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Nanotechnology Spotlight – Latest Articles

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Showing Spotlights 1169 - 1176 of 2140 in category (newest first):

 

Microbots transport, assemble and deliver micro- and nanoscale objects

microfactorySophisticated molecular-size motors have evolved in nature, where they are used in virtually every important biological process. Some fascinating examples in nature are DNA and RNA polymerase, rotary motors such as ATP synthase, and flagella motors. In contrast, the development of synthetic nanomotors that mimic the function of these amazing natural systems and could be used in man-made nanodevices is in its infancy. Nevertheless, scientists are making good progress in achieving cargo transport by artificial nanomachines although often these advances are handicapped by several drawbacks. Researchers in Germany have now demonstrated the directed loading and transport of microobjects by high propulsion powered tubular microbots driven by a microbubble propulsion mechanism.

Aug 3rd, 2010

Novel electrical confinement method fabricates uniform quantum dots based on quantum well

nanoholeQuantum dots have been receiving extensive attention from researchers because they can be widely used for basic physics study, quantum computing, biological imaging, nanoelectronics, and photonics applications. Current major fabrication methods for semiconductor quantum dots all have certain drawbacks. Comparing all these methods, the electrical depletion method has many advantages, such as electrical tunability by gate contacts, smooth confinement boundaries, good control and uniformity if the top gate patterns are uniform enough. Researchers have now, for the first time, applied the electrical depletion method to quantum wells and generate a large area of uniform quantum dots using a uniform metallic nanoholes array on top of quantum wells. This design for forming quantum dots has inherited all the advantages of the electrical depletion method. Furthermore, it can produce millions of uniform quantum dots easily, precisely, and controllably, which will help realize the wide applications of quantum dots in many areas.

Jul 30th, 2010

Novel buckypaper device converts light into electricity

Previous studies have revealed that single-walled carbon nanotubes (SWCNTs) strongly absorb light, especially in the near-infrared region, and convert it into heat. There even has been a report that fluffy SWCNTs can burst into flames when exposed to a camera flash, which means the local temperature has reached 600-700C. This effect has already been used to develop effective CNT-based cancer killers or extremely dark materials. In a new twist, researchers in China have now discovered that SWCNT buckypapers have a large Seebeck coefficient, indicating a strong capability to convert heat into electricity. Based on this, they have designed an opto-electronic power source which converts the incident light into electricity. While this has been discussed as a theoretical mechanism, the team at Tsinghua University in Beijing has actually fabricated an integrated device that outputs a macroscopic voltage, moving forward towards practical applications.

Jul 29th, 2010

'Smart' sand: grain-sized nanotechnology electronic noses are on the horizon

sensor_nanostructureImagine a device the size of - and nearly as cheap as - a grain of sand which is capable of analyzing the environment around it, recognize its chemical composition, and report it to a monitoring system. This is the concept of nanotechnology-based electronic noses (e-nose) - miniature electronic devices which mimic the olfactory systems of mammals and insects and which will lead to better, cheaper and smaller sensor devices. An international team of researchers has made a further step towards this vision and demonstrated a novel analytical sensor which mimics our olfaction system. The difference between this and similar prior e-noses is that the active element of this new device is an individual wedge-like nanowire (nanobelt) made of tin dioxide. The required diversity of the sensing elements is encoded in the nanobelt morphology via longitudinal width variations of the nanobelt realized during its growth and via functionalization of some of the segments with palladium catalyst.

Jul 28th, 2010

Nanomagnets remove pathogens from blood

blood_cellsNumerous pathogens can cause bloodstream infections (sepsis) and the most straightforward cure is to remove the disease-causing factors from a patient's blood as quickly as possible. Several methods, like dialysis and plasma filtration/exchange, are already widely and routinely applied for this purpose. Demonstrating a novel use of nanomagnets, researchers in Switzerland have rapidly and selectively removed heavy metal ions, overdosed steroid drugs and proteins from human blood. This nanomagnet-based purification method avoids fouling of filter membranes and benefits from a high external surface area, and a correspondingly fast diffusion. Toxins or pathogens can be selectively removed from whole blood within minutes.

Jul 27th, 2010

Stakeholder preferences in regulating nanotechnology

law_booksHow to regulate nanotechnology and the application of nanomaterials has been quite a controversial issue in recent years. While for instance non-governmental organizations (NGOs) like Greenpeace and Friends of the Earth consider the existing regulatory situation to be inadequate and are urging a strictly precautionary approach, industry representatives are instead seeking the development of specific guidance and standards to support implementation of existing regulations, which are generally seen as adequate. Researchers have used Multicriteria Mapping (MCM) to study why some regulatory options - bans, moratoriums, voluntary measures, etc. - are deemed to be acceptable/unacceptable by various stakeholders in the U.S. and the criteria they use to evaluate the different regulatory options. Not surprisingly, the largest difference in ranking of the policy options can be observed between environmental NGOs and the representatives from the industrial companies and the trade association.

Jul 26th, 2010

Harmless natural nanoparticles show potential to replace metal-based nanoparticles in sunscreen

ivy_nanoparticlesQuite a lot of nanotechnology research and manufacturing efforts go into synthesizing metal-based nanoparticles. Unfortunately, some of the nanoparticle manufacturing processes themselves as well as the final nanoparticle materials may be of potential concern for environmental regulators and for researchers attempting to address nanomaterial toxicity. As an alternative to using these potentially hazardous metal-based nanoparticles, some researchers are suggesting the use of naturally occurring nanoparticles. However, this area has not yet been well explored with regard to natural nanoparticles' diverse properties and potential applications. Researchers have now made the discovery that naturally occurring nanoparticles have unique optical properties. In addition, they are less toxic and biodegradable than their synthesized, metal-based counterparts. This discovery makes it likely that scientists will be able to find more biocompatible nanoparticles to replace metal-based nanoparticles, predominantly for biomedical applications.

Jul 21st, 2010

New solar-powered process removes carbon dioxide from the air and stores it as solid carbon

air_pollutionThe alarming rise of carbon dioxide in the atmosphere has led a numerous proposals on how to capture and store carbon dioxide in order to mitigate the damaging emissions from fossil fuels. Popular proposals, some already being tested on a large scale, involve carbon sequestration and subsequent storage in geological formations (geo-sequestration). Other ideas revolve around recycling captured carbon dioxide, for instance by converting it into hydrocarbons that can be re-used to make fuel or plastics. While these solutions would result in removing some carbon dioxide from the atmosphere, their disadvantages are that most of them are expensive, technologically challenging, or energy-intensive. Researchers have now presented the first experimental evidence of a new solar conversion process, combining electronic and chemical pathways, for carbon dioxide capture in what could become a revolutionary approach to remove and recycle CO2 from the atmosphere on a large scale. Rather than trying to sequester or hide away excess carbon dioxide, this new method allows it to be stored as solid carbon or converted in useful products.

Jul 16th, 2010