David Kirkpatrick

May 12, 2010

DNA-based logic chips

Very cool and very fascinating in terms of extreme mass production.

The release:

DNA could be backbone of next generation logic chips

IMAGE: This is Duke University’s Chris Dwyer.

Click here for more information.

DURHAM, N.C. – In a single day, a solitary grad student at a lab bench can produce more simple logic circuits than the world’s entire output of silicon chips in a month.

So says a Duke University engineer, who believes that the next generation of these logic circuits at the heart of computers will be produced inexpensively in almost limitless quantities. The secret is that instead of silicon chips serving as the platform for electric circuits, computer engineers will take advantage of the unique properties of DNA, that double-helix carrier of all life’s information.

In his latest set of experiments, Chris Dwyer, assistant professor of electrical and computer engineering at Duke’s Pratt School of Engineering, demonstrated that by simply mixing customized snippets of DNA and other molecules, he could create literally billions of identical, tiny, waffle-looking structures.

Dwyer has shown that these nanostructures will efficiently self-assemble, and when different light-sensitive molecules are added to the mixture, the waffles exhibit unique and “programmable” properties that can be readily tapped. Using light to excite these molecules, known as chromophores, he can create simple logic gates, or switches.

These nanostructures can then be used as the building blocks for a variety of applications, ranging from the biomedical to the computational.

IMAGE: This is a closeup of a waffle.

Click here for more information.

“When light is shined on the chromophores, they absorb it, exciting the electrons,” Dwyer said. “The energy released passes to a different type of chromophore nearby that absorbs the energy and then emits light of a different wavelength. That difference means this output light can be easily differentiated from the input light, using a detector.”

Instead of conventional circuits using electrical current to rapidly switch between zeros or ones, or to yes and no, light can be used to stimulate similar responses from the DNA-based switches – and much faster.

“This is the first demonstration of such an active and rapid processing and sensing capacity at the molecular level,” Dwyer said. The results of his experiments were published online in the journal Small. “Conventional technology has reached its physical limits. The ability to cheaply produce virtually unlimited supplies of these tiny circuits seems to me to be the next logical step.”

DNA is a well-understood molecule made up of pairs of complimentary nucleotide bases that have an affinity for each other. Customized snippets of DNA can cheaply be synthesized by putting the pairs in any order. In their experiments, the researchers took advantage of DNA’s natural ability to latch onto corresponding and specific areas of other DNA snippets.

Dwyer used a jigsaw puzzle analogy to describe the process of what happens when all the waffle ingredients are mixed together in a container.

“It’s like taking pieces of a puzzle, throwing them in a box and as you shake the box, the pieces gradually find their neighbors to form the puzzle,” he said. “What we did was to take billions of these puzzle pieces, throwing them together, to form billions of copies of the same puzzle.”

IMAGE: These are many waffles.

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In the current experiments, the waffle puzzle had 16 pieces, with the chromophores located atop the waffle’s ridges. More complex circuits can be created by building structures composed of many of these small components, or by building larger waffles. The possibilities are limitless, Dwyer said.

In addition to their use in computing, Dwyer said that since these nanostructures are basically sensors, many biomedical applications are possible. Tiny nanostructures could be built that could respond to different proteins that are markers for disease in a single drop of blood.

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Dwyer’s research is supported by the National Science Foundation, the Air Force Research Laboratory, the Defense Advanced Research Projects Agency and the Army Research Office. Other members of the Duke team were Constantin Pistol, Vincent Mao, Viresh Thusu and Alvin Lebeck

February 12, 2010

Nanogenerators and electric clothes

(Number two of two posts on nanotechnology and electricity. Hit this link for part one)

The idea of smart clothes has been around for ages. Looks like this might just be a breakthrough to electric clothing becoming a reality.

That oughta bring a whole new meaning to “social networking.” Thank you, thank you, I’ll be here all weekend. Be sure and come back tomorrow for the complimentary Saturday buffet and half-price happy hour.

The release:

New fiber nanogenerators could lead to electric clothing

By Sarah Yang, Media Relations | 12 February 2010

BERKELEY — In research that gives literal meaning to the term “power suit,” University of California, Berkeley, engineers have created energy-scavenging nanofibers that could one day be woven into clothing and textiles.

These nano-sized generators have “piezoelectric” properties that allow them to convert into electricity the energy created through mechanical stress, stretches and twists.

“This technology could eventually lead to wearable ‘smart clothes’ that can power hand-held electronics through ordinary body movements,” said Liwei Lin, UC Berkeley professor of mechanical engineering and head of the international research team that developed the fiber nanogenerators.

Because the nanofibers are made from organic polyvinylidene fluoride, or PVDF, they are flexible and relatively easy and cheap to manufacture.

Although they are still working out the exact calculations, the researchers noted that more vigorous movements, such as the kind one would create while dancing the electric boogaloo, should theoretically generate more power. “And because the nanofibers are so small, we could weave them right into clothes with no perceptible change in comfort for the user,” said Lin, who is also co-director of the Berkeley Sensor and Actuator Center at UC Berkeley.

The fiber nanogenerators are described in this month’s issue of Nano Letters, a peer-reviewed journal published by the American Chemical Society.

The goal of harvesting energy from mechanical movements through wearable nanogenerators is not new. Other research teams have previously made nanogenerators out of inorganic semiconducting materials, such as zinc oxide or barium titanate. “Inorganic nanogenerators — in contrast to the organic nanogenerators we created — are more brittle and harder to grow in significant quantities,” Lin said.

The tiny nanogenerators have diameters as small as 500 nanometers, or about 100 times thinner than a human hair and one-tenth the width of common cloth fibers. The researchers repeatedly tugged and tweaked the nanofibers, generating electrical outputs ranging from 5 to 30 millivolts and 0.5 to 3 nanoamps.

Furthermore, the researchers report no noticeable degradation after stretching and releasing the nanofibers for 100 minutes at a frequency of 0.5 hertz (cycles per second).

Lin’s team at UC Berkeley pioneered the near-field electrospinning technique used to create and position the polymeric nanogenerators 50 micrometers apart in a grid pattern. The technology enables greater control of the placement of the nanofibers onto a surface, allowing researchers to properly align the fiber nanogenerators so that positive and negative poles are on opposite ends, similar to the poles on a battery.

Without this control, the researchers explained, the negative and positive poles might cancel each other out and reducing energy efficiency.

The researchers demonstrated energy conversion efficiencies as high as 21.8 percent, with an average of 12.5 percent.

“Surprisingly, the energy efficiency ratings of the nanofibers are much greater than the 0.5 to 4 percent achieved in typical power generators made from experimental piezoelectric PVDF thin films, and the 6.8 percent in nanogenerators made from zinc oxide fine wires,” said the study’s lead author, Chieh Chang, who conducted the experiments while he was a graduate student in mechanical engineering at UC Berkeley.

“We think the efficiency likely could be raised further,” Lin said. “For our preliminary results, we see a trend that the smaller the fiber we have, the better the energy efficiency. We don’t know what the limit is.”

Other co-authors of the study are Yiin-Kuen Fuh, a UC Berkeley graduate student in mechanical engineering; Van H. Tran, a graduate student at the Technische Universität München (Technical University of Munich) in Germany; and Junbo Wang, a researcher at the Institute of Electronics at the Chinese Academy of Sciences in Beijing, China.

The National Science Foundation and the Defense Advanced Research Projects Agency helped support this research.

fiber nanogenerator
Shown is a fiber nanogenerator on a plastic substrate created by UC Berkeley scientists. The nanofibers can convert energy from mechanical stresses and into electricity, and could one day be used to create clothing that can power small electronics. (Chieh Chang, UC Berkeley)

February 2, 2010

Spider man, spider man …

… does whatever a spider can.

I’ll just let the release from yesterday finish this thought process for me:

New adhesive device could let humans walk on walls

Could humans one day walk on walls, like Spider-Man? A palm-sized device invented at Cornell that uses water surface tension as an adhesive bond just might make it possible.

The rapid adhesion mechanism could lead to such applications as shoes or gloves that stick and unstick to walls, or Post-it-like notes that can bear loads, according to Paul Steen, professor of chemical and biomolecular engineering, who invented the device with Michael Vogel, a former postdoctoral associate.

The device is the result of inspiration drawn from a beetle native to Florida, which can adhere to a leaf with a force 100 times its own weight, yet also instantly unstick itself. Research behind the device is published online Feb. 1 in Proceedings of the National Academy of Sciences.

The device consists of a flat plate patterned with holes, each on the order of microns (one-millionth of a meter). A bottom plate holds a liquid reservoir, and in the middle is another porous layer. An electric field applied by a common 9-volt battery pumps water through the device and causes droplets to squeeze through the top layer. The surface tension of the exposed droplets makes the device grip another surface – much the way two wet glass slides stick together.

“In our everyday experience, these forces are relatively weak,” Steen said. “But if you make a lot of them and can control them, like the beetle does, you can get strong adhesion forces.”

For example, one of the researchers’ prototypes was made with about 1,000 300-micron-sized holes, and it can hold about 30 grams – more than 70 paper clips. They found that as they scaled down the holes and packed more of them onto the device, the adhesion got stronger. They estimate, then, that a one-square-inch device with millions of 1-micron-sized holes could hold more than 15 pounds.

To turn the adhesion off, the electric field is simply reversed, and the water is pulled back through the pores, breaking the tiny “bridges” created between the device and the other surface by the individual droplets.

The research builds on previously published work that demonstrated the efficacy of what’s called electro-osmotic pumping between surface tension-held interfaces, first by using just two larger water droplets.

One of the biggest challenges in making these devices work, Steen said, was keeping the droplets from coalescing, as water droplets tend to do when they get close together. To solve this, they designed their pump to resist water flow while it’s turned off.

Steen envisions future prototypes on a grander scale, once the pump mechanism is perfected, and the adhesive bond can be made even stronger. He also imagines covering the droplets with thin membranes – thin enough to be controlled by the pump but thick enough to eliminate wetting. The encapsulated liquid could exert simultaneous forces, like tiny punches.

“You can think about making a credit card-sized device that you can put in a rock fissure or a door, and break it open with very little voltage,” Steen said. “It’s a fun thing to think about.”

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The research was funded primarily by the Defense Advanced Research Projects Agency and also by the National Science Foundation.

June 4, 2009

Nanoscale zipper cavities

More nanotech news.

The release:

Caltech scientists create nanoscale zipper cavity that responds to single photons of light

Device could be used for highly sensitive force detection, optical communications and more

IMAGE: Scanning electron microscope image of an array of “zipper ” optomechanical cavities. The scale and sensitivity of the device is set by its physical mass (40 picograms/40 trillionths of a gram)…

Click here for more information. 

PASADENA, Calif.—Physicists at the California Institute of Technology (Caltech) have developed a nanoscale device that can be used for force detection, optical communication, and more. The device exploits the mechanical properties of light to create an optomechanical cavity in which interactions between light and motion are greatly strengthened and enhanced. These interactions, notes Oskar Painter, associate professor of applied physics at Caltech, and the principal investigator on the research, are the largest demonstrated to date.

The device and the work that led to it are described in a recent issue of the journal Nature.

The fact that photons of light, despite having no mass, nonetheless carry momentum and can interact with mechanical objects is an idea that dates back to Kepler and Newton. The mechanical properties of light are also known to limit the precision with which one can measure an object’s position, since simply by using light to do the measurement, you apply a force and disturb the object.

It was important to consider these so-called back-action effects in the design of devices to measure weak, classical forces. Such considerations were part of the development of gravity-wave detectors like the Laser Interferometer Gravitational-Wave Observatory (LIGO). These sorts of interferometer-based detectors have also been used at much smaller scales, in scanning probe instruments used to detect or image atomic surfaces or even single electron spins.

To get an idea of how these systems work, consider a mirror attached to a floppy cantilever, or spring. The cantilever is designed to respond to a particular force—say, a magnetic field. Light shining down on the mirror will be deflected when the force is detected—i.e., when the cantilever moves—resulting in a variation in the light beam’s intensity that can then be detected and recorded.

“LIGO is a huge multikilometer-scale interferometer,” notes Painter. “What we did was to take that and scale it all the way down to the size of the wavelength of light itself, creating a nanoscale device.”

They did this, he explains, because as these interferometer-based detectors are scaled down, the mechanical properties of light become more pronounced, and interesting interactions between light and mechanics can be explored.

“To this end, we made our cantilevers many, many times smaller, and made the optical interaction many, many times larger,” explains Painter.

They call this nanoscale device a zipper cavity because of the way its dual cantilevers—or nanobeams, as Painter calls them—move together and apart when the device is in use. “If you look at it, it actually looks like a zipper,” Painter notes.

“Zipper structures break new ground on coupling photonics with micromechanics, and can impact the way we measure motion, even into the quantum realm,” adds Kerry Vahala, Caltech’s Ted and Ginger Jenkins Professor of Information Science and Technology and professor of applied physics, and one of the paper’s authors. “The method embodied in the zipper design also suggests new microfabrication design pathways that can speed advances in the subject of cavity optomechanics as a whole.”

To create their zipper cavity device, the researchers made two nanobeams from a silicon chip, poking holes through the beams to form an effective optical mirror. Instead of training a light down onto the nanobeams, the researchers used optical fibers to send the light “in plane down the length of the beams,” says Painter. The holes in the nanobeams intercept some of the photons, circulating them through the cavity between the beams rather than allowing them to travel straight through the device.

Or, to be more precise, the circulating photons actually create the cavity between the beams. As Painter puts it: “The mechanical rigidity of the structure and the changes in its optical response are predominantly governed by the internal light field itself.”

Such an interaction is possible, he adds, because the structure is precisely designed to maximize the transfer of momentum from the input laser’s photons to the mechanical nanobeams. Indeed, a single photon of laser light zipping through this structure produces a force equivalent to 10 times that of Earth’s gravity. With the addition of several thousand photons to the cavity, the nanobeams are effectively suspended by the laser light.

Changes in the intensity and other properties of the light as it moves along the beams to the far end of the chip can be detected and recorded, just as with any large-scale interferometer.

The potential uses for this sort of optomechanical zipper cavity are myriad. It could be used as a sensor in biology by coating it with a solution that would bind to, say, a specific protein molecule that might be found in a sample. The binding of the protein molecule to the device would add mass to the nanobeams, and thus change the properties of the light traveling through them, signaling that such a molecule had been detected. Similarly, it could be used to detect other ultrasmall physical forces, Painter adds.

Zipper cavities could also be used in optical communications, where circuits route information via optical beams of different colors, i.e., wavelengths. “You could control and manipulate what the optical beams of light are doing,” notes Painter. “As the optical signals moved around in a circuit, their direction or color could be manipulated via other control light fields.” This would create tunable photonics, “optical circuits that can be tuned with light.”

Additionally, the zipper cavity could lead to applications in RF-over-optical communications and microwave photonics as well, where a laser source is modulated at microwave frequencies, allowing the signals to travel for kilometers along optical fibers. In such systems, the high-frequency mechanical vibrations of the zipper cavity could be used to filter and recover the RF or microwave signal riding on the optical wave.

 

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Other authors on the Nature paper, “A picogram- and nanometre-scale photonic-crystal optomechanical cavity,” include graduate students Matt Eichenfield (the paper’s first author) and Jasper Chan, and postdoctoral scholar Ryan Camacho.

Their research was supported by a Defense Advanced Research Projects Agency seeding effort, and an Emerging Models and Technologies grant from the National Science Foundation.

March 27, 2009

Nanogenerators

Very cool nanotech. Not sure how close this is to market, but man it’s very cool.

The release:

New nanogenerator may charge iPods and cell phones with a wave of the hand

IMAGE: Pictured is a schematic illustration shows the microfiber-nanowire hybrid nanogenerator, which is the basis of using fabrics for generating electricity.

Click here for more information. 

SALT LAKE CITY, March 26, 2009 — Imagine if all you had to do to charge your iPod or your BlackBerry was to wave your hand, or stretch your arm, or take a walk? You could say goodbye to batteries and never have to plug those devices into a power source again.

In research presented here today at the American Chemical Society’s 237th National Meeting, scientists from Georgia describe technology that converts mechanical energy from body movements or even the flow of blood in the body into electric energy that can be used to power a broad range of electronic devices without using batteries.

“This research will have a major impact on defense technology, environmental monitoring, biomedical sciences and even personal electronics,” says lead researcher Zhong Lin Wang, Regents’ Professor, School of Material Science and Engineering at the Georgia Institute of Technology. The new “nanogenerator” could have countless applications, among them a way to run electronic devices used by the military when troops are far in the field.

The researchers describe harvesting energy from the environment by converting low-frequency vibrations, like simple body movements, the beating of the heart or movement of the wind, into electricity, using zinc oxide (ZnO) nanowires that conduct the electricity. The ZnO nanowires are piezoelectric — they generate an electric current when subjected to mechanical stress. The diameter and length of the wire are 1/5,000th and 1/25th the diameter of a human hair.

In generating energy from movement, Wang says his team concluded that it was most effective to develop a method that worked at low frequencies and was based on flexible materials. The ZnO nanowires met these requirements. At the same time, he says a real advantage of this technology is that the nanowires can be grown easily on a wide variety of surfaces, and the nanogenerators will operate in the air or in liquids once properly packaged. Among the surfaces on which the nanowires can be grown are metals, ceramics, polymers, clothing and even tents.

“Quite simply, this technology can be used to generate energy under any circumstances as long as there is movement,” according to Wang.

To date, he says that there have been limited methods created to produce nanopower despite the growing need by the military and defense agencies for nanoscale sensing devices used to detect bioterror agents. The nanogenerator would be particularly critical to troops in the field, where they are far from energy sources and need to use sensors or communication devices. In addition, having a sensor which doesn’t need batteries could be extremely useful to the military and police sampling air for potential bioterrorism attacks in the United States, Wang says.

While biosensors have been miniaturized and can be implanted under the skin, he points out that these devices still require batteries, and the new nanogenerator would offer much more flexibility.

A major advantage of this new technology is that many nanogenerators can produce electricity continuously and simultaneously. On the other hand, the greatest challenge in developing these nanogenerators is to improve the output voltage and power, he says.

Last year Wang’s group presented a study on nanogenerators driven by ultrasound. Today’s research represents a much broader application of nanogenerators as driven by low-frequency body movement.

 

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The study was funded by the Defense Advanced Research Projects Agency, the Department of Energy, the National Institutes of Health and the National Science Foundation.

The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 154,000 members, ACS is the world’s largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.

 

October 2, 2008

Zyvex Labs wins almost $10M DARPA award

The press release from Zyvex Labs:

Zyvex-led Atomically Precise Manufacturing Consortium Receives Award From DARPA and the State of Texas Emerging Technology Fund

Combined Award totals $9.7M

RICHARDSON, Texas, Oct. 2 /PRNewswire/ — Zyvex Labs today announced the award of a $9.7M program funded by DARPA (Defense Advanced Research Projects Agency) and Texas’ ETF (Emerging Technology Fund). The goal of this effort is to develop a new manufacturing technique that enables “Tip-Based Nanofabrication” to accelerate the transition of nanotechnology from the laboratory to commercial products. Starting with the construction of ‘one-at-a-time’ atomically precise silicon structures, the Consortium initially plans to develop atomically precise, ‘quantum dot’ nanotech-based products in volume at practical production rates and costs. Harnessing this capability will position the United States and Texas with the fundamental technology to develop next-generation quantum dot applications for military and commercial applications such as advanced communications, metrology, and quantum computers. The spin-off nanomanufacturing capabilities from that early application will result in revolutionary nanotech products in follow-on development.

The charter industry APMC members are Zyvex Labs, General Dynamics, Integrated Circuit Scanning Probe Instruments, and Vought Aircraft; while Texas Higher Education members include the University of Texas at Dallas, the University of Texas at Austin and the University of North Texas. Other Higher Education members are the University of Central Florida and the University of Illinois at Urbana-Champaign. Government and non-profit consortium members are the US National Institute of Standards and Technology (NIST) and the North Texas Regional Center for Innovation & Commercialization (NTXRCIC).  Other consortium members of all three types are expected to be added as the program progresses into later stages.

“We are extremely proud to receive this award,” said John Randall, Ph.D., Vice President of Zyvex Labs and Principal Investigator for the APMC research program. “The technologies developed by this program will be the first to allow robust three-dimensional solid structures to be created with atomic precision under computer control.  While, historically, this falls in line with ongoing efforts throughout human history to improve manufacturing precision, it is revolutionary because it will achieve unprecedented precision by taking advantage of the quantized nature of matter.”

“DARPA is investing in breakthrough approaches to nanomanufacturing.  Our goal is to develop the capability to fabricate nanostructures in such a way that we can control position, size, shape and orientation at the nanometer scale, which is not possible today,” said Tom Kenny, DARPA Program Manager. “If we can demonstrate this, we will be able to truly unlock the potential capabilities of nanotechnology.”

To almost double the resources supporting the APMC, the $5M in DARPA research funding is ‘matched’ by the Texas ETF of $4.7M to achieve a total program size of $9.7M. The North Texas Regional Center for NTXRCIC will serve as the ‘fiscal agent’ to administer the APMC funding from the ETF; and will also sponsor the “APMC Advisory Board” of senior industry and scientific experts that will direct the overall strategy and early commercialization activities of the APMC.

“As the regional representative for the ETF, we are excited about our role in the APMC consortium,” said R. Mike Lockerd, Executive Director of the NTXRCIC.  “Under the leadership of Zyvex Labs, APMC combines business, scientific and academic excellence; and we are confident that this consortium will develop ground-breaking technologies which may redefine how we create, manufacture and commercialize future products in Texas.”

“This is a most exciting program and is very well aligned with my group’s goals,” said Richard M. Silver, a Program Manager in the Nanomanufacturing Program at the National Institute for Standards and Technology (NIST). “It is one of those unique programs where the basic work in advanced scientific institutions is aligned with industry toward a revolutionary and technologically important goal.”

“We are both thrilled and proud to be an integral part of the innovative APMC consortium project,” said Robert M. Wallace, PhD, the principal investigator and Professor of Materials Science and Engineering, Electrical Engineering and Physics at the University of Texas at Dallas. “The program taps our extensive expertise and capability to manipulate silicon surfaces at the atomic scale and provides a conduit for our research to be translated into a viable nanotechnology product.  This industry-university-government partnership supporting the consortium presents us with a unique opportunity to impact Texas and the world of nanotechnology.”

About DARPA

The Defense Advanced Research Projects Agency (DARPA) is the central research and development organization for the Department of Defense (DoD). It manages and directs selected basic and applied research and development projects for DoD, and pursues research and technology where risk and payoff are both very high and where success may provide dramatic advances for traditional military roles and missions.

About the Texas ETF

The $200M ETF was initially enacted by the Texas Legislature in June 2005 to expedite the commercialization of technologies and creation of high-tech jobs in Texas; and one component of the fund is used to match federal research funds.

About the North Texas RCIC

The NTXRCIC serves the North Texas Region to identify, evaluate and provide matching funding for new technology projects with the aim of increasing cooperation between industrial, financial, and academic entities, and of creating new commercial entities based on those technologies to establish new technical industry sectors in the region.

About the APMC

Zyvex Labs leads the APMC consortium, which is comprised of government, university, and industry partners. The consortium was formed to maximize the commercialization opportunities for the technology developed in this program. Consortium members include: General Dynamics, ICSPI, NIST, Vought Aircraft, Zyvex Labs, the University of Central Florida, the University of Illinois, the University of North Texas, the University of Texas at Austin, and the University of Texas at Dallas, and the North Texas RCIC.

Source: Zyvex
   
Web site:  http://www.zyvex.com/