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Nanotechnology Spotlight

Behind the buzz and beyond the hype:
Our Nanowerk-exclusive feature articles

Showing Spotlights 1441 - 1448 of 1602 in category All (newest first):

 

Sulfur as a promoter for growing intrinsic functional carbon nanotube elements

Individual carbon nanotubes (CNTs) of different structural and thus electronic characteristics can be joined to build up three-terminal logic devices. However, today this can only be achieved using highly sophisticated nanomanipulation processes. The direct growth of intrinsic functional CNT elements such as Y-shaped CNTS (YCNTs) and helical CNTs (HCNTs) can be considered as an important alternative. YCNTs already have proven to show rapid and nonlinear transistor action without the need for external gating, while HCNTs could be used as inductive elements offering rapid signal processing. Additionally, HCNTs have shown operational functionality as high sensitivity force and mass sensors and are of great interest for nanoelectromechanical systems (NEMS). A research group in Spain now reports that sulfur may be used as a highly efficient additive in chemical vapor deposition (CVD) processes, allowing enhanced selectivity in the synthesis of helical and Y-shaped CNTs.

Posted: Sep 29th, 2006

Nanoscale prisons lock up molecules

Imagine to catch one, or a few, molecules dissolved in water, lock them up in a cage with a diameter of a few hundred nanometers, and keep them locked for a given length of time. Then bring these containers with the "captive" molecules to places within the solution where you want to have them, and release the captured molecules from their captivity on chemical command. Or simply keep the molecules in the cage "prison" locked up, add a few more different molecules to water, and watch their chemical reaction following movement across the container wall in "solitary" confinement within the containers with the molecules already captured. Such dreams of nanotechnologists have come much closer to reality as a result of a discovery made by a team of researchers, lead by Professor Julius Vancso of the University of Twente, from the MESA+ Institute for Nanotechnology collaborating with scientists of the Max Planck Institute of Colloids and Interfaces in Golm, Germany.

Posted: Sep 28th, 2006

Flipping the spin...

Spintronics (short for "spin-based electronics") is an emergent technology which exploits the quantum propensity of electrons to spin as well as making use of their charge state. The spin itself is manifested as a detectable weak magnetic energy state characterized as "spin up" and "spin down". Spin flip length is an important parameter to know for designing spintronics devices. Because in spintronics, electron spin carries the information, it is important to know how far electrons can travel in a device before this spin information is lost. In a discovery that could contribute to the emerging field of spintronics, scientists at Oak Ridge National Laboratory (ORNL) and the Institute of Physics, Chinese Academy of Science, have demonstrated a way to measure the distance an electron travels in nanoscale materials before its spin is reversed due to scattering.

Posted: Sep 27th, 2006

Carbon nanotube forests as non-stick workbenches

The ubiquitous static friction (stiction) and adhesion forces comprise a major obstacle in the manipulation of matter at the nanoscale. In order to realize the potential of nanotubes and nanowires as components in electronic devices or other microsystems, methods for reliable pick-and-place assembly must be established. A major obstacle here is the delicate balance required between the adhesion forces acting between the object to be manipulated, and the surface and the manipulation tool, respectively. A group od Danish and UK researchers found that self-assembled organic nanofibers, which are otherwise totally impossible to remove from any normal surface, can be lifted straight off from a nanotube forest. It means that the notorious stickiness of even the most soft and fragile materials, which immobilizes them and prevent handling, is a problem that now can be solved.

Posted: Sep 26th, 2006

Stealth nanoparticles for long term in vivo drug treatment

Phagocytosis is a cellular phenomena that describes the process in which phagocytes (specialized cells such as macrophages) destroy viruses and foreign particles in blood. Phagocytes are an important part of the immune system. Unfortunately, phagocytes are also a major limitation for the intravenous delivery of polymeric nanoparticles. The use of such nanoparticles to deliver therapeutic agents is currently being studied as a promising method by which drugs can be effectively targeted to specific cells in the body, such as cancerous cells. Researchers at Penn State are trying to trick the body's immune system, and increase the circulation time of nano drug carriers in the blood, with stealth drug nanoparticles that could be fabricated by self-assembling a shell on the surface of a solid drug core. This research could lead to the possibility of long term drug treatment in vivo.

Posted: Sep 25th, 2006

Pros and cons of biodegradable nanoparticle drug delivery systems to the lung

Particulate nanocarriers have been praised for their advantageous drug delivery properties in the lung, such as avoidance of macrophage clearance mechanisms and long residence times. However, instilled non-biodegradable polystyrene nanospheres with small diameters and thus large surface areas have been shown to induce pulmonary inflammation. New evidence suggests that biodegradable polymeric nanoparticles designed for pulmonary drug delivery may not induce the same inflammatory response as non-biodegradable polystyrene particles of comparable size.

Posted: Sep 22nd, 2006

Butterflies provide clues for replacing color pigments with photonic nanocrystals

Photonic crystals are attractive optical materials for controlling and manipulating the flow of light. They can be engineered to produce a variety of optical filtering functions. The growing efforts of physicists and materials scientists to fabricate photonic (nano)crystals were motivated mainly by the potential application of these materials in optical computing, the manufacturing of more efficient lasers, and other exciting new phenomena, like those arising from the application of disturbances such as shock waves. The manufacturing of large-area photonic crystals operating in the visible spectrum is still a challenging and expensive task, given present-day laboratory techniques. However, as with so many other materials, nature has already found a solution. Because they are ready made, common in nature, and because they show a very high complexity, biological photonic-crystal structures will be an essential tool for building a useful knowledge of inhomogeneous optical media.

Posted: Sep 21st, 2006

The promise of biomolecular motors

In the field of Nanotechnology, where inherent risks are the subject of hot debate, developments within the nascent science of biomolecular motors is hailed by scientists to be relatively benign to humans and possibly beneficial to the environment (even for applications within the military). Biomolecular motors are currently an area of fundamental research, with working applications years in the future. Biological organisms on the micro and nano scales have always used the mechanism of converting ATP (Adenosine Tri-Phosphate - the universal fuel molecule that powers all cells) into mechanical energy. Therefore an existence proof that this concept could fare very well has existed for millennia. Today's question is: "how to manufacture engineering devices powered by ATP?"

Posted: Sep 20th, 2006