Latest Articles Include:
- Nanofood for thought
- Nature nanotechnology 5(2):89 (2010)
The bone marrow could be considered to be the immune system's safe house — being a secure location, suitable for lying low and staying out of harms way. Indeed, haematopoietic stem cells (HSCs) can safely lie dormant in specialized bone marrow niches, being aroused from their slumber to replenish blood cells only in times of need. - Nanotechnology in fertilizers
Derosa MC Monreal C Schnitzer M Walsh R Sultan Y - Nature nanotechnology 5(2):91 (2010)
The food industry will only reap the benefits of nanotechnology if issues related to safety are addressed and companies are more open about what they are doing. - Nanomaterials and regulation of cosmetics
Bowman DM van Calster G Friedrichs S - Nature nanotechnology 5(2):92 (2010)
Nitrogen, which is a key nutrient source for food, biomass, and fibre production in agriculture, is by far the most important element in fertilizers when judged in terms of the energy required for its synthesis, tonnage used and monetary value. However, compared with amounts of nitrogen applied to soil, the nitrogen use efficiency (NUE) by crops is very low. - Reported nanosafety practices in research laboratories worldwide
Balas F Arruebo M Urrutia J Santamaria J - Nature nanotechnology 5(2):93-96 (2010)
In November 2009 the member states of the European Union (EU) agreed to recast some 55 directives relating to cosmetics into a single regulation on cosmetic products1 that is intended, among other things, to streamline human safety requirements and increase transparency. The adoption of this regulation is significant, not least because it is the first piece of national or supranational legislation to incorporate rules relating specifically to the use of nanomaterials in any products. - Our choice from the recent literature
- Nature nanotechnology 5(2):97 (2010)
An online survey shows that most researchers do not use suitable personal and laboratory protection equipment when handling nanomaterials that could become airborne. - Single-molecule detection: Focusing on the objective
Ebenstein Y Bentolila LA - Nature nanotechnology 5(2):99-100 (2010)
Molecular transistors: Another gate opens Nanoparticle catalysts: Two-faced Carbon nanotubes: Prodigious pores Self-assembly: Recipe for antibodies - Nanoelectronics: Single dopants learn their place
Rogge S - Nature nanotechnology 5(2):100-101 (2010)
From the following article Reported nanosafety practices in research laboratories worldwide Francisco Balas, Manuel Arruebo, Jone Urrutia & Jesus Santamaria Nature Nanotechnology 5, 93 - 96 (2010) Published online: 31 January 2010 doi:10.1038/nnano.2010.1 BACK TO ARTICLE Download plugins and applications Supplementary information Supplementary information Supplementary information - Download PDF file (431 KB) BACK TO ARTICLE DOWNLOAD PLUGINS FOR YOUR BROWSER Movie files * QuickTime Player (PC or Mac) * Realplayer (PC or Mac) * Windows Media player (PC only) PDF douments * Adobe Acrobat Reader (PC or Mac) Text documents * Textpad (PC only) * SimpleText (Mac only) PostScript documents * GhostView (Mac and PC) Flash movies * Macromedia Flash Player Audio files * Apple iTunes (PC or Mac) * QuickTime Player (PC or Mac) * Realplayer (PC or Mac) * Windows Media player (PC only) Chemical structures * MDL Chime Microarray * Treeview Compressed Stuff files * StuffIt Expander Compressed Zip files * WinZip (PC only) Systems Biology Markup Language files (SBML) * More information about SMBL Chemical Markup language files (CML) * More information about CML BACK TO ARTICLE - Probe microscopy: Images from below the surface
Garcia R - Nature nanotechnology 5(2):101-102 (2010)
Placing colloidal spheres in the immediate proximity of fluorescent molecules makes it possible to achieve single-molecule imaging at high temperatures with a low-cost system. - Carbon nanotubes: Growth potential
Bodwell GJ - Nature nanotechnology 5(2):103-104 (2010)
The presence of just one dopant atom can dramatically alter the performance of a short-channel transistor, depending on where it is located. - New modes for subsurface atomic force microscopy through nanomechanical coupling
Tetard L Passian A Thundat T - Nature nanotechnology 5(2):105-109 (2010)
An atomic force microscope can reveal a range of subsurface information about a sample through mechanical excitation of both the sample and the tip. - Highly conductive self-assembled nanoribbons of coordination polymers
Welte L Calzolari A Di Felice R Zamora F Gómez-Herrero J - Nature nanotechnology 5(2):110-115 (2010)
Could carbon nanotubes of a single chirality be grown from the bottom up using a common organic reaction? - Switching binary states of nanoparticle superlattices and dimer clusters by DNA strands
Maye MM Kumara MT Nykypanchuk D Sherman WB Gang O - Nature nanotechnology 5(2):116-120 (2010)
Non-destructive, nanoscale characterization techniques are needed to understand both synthetic and biological materials. The atomic force microscope uses a force-sensing cantilever with a sharp tip to measure the topography and other properties of surfaces1, 2. As the tip is scanned over the surface it experiences attractive and repulsive forces that depend on the chemical and mechanical properties of the sample. Here we show that an atomic force microscope can obtain a range of surface and subsurface information by making use of the nonlinear nanomechanical coupling between the probe and the sample. This technique, which is called mode-synthesizing atomic force microscopy, relies on multi-harmonic forcing of the sample and the probe. A rich spectrum of first- and higher-order couplings is discovered, providing a multitude of new operational modes for force microscopy, and the capabilities of the technique are demonstrated by examining nanofabricated samples and plant ! cells3, 4. - Large-area spatially ordered arrays of gold nanoparticles directed by lithographically confined DNA origami
Hung AM Micheel CM Bozano LD Osterbur LW Wallraff GM Cha JN - Nature nanotechnology 5(2):121-126 (2010)
Nanoscale components can be self-assembled into static three-dimensional structures1, 2, 3, 4, 5, 6, arrays7, 8, 9 and clusters10, 11, 12, 13 using biomolecular motifs. The structural plasticity of biomolecules and the reversibility of their interactions can also be used to make nanostructures that are dynamic, reconfigurable and responsive. DNA has emerged as an ideal biomolecular motif for making such nanostructures, partly because its versatile morphology permits in situ conformational changes using molecular stimuli12, 14, 15, 16, 17, 18, 19, 20, 21, 22. This has allowed DNA nanostructures to exhibit reconfigurable topologies and mechanical movement17, 18. Recently, researchers have begun to translate this approach to nanoparticle interfaces18, 23, 24, where, for example, the distances between nanoparticles can be modulated, resulting in a distance-dependent plasmonic response18, 23, 25. Here, we report the assembly of nanoparticles into three-dimensional superlatt! ices and dimer clusters, using a reconfigurable DNA device that acts as an interparticle linkage. The interparticle distances in the superlattices and clusters can be modified, while preserving structural integrity, by adding molecular stimuli (simple DNA strands) after the self-assembly processes has been completed. Both systems were found to switch between two distinct rigid states, but a transition to a flexible device configuration within a superlattice showed a significant hysteresis. - Colloidal lenses allow high-temperature single-molecule imaging and improve fluorophore photostability
Schwartz JJ Stavrakis S Quake SR - Nature nanotechnology 5(2):127-132 (2010)
The development of nanoscale electronic and photonic devices will require a combination of the high throughput of lithographic patterning and the high resolution and chemical precision afforded by self-assembly1, 2, 3, 4. However, the incorporation of nanomaterials with dimensions of less than 10 nm into functional devices has been hindered by the disparity between their size and the 100 nm feature sizes that can be routinely generated by lithography. Biomolecules offer a bridge between the two size regimes, with sub-10 nm dimensions, synthetic flexibility and a capability for self-recognition. Here, we report the directed assembly of 5-nm gold particles into large-area, spatially ordered, two-dimensional arrays through the site-selective deposition of mesoscopic DNA origami5 onto lithographically patterned substrates6 and the precise binding of gold nanocrystals to each DNA structure. We show organization with registry both within an individual DNA template and betwee! n components on neighbouring DNA origami, expanding the generality of this method towards many types of patterns and sizes. - Single-donor ionization energies in a nanoscale CMOS channel
Pierre M Wacquez R Jehl X Sanquer M Vinet M Cueto O - Nature nanotechnology 5(2):133-137 (2010)
Although single-molecule fluorescence spectroscopy was first demonstrated at near-absolute zero temperatures (1.8 K)1, the field has since advanced to include room-temperature observations2, largely owing to the use of objective lenses with high numerical aperture, brighter fluorophores and more sensitive detectors. This has opened the door for many chemical and biological systems to be studied at native temperatures at the single-molecule level both in vitro3, 4 and in vivo5, 6. However, it is difficult to study systems and phenomena at temperatures above 37 °C, because the index-matching fluids used with high-numerical-aperture objective lenses can conduct heat from the sample to the lens, and sustained exposure to high temperatures can cause the lens to fail. Here, we report that TiO2 colloids with diameters of 2 µm and a high refractive index can act as lenses that are capable of single-molecule imaging at 70 °C when placed in immediate proximity to an emitting ! molecule. The optical system is completed by a low-numerical-aperture optic that can have a long working distance and an air interface, which allows the sample to be independently heated. Colloidal lenses were used for parallel imaging of surface-immobilized single fluorophores and for real-time single-molecule measurements of mesophilic and thermophilic enzymes at 70 °C. Fluorophores in close proximity to TiO2 also showed a 40% increase in photostability due to a reduction of the excited-state lifetime. - Label-free biomarker detection from whole blood
Stern E Vacic A Rajan NK Criscione JM Park J Ilic BR Mooney DJ Reed MA Fahmy TM - Nature nanotechnology 5(2):138-142 (2010)
One consequence of the continued downward scaling of transistors is the reliance on only a few discrete atoms to dope the channel, and random fluctuations in the number of these dopants are already a major issue in the microelectronics industry1. Although single dopant signatures have been observed at low temperatures2, 3, 4, 5, 6, 7, 8, the impact on transistor performance of a single dopant atom at room temperature is not well understood. Here, we show that a single arsenic dopant atom dramatically affects the off-state room-temperature behaviour of a short-channel field-effect transistor fabricated with standard microelectronics processes. The ionization energy of the dopant is measured to be much larger than it is in bulk, due to its proximity to the buried oxide9, 10, and this explains the large current below threshold and large variability in ultra-scaled transistors. The results also suggest a path to incorporating quantum functionalities into silicon CMOS devic! es through manipulation of single donor orbitals. - Above-bandgap voltages from ferroelectric photovoltaic devices
Yang SY Seidel J Byrnes SJ Shafer P Yang CH Rossell MD Yu P Chu YH Scott JF Ager JW Martin LW Ramesh R - Nature nanotechnology 5(2):143-147 (2010)
Label-free nanosensors can detect disease markers to provide point-of-care diagnosis that is low-cost, rapid, specific and sensitive1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13. However, detecting these biomarkers in physiological fluid samples is difficult because of problems such as biofouling and non-specific binding, and the resulting need to use purified buffers greatly reduces the clinical relevance of these sensors. Here, we overcome this limitation by using distinct components within the sensor to perform purification and detection. A microfluidic purification chip simultaneously captures multiple biomarkers from blood samples and releases them, after washing, into purified buffer for sensing by a silicon nanoribbon detector. This two-stage approach isolates the detector from the complex environment of whole blood, and reduces its minimum required sensitivity by effectively pre-concentrating the biomarkers. We show specific and quantitative detection of two model ! cancer antigens from a 10 µl sample of whole blood in less than 20 min. This study marks the first use of label-free nanosensors with physiological solutions, positioning this technology for rapid translation to clinical settings. - Atomic structure of conducting nanofilaments in TiO2 resistive switching memory
Kwon DH Kim KM Jang JH Jeon JM Lee MH Kim GH Li XS Park GS Lee B Han S Kim M Hwang CS - Nature nanotechnology 5(2):148-153 (2010)
In conventional solid-state photovoltaics, electron–hole pairs are created by light absorption in a semiconductor and separated by the electric field spaning a micrometre-thick depletion region. The maximum voltage these devices can produce is equal to the semiconductor electronic bandgap. Here, we report the discovery of a fundamentally different mechanism for photovoltaic charge separation, which operates over a distance of 1–2 nm and produces voltages that are significantly higher than the bandgap. The separation happens at previously unobserved nanoscale steps of the electrostatic potential that naturally occur at ferroelectric domain walls in the complex oxide BiFeO3. Electric-field control over domain structure allows the photovoltaic effect to be reversed in polarity or turned off. This new degree of control, and the high voltages produced, may find application in optoelectronic devices. - Electrically controlled DNA adhesion
Erdmann M David R Fornof A Gaub HE - Nature nanotechnology 5(2):154-159 (2010)
Resistance switching in metal oxides could form the basis for next-generation non-volatile memory. It has been argued that the current in the high-conductivity state of several technologically relevant oxide materials flows through localized filaments, but these filaments have been characterized only indirectly, limiting our understanding of the switching mechanism. Here, we use high-resolution transmission electron microscopy to probe directly the nanofilaments in a Pt/TiO2/Pt system during resistive switching. In situ current–voltage and low-temperature (~130 K) conductivity measurements confirm that switching occurs by the formation and disruption of TinO2n−1 (or so-called Magnéli phase) filaments. Knowledge of the composition, structure and dimensions of these filaments will provide a foundation for unravelling the full mechanism of resistance switching in oxide thin films, and help guide research into the stability and scalability of such films for applicatio! ns. - Electrostatic focusing of unlabelled DNA into nanoscale pores using a salt gradient
Wanunu M Morrison W Rabin Y Grosberg AY Meller A - Nature nanotechnology 5(2):160-165 (2010)
The ability to control the interaction of polyelectrolytes, such as DNA or proteins, with charged surfaces is of pivotal importance for a multitude of biotechnological applications. Previously, we measured the desorption forces of single polymers on charged surfaces using an atomic force microscope. Here, we show that the adhesion of DNA on gold electrodes modified with self-assembled monolayers can be biased by the composition of the monolayer and externally controlled by means of the electrode potential. Positive potentials induced DNA adsorption onto OH-terminated electrodes with adhesion forces up to 25 pN (at +0.5 V versus Ag/AgCl), whereas negative potentials suppressed DNA adsorption. The measured contributions of the DNA backbone phosphate charges and the doubly charged terminal phosphate on adsorption agreed with a model based on the Gouy–Chapman theory. Experiments on an NH2-terminated electrode revealed a similar force modulation range of the coulomb compo! nent of the desorption force. These findings are important for the development of new DNA-based biochips or supramolecular structures.
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