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Power Walk This Way: Scientists Develop Device That Harnesses Energy from Everyday Movements

March 25, 2010 by · Leave a Comment 

Power Walk This Way: Scientists Develop Device That Harnesses Energy from Everyday Movements
(PhysOrg.com) — These boots are made for walking… and for powering up your cell phone? It could happen, say a team of Princeton and Caltech scientists. In a recent paper in the journal Nano Letters, they report that they have developed an innovative rubber chip that has the ability to harvest energy from motions such as walking, running, and breathing and convert it into a power source.

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Q&A: Henk Postma on Graphene Nanogaps for Electronic Single-Molecule Sequencing

March 22, 2010 by · Leave a Comment 

Q&A: Henk Postma on Graphene Nanogaps for Electronic Single-Molecule Sequencing
Earlier this year , Henk Postma, a nanotechnology researcher at California State University Northridge, published an article in Nano Letters in which he proposed to sequence DNA using graphene nanogaps.

Read more on GenomeWeb News

Longest Nanowires May Lead To Better Fuel Cells

March 3, 2010 by · Leave a Comment 

We are searching for the alternative energy which can conveniently be used for our industrial and everyday purposes. Wind, water, geothermal and many other alternative energy sources are good and clean and green. But all of them lack one thing or another and donâ??t seem commercially viable. Researchers all over the world are trying to find solutions for this impending and inevitable energy crisis. Scientists from University of Rochester are trying to do the same thing. They are aiming to produce longest platinum nanowires. This feat has not been achieved by anyone. These longest platinum nanowires could make an impact on the development of fuel cells for cars, trucks and other devices. The wires, 1/50,000 the width of a human hair, are thousands of times longer than any previously made, according to a report in Nano Letters.

James C. M. Li who is the professor of mechanical engineering at the University of Rochester, states, â??People have been working on developing fuel cells for decades. But the technology is still not being commercialized. Platinum is expensive, and the standard approach for using it in fuel cells is far from ideal. These nanowires are a key step toward better solutions.â?

These platinum nanowires are better for the longevity and efficiency of fuel cells. Till now these nanowires are utilized in the spacecrafts only. Now team of researchers at University of Rochester are of the view that platinum nanowires can be exploited as modes of transport fuel. â??Our ultimate purpose is to make free-standing fuel cell catalysts from these nanowires,â? says Li. This discovery would reduce the consumption of conventional fuels.

Fuel cells require catalysts that can facilitate the reaction of hydrogen and oxygen. This will split the compressed hydrogen fuel into acidic hydrogen ion and release the electrons. These electrons are diverted into an external circuit to provide energy. What happened to the hydrogen ions? Those hydrogen ions combine with electrons and oxygen to create the byproduct in the form of liquid or vaporous water.

Platinum has been the chief substance utilized as catalysts in making fuel cell because platinum has the ability to endure the harsh acidic environment inside the fuel cell. Platinumâ??s energy efficiency is also considerably greater than that of cheaper metals like nickel.

The efficiency of the catalysts in increased by maximizing the exposed surface area of platinum nanoparticles. The technology has already been used or nanocomputers and other nano devices. The big difference in the platinum nanowires produced by Li and his graduate student Jianglan Shui is that by a process known as electrospinning they have produced platinum nanowires that are thousands of times longer than any previous such wires.

Making such nanowires is a highly challenging task. â??The reason people have not come to nanowires before is that itâ??s very hard to make them,â? says Li. â??The parameters affecting the morphology of the wires are complex. And when they are not sufficiently long, they behave the same as nanoparticles.â?

The problem with previous technologies is that they heavily depend on nanoparticles in order to expose the surface area of platinum to the maximum. The more surface area there is, apparently the greater is the efficiency. But the basic problem is these particles can always merge through a process called surface diffusion, combining, and consequently reducing the total surface area and the amount of energy produced. The second problem is that nanoparticles need the carbon support structure to stop them from going haywire. Carbon is subject to oxidation, and these particles donâ??t go well with carbon structures. As the carbon degrades, the particles are permanently lost.

This doesnâ??t happen in the case of nanowires. Since platinum is uniformly arranged in a thin wire the particles comprising them do not need the carbon structures to support them.

Beads that would have formed on the platinum nanowires would have caused another problem and Liâ??s team has taken care of it. â??With platinum being so costly, itâ??s quite important that none of it goes to waste when making a fuel cell,â? says Li. â??We studied five variables that affect bead formation and we finally got itâ??nanowires that are almost bead free.â?

 

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Nanosys Announces Promising Results With Its Gecko-Inspired Drug Delivery Device

November 9, 2009 by · Leave a Comment 

Nanosys, Inc. announced today the results of their initial studies using a novel silicon nanowire mucous membrane drug delivery device. These devices have a nano-structured surface that relies on adhesive properties known in physics as van der Waals forces of adhesion. Results of initial studies published this week in the American Chemical Society’s Nano Letters, outline the device’s ability to significantly improve drug delivery to mucous membranes such as those in the nose, intestine, eyes, vagina and mouth.

Mucous membranes have long been a target for drug delivery due to their large surface area and rich blood supply. However, nature has designed these membranes to also be efficient barriers to foreign substance penetration, such as drugs. Mucus, which is constantly produced by these tissues, is moved across the surface by tiny beating hair-like structures called cilia. Removal of a substance floating in the mucus of the nasal cavity can be as fast as ten minutes, for example. Previous attempts at overcoming this barrier function relied on chemical modification of the delivery vehicle to better adhere to binding elements within the mucus. Nanosys’s silicon nanowires will adhere instead to the cells underneath the mucus, the actual targets for drug delivery. This critical feature allows for a longer residence time, improved local concentrations and better absorption of target drugs by the tissues.

The team, led by Hugh Daniels at Nanosys and Tejal Desai and Kayte Fischer at the University of California, San Francisco, also quantified the amount of mucosal shear force the silicon nanowire-based devices could withstand before being eliminated, and demonstrated it to be at least 100-fold better than a non-silicon nanowire device.

“In the near term, there are a lot of chronic conditions of the nose, sinuses and other tissues that could immediately benefit from more efficient delivery of currently available drugs using our silicon nanowire drug delivery technology. We are also excited about the longer term potential of delivery of systemic drugs such as insulin via the mucous membrane route,” said Dr. Daniels. In addition, silicon nanowires are inexpensive to make and are biocompatible. Nanosys expects to develop the technology further in partnership with drug manufacturers whose drugs could be made more effective through this delivery approach.

About Nanosys, Inc.

Nanosys, Inc. is a leader in the development of nanotechnology-enabled products utilizing high performance inorganic nanostructures. Nanosys has built one of the broadest technology platforms in the industry with over 650 patents and patent applications covering fundamental areas of nanotechnology. Based in Palo Alto, California and privately held, Nanosys collaborates with industry leaders to develop revolutionary high-value, high-performance products for life sciences, computing, optoelectronics, renewable energy, and defense. Additional information on Nanosys can be found on its website at www.nanosysinc.com.

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