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Nanotechnology Spotlight

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

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Showing Spotlights 1505 - 1512 of 1663 in category All (newest first):

 

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

Gaining a better understanding of fullerene growth mechanisms - one carbon molecule at a time

With a better understanding of how fullerenes and nanotubes form, scientists and material engineers would be in a better position to provide conditions more favorable for the formation of a particular fullerene or a particular chirality and length nanotube. Researchers have used a number of computational and theoretical tools to explain the experimental observations and develop a picture of the dynamics for fullerene growth, yet no universally agreed model exists for the fullerene growth. To understand the phenomenon of fullerene growth during its synthesis, researchers modeled a minimum energy growth route using a semi-empirical quantum mechanics code. C2 addition leading to C60 was modeled and three main routes, i.e. cyclic ring growth, pentagon and fullerene road, were studied.

Posted: Sep 19th, 2006

Biomechanical nanoswitches open door to green bioelectronics

The ability to generate functional nanoswitches might ultimately allow the integration of nano-components into electronic components. Single molecule switches using scanning tunneling microscope (STM) manipulation have been demonstrated before. Mostly these switches are based on single atoms or small molecules and operate between two distinct states. Researchers now realized the first multi-step switching process by STM manipulation on a single molecule. Instead of small organic molecules they used a large plant molecule which is environmentally friendly and abundant in nature.

Posted: Sep 18th, 2006

Manufacturing multifunctional materials by surface design at the nanoscale

New research coming out of France opens the route for the processing of numerous multifunctional materials with specific properties. So far, the design of new multifunctional devices based on the combination of different materials has been a real challenge in materials science. One way to develop multifunctional materials is the design of a surface at the nanometer scale. However, modifying the surface of materials by organizing nanoparticles of controlled size, morphology and amount of coverage into a uniform shell has proven to be a considerable hurdle. Numerous approaches are being developed for the synthesis of these materials using organic or inorganic coatings. French researchers used a coating process called supercritical fluid chemical deposition for nanomaterial surface design.

Posted: Sep 15th, 2006