)
Researchers in Liverpool have found a unique way to unite the physical and biological sciences. - Nanotoxicology: Damaging DNA from a distance
Myllynen P - Nature nanotechnology 4(12):795-796 (2009)
Nanoparticles can have an adverse impact on cells, even when there is a barrier between the cells and the source of the nanoparticles. Both direct and indirect effects should therefore be included in assessments of nanoparticle safety. - Measurement: Facing Heisenberg at the nanoscale
Clerk A - Nature nanotechnology 4(12):796-798 (2009)
By measuring the motion of a nanomechanical oscillator with an extremely small error, researchers have passed a milestone on the road to measurements of position at the ultimate limit set by quantum mechanics. - Nanomedicine: Detecting rare cancer cells
Zemp RJ - Nature nanotechnology 4(12):798-799 (2009)
Magnetic nanoparticles and gold-plated carbon nanotubes allow rapid detection of circulating tumour cells in the blood vessels of mice using two-colour photoacoustic methods. - Plasmonics: Gee whiz
Segal M - Nature nanotechnology 4(12):799 (2009)
An object possesses handedness (or chirality) if its mirror image cannot be superimposed on it. Circularly polarized light can also be left-handed or right-handed, and these two chiralities have been shown to give rise to different plasmon modes in nanostructures. - Processing: Superacids offer nanotube solution
Windle A - Nature nanotechnology 4(12):800-801 (2009)
Single-walled carbon nanotubes can be dissolved in superacids to produce solutions that should make it easier to process nanotubes into bulk structures. - Atomic force microscopy as a tool for atom manipulation
Custance O Perez R Morita S - Nature nanotechnology 4(12):803-810 (2009)
During the past 20 years, the manipulation of atoms and molecules at surfaces has allowed the construction and characterization of model systems that could, potentially, act as building blocks for future nanoscale devices. The majority of these experiments were performed with scanning tunnelling microscopy at cryogenic temperatures. Recently, it has been shown that another scanning probe technique, the atomic force microscope, is capable of positioning single atoms even at room temperature. Here, we review progress in the manipulation of atoms and molecules with the atomic force microscope, and discuss the new opportunities presented by this technique. - Nanotube electronics for radiofrequency applications
Rutherglen C Jain D Burke P - Nature nanotechnology 4(12):811-819 (2009)
Electronic devices based on carbon nanotubes are among the candidates to eventually replace silicon-based devices for logic applications. Before then, however, nanotube-based radiofrequency transistors could become competitive for high-performance analogue components such as low-noise amplifiers and power amplifiers in wireless systems. Single-walled nanotubes are well suited for use in radiofrequency transistors because they demonstrate near-ballistic electron transport and are expected to have high cut-off frequencies. To achieve the best possible performance it is necessary to use dense arrays of semiconducting nanotubes with good alignment between the nanotubes, but techniques that can economically manufacture such arrays are needed to realize this potential. Here we review progress towards nanotube electronics for radiofrequency applications in terms of device physics, circuit design and the manufacturing challenges. - Nanomechanical motion measured with an imprecision below that at the standard quantum limit
Teufel JD Donner T Castellanos-Beltran MA Harlow JW Lehnert KW - Nature nanotechnology 4(12):820-823 (2009)
Nanomechanical oscillators are at the heart of ultrasensitive detectors of force1, mass2 and motion3, 4, 5, 6, 7. As these detectors progress to even better sensitivity, they will encounter measurement limits imposed by the laws of quantum mechanics. If the imprecision of a measurement of the displacement of an oscillator8 is pushed below a scale set by the standard quantum limit, the measurement must perturb the motion of the oscillator by an amount larger than that scale. Here we show a displacement measurement with an imprecision below the standard quantum limit scale. We achieve this imprecision by measuring the motion of a nanomechanical oscillator with a nearly shot-noise limited microwave interferometer9. As the interferometer is naturally operated at cryogenic temperatures, the thermal motion of the oscillator is minimized, yielding an excellent force detector with a sensitivity of 0.51 aN Hz-1/2. This measurement is a critical step towards observing quantum be! haviour in a mechanical object. - Single-crystalline kinked semiconductor nanowire superstructures
Tian B Xie P Kempa TJ Bell DC Lieber CM - Nature nanotechnology 4(12):824-829 (2009)
The ability to control and modulate the composition1, 2, 3, 4, doping1, 3, 4, 5, crystal structure6, 7, 8 and morphology9, 10 of semiconductor nanowires during the synthesis process has allowed researchers to explore various applications of nanowires11, 12, 13, 14, 15. However, despite advances in nanowire synthesis, progress towards the ab initio design and growth of hierarchical nanostructures has been limited. Here, we demonstrate a 'nanotectonic' approach that provides iterative control over the nucleation and growth of nanowires, and use it to grow kinked or zigzag nanowires in which the straight sections are separated by triangular joints. Moreover, the lengths of the straight sections can be controlled and the growth direction remains coherent along the nanowire. We also grow dopant-modulated structures in which specific device functions, including p–n diodes and field-effect transistors, can be precisely localized at the kinked junctions in the nanowires. - True solutions of single-walled carbon nanotubes for assembly into macroscopic materials
Davis VA Parra-Vasquez AN Green MJ Rai PK Behabtu N Prieto V Booker RD Schmidt J Kesselman E Zhou W Fan H Adams WW Hauge RH Fischer JE Cohen Y Talmon Y Smalley RE Pasquali M - Nature nanotechnology 4(12):830-834 (2009)
Translating the unique characteristics of individual single-walled carbon nanotubes into macroscopic materials such as fibres and sheets has been hindered by ineffective assembly. Fluid-phase assembly is particularly attractive, but the ability to dissolve nanotubes in solvents has eluded researchers for over a decade. Here, we show that single-walled nanotubes form true thermodynamic solutions in superacids, and report the full phase diagram, allowing the rational design of fluid-phase assembly processes. Single-walled nanotubes dissolve spontaneously in chlorosulphonic acid at weight concentrations of up to 0.5wt%, 1,000 times higher than previously reported in other acids. At higher concentrations, they form liquid-crystal phases that can be readily processed into fibres and sheets of controlled morphology. These results lay the foundation for bottom-up assembly of nanotubes and nanorods into functional materials. - Atomic-scale mapping of quantum dots formed by droplet epitaxy
Kumah DP Shusterman S Paltiel Y Yacoby Y Clarke R - Nature nanotechnology 4(12):835-838 (2009)
Quantum dots (QDs) have applications in optoelectronic devices1, 2, quantum information processing3, 4 and energy harvesting5, 6. Although the droplet epitaxy fabrication method7, 8, 9 allows for a wide range of material combinations to be used, little is known about the growth mechanisms involved10, 11. Here we apply direct X-ray methods12, 13, 14 to derive sub-ångström resolution maps of QDs crystallized from indium droplets exposed to antimony, as well as their interface with a GaAs (100) substrate. We find that the QDs form coherently15 and extend a few unit cells below the substrate surface. This facilitates a droplet–substrate exchange of atoms, resulting in core–shell structures that contain a surprisingly small amount of In. The work provides the first atomic-scale mapping of the interface between epitaxial QDs and a substrate, and establishes the usefulness of X-ray phasing techniques for this and similar systems. - Ultrafast graphene photodetector
Xia F Mueller T Lin YM Valdes-Garcia A Avouris P - Nature nanotechnology 4(12):839-843 (2009)
Graphene research so far has focused on electronic1, 2, 3, 4, 5, 6 rather than photonic applications, in spite of its impressive optical properties7, 8. These include its ability to absorb 2% of incident light over a broad wavelength range despite being just one atom thick7. Here, we demonstrate ultrafast transistor-based photodetectors made from single- and few-layer graphene. The photoresponse does not degrade for optical intensity modulations up to 40 GHz, and further analysis suggests that the intrinsic bandwidth may exceed 500 GHz. The generation and transport of photocarriers in graphene differ fundamentally from those in photodetectors made from conventional semiconductors as a result of the unique photonic and electronic properties of the graphene. This leads to a remarkably high bandwidth, zero source–drain bias and dark current operation, and good internal quantum efficiency. - Programming the detection limits of biosensors through controlled nanostructuring
Soleymani L Fang Z Sargent EH Kelley SO - Nature nanotechnology 4(12):844-848 (2009)
Advances in materials chemistry offer a range of nanostructured shapes and textures for building new biosensors1, 2, 3, 4, 5, 6, 7, 8, 9, 10. Previous reports have implied that controlling the properties of sensor substrates can improve detection sensitivities, but the evidence remains indirect11, 12, 13. Here we show that by nanostructuring the sensing electrodes, it is possible to create nucleic acid sensors that have a broad range of sensitivities and that are capable of rapid analysis. Only highly branched electrodes with fine structuring attained attomolar sensitivity. Nucleic acid probes immobilized on finely nanostructured electrodes appear more accessible and therefore complex more rapidly with target molecules in solution. By forming arrays of microelectrodes with different degrees of nanostructuring, we expanded the dynamic range of a sensor system from two to six orders of magnitude. The demonstration of an intimate link between nanoscale sensor structure an! d biodetection sensitivity will aid the development of high performance diagnostic tools for biology and medicine. - Self-assembled arrays of peptide nanotubes by vapour deposition
Adler-Abramovich L Aronov D Beker P Yevnin M Stempler S Buzhansky L Rosenman G Gazit E - Nature nanotechnology 4(12):849-854 (2009)
The use of bionanostructures in real-world applications will require precise control over biomolecular self-assembly and the ability to scale up production of these materials1. A significant challenge is to control the formation of large, homogeneous arrays of bionanostructures on macroscopic surfaces2, 3, 4. Previously, bionanostructure formation has been based on the spontaneous growth of heterogenic populations in bulk solution1. Here, we demonstrate the self-assembly of large arrays of aromatic peptide nanotubes using vapour deposition methods. This approach allows the length and density of the nanotubes to be fine-tuned by carefully controlling the supply of the building blocks from the gas phase. Furthermore, we show that the nanotube arrays can be used to develop high-surface-area electrodes for energy storage applications, highly hydrophobic self-cleaning surfaces and microfluidic chips. - In vivo magnetic enrichment and multiplex photoacoustic detection of circulating tumour cells
Galanzha EI Shashkov EV Kelly T Kim JW Yang L Zharov VP - Nature nanotechnology 4(12):855-860 (2009)
The spread of cancer cells between organs, a process known as metastasis, is the cause of most cancer deaths1, 2. Detecting circulating tumour cells—a common marker for the development of metastasis3, 4—is difficult because ex vivo methods are not sensitive enough owing to limited blood sample volume and in vivo diagnosis is time-consuming as large volumes of blood must be analysed5, 6, 7. Here, we show a way to magnetically capture circulating tumour cells in the bloodstream of mice followed by rapid photoacoustic detection. Magnetic nanoparticles, which were functionalized to target a receptor commonly found in breast cancer cells, bound and captured circulating tumour cells under a magnet. To improve detection sensitivity and specificity, gold-plated carbon nanotubes conjugated with folic acid were used as a second contrast agent for photoacoustic imaging. By integrating in vivo multiplex targeting, magnetic enrichment, signal amplification and multicolour recog! nition, our approach allows circulating tumour cells to be concentrated from a large volume of blood in the vessels of tumour-bearing mice, and this could have potential for the early diagnosis of cancer and the prevention of metastasis in humans. - Performance of monolayer graphene nanomechanical resonators with electrical readout
Chen C Rosenblatt S Bolotin KI Kalb W Kim P Kymissis I Stormer HL Heinz TF Hone J - Nature nanotechnology 4(12):861-867 (2009)
The enormous stiffness and low density of graphene make it an ideal material for nanoelectromechanical applications. Here, we demonstrate the fabrication and electrical readout of monolayer graphene resonators, and test their response to changes in mass and temperature. The devices show resonances in the megahertz range, and the strong dependence of resonant frequency on applied gate voltage can be fitted to a membrane model to yield the mass density and built-in strain of the graphene. Following the removal and addition of mass, changes in both density and strain are observed, indicating that adsorbates impart tension to the graphene. On cooling, the frequency increases, and the shift rate can be used to measure the unusual negative thermal expansion coefficient of graphene. The quality factor increases with decreasing temperature, reaching 1 104 at 5 K. By establishing many of the basic attributes of monolayer graphene resonators, the groundwork for applications of ! these devices, including high-sensitivity mass detectors, is put in place. - Deterministic control of ferroelastic switching in multiferroic materials
Balke N Choudhury S Jesse S Huijben M Chu YH Baddorf AP Chen LQ Ramesh R Kalinin SV - Nature nanotechnology 4(12):868-875 (2009)
Multiferroic materials showing coupled electric, magnetic and elastic orderings provide a platform to explore complexity and new paradigms for memory and logic devices. Until now, the deterministic control of non-ferroelectric order parameters in multiferroics has been elusive. Here, we demonstrate deterministic ferroelastic switching in rhombohedral BiFeO3 by domain nucleation with a scanning probe. We are able to select among final states that have the same electrostatic energy, but differ dramatically in elastic or magnetic order, by applying voltage to the probe while it is in lateral motion. We also demonstrate the controlled creation of a ferrotoroidal order parameter. The ability to control local elastic, magnetic and torroidal order parameters with an electric field will make it possible to probe local strain and magnetic ordering, and engineer various magnetoelectric, domain-wall-based and strain-coupled devices. - Nanoparticles can cause DNA damage across a cellular barrier
Bhabra G Sood A Fisher B Cartwright L Saunders M Evans WH Surprenant A Lopez-Castejon G Mann S Davis SA Hails LA Ingham E Verkade P Lane J Heesom K Newson R Case CP - Nature nanotechnology 4(12):876-883 (2009)
The increasing use of nanoparticles in medicine has raised concerns over their ability to gain access to privileged sites in the body. Here, we show that cobalt–chromium nanoparticles (29.5 6.3 nm in diameter) can damage human fibroblast cells across an intact cellular barrier without having to cross the barrier. The damage is mediated by a novel mechanism involving transmission of purine nucleotides (such as ATP) and intercellular signalling within the barrier through connexin gap junctions or hemichannels and pannexin channels. The outcome, which includes DNA damage without significant cell death, is different from that observed in cells subjected to direct exposure to nanoparticles. Our results suggest the importance of indirect effects when evaluating the safety of nanoparticles. The potential damage to tissues located behind cellular barriers needs to be considered when using nanoparticles for targeting diseased states. - Anticipating the perceived risk of nanotechnologies
Satterfield T Kandlikar M Beaudrie CE Conti J Harthorn BH - Nature nanotechnology 4(12):883 (2009)
Introduction ; published online: 20 September 2009; corrected online: 29 November 2009. In the version of this Article originally published, the data from ref. 50 used in the meta-analysis and plotted in Fig. 2 were incorrect because these data were subsequently corrected in ref. 51. This mistake does not change any of the conclusions of the paper. An error also occurred in plotting the data from ref. 40 in Fig. 2, but the correct data were used in the rest of the paper. Figure 2 (including caption) and the first two sentences of the paragraph beginning "In the nine surveys" on page 754 of this Article have been amended accordingly in the HTML and PDF versions of the Article.
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