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Nanotechnology Spotlight

Behind the buzz and beyond the hype:
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Showing Spotlights 1521 - 1528 of 1662 in category All (newest first):

 

DNA as template for assembling nanostructures

Recent developments in DNA-based nanotechnology have shown the suitability of this novel assembly method for constructing useful nanostructures. DNA molecules can serve as precisely controllable and programmable scaffolds for organizing functional nanomaterials in the design, fabrication, and characterization of nanometer scale electronic devices and sensors. DNA-templated metallic nanowires are such an example and over the past few years DNA scaffolds have been metallized with silver, gold, palladium, platinum and copper. DNA-based fabrication methods could ultimately lead to naturally bio-compatible nanodevices.

Posted: Aug 31st, 2006

The flip side of using carbon nanotubes for environmental pollutants removal

Carbon nanomaterials have been studied as superior sorbents for their potential environmental applications to remove pollutants such as organic pollutants, metals, fluorides and radionuclides. Most of these studies focused on the adsorption process and few dealt with the interfacial interactions of organic contaminants with carbon nanomaterials in aqueous media. However, understanding their desorption behavior as well is critical to evaluating environmental and health impacts of carbon nanomaterials. New research looks at the high adsorption capacity and reversible adsorption of PAHs (polycyclic aromatic hydrocarbons), many of which are suspected carcinogens, on CNTs. The findings imply the potential release of PAHs if PAH-adsorbed CNTs are inhaled by animals and humans, leading to a high environmental and public health risk.

Posted: Aug 30th, 2006

Numbering up: The use of microreactors for nanomanufacturing

Microscale reactor technology has tremendous advantage over conventional macro-scale or batch chemical processes, and offers versatility for a wide range of applications including chemical analyses, drug discovery, radiotracer synthesis, and the fabrication of engineered nanomaterials. Attention is currently focused on developing scaleable process regimes, using an approach engineers call numbering up. Microreactor technology is defined by a series of interconnected, functionally distinct channels formed on a planar surface, utilizing either hydrodynamic or (EOF) for pumping, with channel dimensions typically between 10-300 microns.

Posted: Aug 29th, 2006

Infrared imaging of sub-10 nm particles

Objects a thousand times smaller than the wavelength of infrared light (10 micrometers) are undetectable by standard far-field optical infrared microscopy since the weak nanoparticle signals would be buried far below the background level. To overcome this drawback and to achieve nanoscale spatial resolution researchers in Germany illuminate the nanoparticles by a highly intensive nanoscale infrared light spot. It is generated in the nano-gap between a laser-illuminated scanning metal tip and the substrate supporting the particles. The simple but very efficient trick finally allowing detection of sub-10 nm particles is the use of highly reflecting substrates instead of glass slides typically used as a sample carrier in optical microscopy.

Posted: Aug 28th, 2006

Template-free synthesis of hollow nanostructures

Among many nanomaterials with distinct geometric shapes, spheres and cubes are the two simplest forms, yet they possess the highest symmetries. One of the obvious geometric merits of this class of materials is their low resistivity under fluidic conditions, as they can be essentially considered as zero-dimensional entities when their size is trimmed down to the nanoscale regime. So far, most hollow interiors of nanomaterials are created by template-methods. Researchers in Singapore for the first time demonstrated that nanostructured polyhedrons of functional materials with desired interiors can be synthesized template-free through a simple hydrothermal method.

Posted: Aug 25th, 2006

Nanoscience and nanotechnology in Latin America

The year 2005 was an important year for nanoscience and nanotechnology in Latin America. Brazil increased federal funding for its nanotechnology program. In Mexico, the Senate Committee for Science and Technology declared itself in favor of the development of a National Emergency Program for investment in research and teaching of nanotechnology. In Colombia, the National Council of Nanoscience and Nanotechnology was created. But all this was not done without controversy; and it was in Argentina that conflicts in the scientific and political spheres were concentrated, with repercussions in the media. In Argentina, many of the things that took place in a short span of time might take longer than in many other Latin American countries.

Posted: Aug 24th, 2006

Amazing survivors: bacteria from radioactive wastes that produce precious metal nanoparticles

Some microbes are able to tolerate radioactivity and other toxic environments because they developed detoxification mechanisms that allow them to resist adverse environments without being damaged. These protective mechanisms increasingly are of great interest to scientists not only for developing innovative remediation strategies but also for creating novel biotechnological applications. As a recent example, researchers in Germany managed to produce highly stable and regular palladium (Pd) nanoparticles by harnessing the survival mechanism of bacteria found in uranium-polluted waste. These particles showed much improved catalytic activity and other new physical properties , which make them ideal for use as nanocatalysts or nanosensors.

Posted: Aug 23rd, 2006

Non-toxic nanolithography using pure water

Conventionally, the fabrication of thin film nanostructures is primarily done by using selective etching or templating growth on a prepatterned resist and then performing lift-off. The solvents used in developing resist are typically toxic and add to the cost of lithographic processing. Recently, many environmentally friendly lithographic processes have been designed using either a water-based solution or supercritical carbon dioxide to develop the resist. A novel pure water developable spin-coatable lanthanum strontium manganese oxide (LSMO) resist has been developed by scientists in Taiwan. The use of pure water instead of organic or alkaline solvents would undoubtedly be not only environmentally desirable but also could greatly simplify the imaging process.

Posted: Aug 22nd, 2006