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Nanotechnology Spotlight

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Showing Spotlights 745 - 752 of 2024 in category (newest first):


Dynamically controlling graphene's properties with engineered piezoelectricity

graphene_latticeOne of the greatest challenges in harnessing the power of nanotechnology is achieving dynamic control of mechanical, electronic, optical and chemical properties of nanoscale structures and devices. Dynamic control can be achieved through the use of piezoelectric materials. These are materials where applying a mechanical strain results in an electrical voltage or conversely, application of an electric field induces mechanical deformation. While piezoelectricity has mainly been shown for 3D bulk materials, the piezoelectric effect has also been demonstrated and exploited at the nanoscale. Researchers have now demonstrated through density functional theory calculations that piezoelectricity can be engineered into non-piezoelectric graphene by selective surface adsorption of atoms on only one side, which breaks inversion symmetry.

Posted: Mar 22nd, 2012

Ultrasensitive chemical nanocoax sensor based on carbon nanotubes

nanocoax_sensorVarious types of nanostructures are used in the development of nanosensors: nanoparticles, nanotubes, nanorods, two-dimensional materials like graphene, embedded nanostructures, porous silicon, and self-assembled materials. For instance, gas sensors often operate by detecting the subtle changes that deposited gas molecules make in the way electricity moves through a surface layer. Researchers have fabricated gas sensors based on carbon nanotube-based field effect transistors, which can detect electrical potential changes around them. While these and related sensing schemes can be all-electronic - i.e., not requiring optical readout - they all require sophisticated nanolithographic techniques to isolate, identify, and integrate electrical contact to the active nanosensor. Researchers have now presented a nanoscale 3D architecture that can afford highly sensitive, room temperature, rapid response, and all-electronic chemical detection.

Posted: Mar 21st, 2012

Explosibility of nanoparticles

explosionRecent studies have found that nanomaterials - in this case dusts and powders having nanosize particles - exhibit an explosion severity which is not disproportionate to micrometer-sized materials, but the likelihood of explosion is quite high due to very low ignition energies and temperatures. A recent review concludes that nanomaterials present a dust explosion hazard, with metallic nanoparticles being particularly reactive. Nanomaterials have been shown to display lower ignition energy and temperature requirements than larger particles. Due to this high sensitivity, explosion hazards may exist for many processes including, but not limited to, mixing, grinding, drilling, sanding, and cleaning.

Posted: Mar 20th, 2012

A precise nanothermometer for intracellular temperature mapping

axonsGreen Fluorescent Protein (GFP) - originally found in a jellyfish - has played a crucial role in life science research, providing insights to many fundamental questions that have paved the way to the biology and medicine of the future. Since the mid-1990s, when the protein was successfully cloned, GFP can be found in research laboratories worldwide used as a visual marker of gene expression and protein localization, easily observed via light (optical) microscopy. GFP can be linked to other proteins and is primarily used to track dynamic changes in living cells. In 2008, biologists who discovered and developed the protein as a laboratory tool won a Nobel Prize for their work. Researchers in Spain have now demonstrated how GFP can also act as an efficient nano-thermometer inside cells.

Posted: Mar 19th, 2012

Nanotechnology Braille display could make Web accessible to the blind

Braille If you are a blind computer user you have to rely on electronic Braille displays which typically allow you to see only one line at a time, no matter what you were doing. Such a Braille display is a tactile, electro-mechanical device for displaying Braille characters, consisting of a row of special 'soft' cells. A soft cell has 6 or 8 pins made of metal or nylon; pins are controlled electronically to move up and down to display characters as they appear on the computer display. A number of cells are placed next to each other to form a soft or refreshable braille line. As the little pins of each cell pop up and down they form a line of braille text that can be read by touch. Researchers have now have fabricated a Braille sheet display by integrating organic thin-film transistor drivers, organic static random-access memory, and carbon nanotube-based actuators.

Posted: Mar 16th, 2012

New secrets of spider silk - its high thermal conductivity beats most materials

spiderResearchers and material scientists have been fascinated by spider silks for a long time - ultra-strong and extensible self-assembling biopolymers that outperform the mechanical characteristics of many synthetic materials, including steel. Atomistic studies have contributed to a better understanding of the source of the strength and toughness of this amazing biological material. Now, researchers have come up with another set of very surprising findings: The highly periodical structure of spider silk can sustain super fast thermal transport that surpasses those of most organic and inorganic materials. This discovery shows that highly organized organic materials can feature extremely high thermal conductivity.

Posted: Mar 15th, 2012

DNA reference tags allow single-molecule research on complex genomes

tagged_DNAKnowing the distribution of DNA binding proteins along the genome is very informative and can tell scientists about the state of gene expression at the time of measurement. These DNA-binding proteins include transcription factors which modulate the process of transcription, various polymerases, nucleases which cleave DNA molecules, and histones which are involved in chromosome packaging in the cell nucleus. Previously, researchers demonstrated the viability of a single-molecule approach to directly visualize and map protein binding sites on DNA using fluorescent quantum dots, allowing multicolor, nanometer-resolution localization. Now, they have shown that proteins bound to DNA can be located very accurately by direct imaging. The precision of these measurement presents new opportunities for contextual genomic research on the single-molecule level.

Posted: Mar 12th, 2012

Nanobrick walls make excellent gas barriers and flame retardants

flamesPolyurethane (PU) foam is an extremely versatile material that commonly is used in bedding, upholstery and building insulation. However, PU foam is very flammable, often resulting in dripping of melted material that enhances flame spread through the formation of a pool fire under the burning object. Brominated flame retardant compounds (e.g. pentabromodiphenyl ether) have been used to reduce foam flammability but there is growing evidence that these chemicals are toxic to the environment and living organisms. Replacing brominated flame retardants in polymer formulations with safer and more environmentally-friendly alternatives has also sparked the interest of nanoscientists. One recent effort to create an environmentally-friendly flame retardant system involves the layer-by-layer assembly of thin films using materials obtained from completely renewable sources.

Posted: Mar 9th, 2012