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January 15, 2010 –  Researchers at Northeastern U.’s Electronic Materials Research Institute have created a 3D nanolens from metamaterials to provide more accurate and detailed imaging of nanoscale objects.

Conventional lenses construct an image of an object using ordinary waves, but not the tiny subwavelength details of nano-sized objects that are carried by "evanescent" waves. Previous uses utilized amplified evanescent waves in thin metallic films or metal-dielectric layers, but were restricted to very small thicknesses (<< λ, wavelength) and thus short distances due to losses in the material.

In their new work, reported in the Jan. 11 issue of Applied Physics Letters, the Northeastern researchers arranged and packaged millions of nanowires (20nm dia.) in a way to control how light passes through the lens; by using both ordinary and evanescent waves to construct an image, the lens can depict a clear, high-resolution image of nanosized objects.


Super-resolution imaging with subwavelength resolution by the metamaterial nanolens at 1550nm. The nanolens consists of high aspect ratio metallic nanowires which are embedded in a host dielectric medium. The resolution of the lens is more than 2x better than the diffraction limit. (Image courtesy of Northeastern U.)

From the abstract:

Here, we present an experimental demonstration of super-resolution imaging by a low-loss three-dimensional metamaterial nanolens consisting of aligned gold nanowires embedded in a porous alumina matrix. This composite medium possesses strongly anisotropic optical properties with negative permittivity in the nanowire axis direction, which enables the transport of both far-field and near-field components with low-loss over significant distances (>6λ), and over a broad spectral range. We demonstrate the imaging of large objects, having subwavelength features, with a resolution of at least λ/4 at near-infrared wavelengths.

"This is the best superlens realized so far, and is a significant development in the field of high-resolution optical imaging," said Srinivas Sridhar, prof. and chair of physics at Northeastern, in a statement.

Sridhar claims the group already has capabilities for large-scale production of the nanolenses, and wants to begin manufacturing "in the near future," he added. End applications include biomedical imaging and lithography techniques. The work is funded by the National Science Foundation and the US Air Force.

January 11, 2010 – Researchers at McMaster University in Canada have developed a way to direct microscopic-sized worms along a microchannel device using an electric field, seen as a step toward high-throughput microscreening devices for drug discovery.

The research, described in the Jan. 21 issue of Lab on A Chip, involves the nematode C. elegans, widely used in biomed research because of its similar proteins and molecules to those in humans. Typically the critters are manipulated in mediums of petri dishes, 96-well plates, or pneumatically controlled microfluidic devices. In the new work, the researchers guided the worms forward and in reverse inside a microchannel with an electric field ("electrotaxis"). Current practices observe worms under a microscope as they move randomly or in a direction forced by pressure; the new method lets the worms move in a more "natural" motion. Also among the findings was an observation that the worms’ response to electrotaxis was dependent on age and neuronal development — this, they say, allows for large numbers of worms to be sorted and handled in an automated manner.

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The movement of worms in an electric field. (a) The application of +8 Vcm-1 electric field (E) caused an animal (724μm long) to move with the speed of 308μm s-1 to the right towards the cathode. (b) At a lower field strength in a reverse direction (-3 Vcm-1) the animal (847.5μm long) moved with a speed of 342μm s-1 to the left towards the cathode. Dark thick arrows illustrate the worm’s position. Scale bars are 1mm. (Source: McMaster University)

Implications for the work include more cost-effective ways of conduct rapid screening of tens of thousands of chemicals for drug candidate identification. Also, researchers can further study how neurons respond to electricity, and learn to fabricate new devices to handle and manipulate large numbers of worms.

"This is the first time that worms have been stimulated to move in a micro-channel device in a very precise and directed way," said Bhagwati Gupta, assistant professor of biology, in a statement. "It will allow researchers to study in real time how a proposed drug affects neurons and muscles that control motion of a live specimen."

From the abstract:

In this work, we demonstrate that the electric field can be used as a powerful stimulus to control movement of worms in a microfluidic environment. We found that this response (termed electrotaxis) is directional, fully penetrant and highly sensitive. The characterization of electrotaxis revealed that it is mediated by neuronal activity that varies with the age and size of animals. Although the speed of swimming is unaffected by changes in the electric field strength and direction, our results show that each developmental stage responds to a specific range of electric field with a specific speed. Finally, we provide evidence that the exposure to the electric field has no discernible effect on the ability of animals to survive and reproduce.

January 8, 2010 – The food industry must do a better job of letting everyone know about its research into uses of nanotechnology and nanomaterials, including investigations of potential health and safety risks, according to a report by the House of Lords Science and Technology Committee.

The full report of findings and recommendations claims the food industry’s failure to have transparency and honesty is "unhelpful" to ensure public trust in food safety and scientific development. "Appearing to be secretive about its research is exactly the type of behavior which may bring about the public reaction it is trying to avert," they note in a statement.

Also called for in the report:

– More proactive funding to encourage research into risk assessment of nanomaterials in food. There is only one research team in the UK examining nanomaterials’ toxicological impact "on the gut," for example.

– A publicly available register of food and food packaging materials, possibly posted online, and maintained by the Food Standards Agency. This would offer more accurate and up-to-date information than "a blanket labeling" on products listing any nanomaterials they contain, and would further help contribute to consumer confidence.

– Legislation to ensure all uses of nanomaterials in food are subject to risk assessment procedures. Regulatory definitions of a "nanomaterial" should be based on changes in functionality — e.g., how a substance interacts with the body — to make sure to include nano-sized materials with novel properties vs. their larger forms.

– Collaboration between the UK government and other European Union nations to more precisely define properties characteristic to the nanoscale, phrasing contained in a draft proposal by the Novel Foods Regulation — but which the House of Lords committee claims insufficiently details what such properties comprise.

– Government assurance that practical tests are developed to enforce use on imported food products, addressing the concern of imported foods containing nanomaterials that have not been approved as safe by the EU.

"The use of nanotechnologies in food and food packaging is likely to grow significantly over the next decade. The technologies have the potential to deliver some significant benefits to consumers, but it is important that detailed and thorough research into potential health and safety implications in this area is undertaken now to ensure that any possible risks are identified," stated Lord Krebs, chair of the Science and Technology Committee’s inquiry into Nanotechnologies and Food. "The Government and Research Councils have a responsibility to ensure that this research takes place and must now take a proactive approach to identifying and funding appropriate research."

January 4, 2010 –  Silicon magnetic sensors, among the most ubiquitous types of sensors sold, will continue to see strong growth in 2010 thanks to demand from a trio of key markets, according to a report from iSuppli.

Sales of these sensors, used in everything from industrial motors (rotator positioning and control loads) to automotive (rotation speed angle and position) and low-cost consumer products, will surge from $821M in 2009 to $1.4B in 2013; that translates to about 2.8B magnetic sensor ICs and switches to 5B units. Their varying use also translates into varied costs, from 10¢ to several dollars each, notes Richard Dixon, senior analyst for MEMS and and sensors at iSuppli, in a statement.

Generally speaking, silicon-based magnetic sensors (Hall effect and magnetoresistive) are taking over for legacy technologies that can’t keep up with performance and formfactor demands, Dixon explains. "Silicon sensors are outgunning competition from potentiometers, Reed switches, and microswitches by eliminating issues with wear, by incorporating electronics on-chip for more intelligence per area, on robustness, and on cost and size," he writes. "Hall effect sensors ICs and switches largely dominate the silicon magnetic sensor IC market, but increasingly, AMR and also giant magnetoresistance (GMR) sensors are used for high-performance applications."

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Global magnetic silicon sensor forecast (US $M). (Source: iSuppli)

In autos, body and powertrain systems are areas of biggest growth potential; in the body segment alone, an average of 9.4 sensors/switches will be used by 2013, up from 6.7 in 2009. Five or more different magnetic technologies could be used, for example, in precise measurement of steering wheel angle and safety systems. In electronics, switches are used for noting when appliance doors or computing/camera cases are opened and shut. In other consumer products, linear sensors and switches monitor fluid levels in drug delivery systems and even automatic coffee dispensers.

One key emerging application is electronic compass functionality in GPS-equipped mobile phones, which relies on 3-axis silicon magnetometers. Look for these types of devices to account for a third of all magnetic sensors by 2013, vs. just 10% in 2008.

Currently, top vendors for magnetic sensors are Asahi Kasei Microsystems and Allegro, who dominate the market for magnetic sensors used in low-cost switches for consumer applications, PCs and notebooks, Dixon notes (AKM snatched the top spot thanks to its exposure to those electronic compasses). Other players including Micronas, Infineon, and NXP, eyeing emerging markets in those compasses as well as rotation sensors in car engines. Newer entrants include Sensitec — which is levering older asymmetric magnetoresistance (AMR) technology from an IBM plant — and austriamicrosystems.

December 23, 2009 – A new $6.5M award from the National Institute of Standards and Technology (NIST) will support efforts from Brewer Science and Southwest Nanotechnologies (SWeNT) to improve production of high-purity, high-quality metallic and semiconducting carbon nanotube (CNT) inks.

Under the funding, part of NIST’s Technology Innovation Program aimed to support "high-risk, high-reward research in areas of critical need," the two firms will research and develop cost-effective commercial-scale production of the CNTs and inks for a variety of potential uses in various electronics applications: optical devices, photovoltaic cells, batteries, supercapacitors, lighting, flexible electronic devices, and sensors. The work will combine SWeNT’s single-wall carbon nanotube technology and production capabilities with Brewer Science’s background in CNTs purification, separation, and dispersion.

"CNT inks and films are poised to enable several important new technologies that address national needs, and we are very pleased to have our development efforts supported and recognized," stated Terry Brewer, president/CEO of Brewer Science.

December 22, 2009 – Researchers at Rice university and Baylor College of Medicine have created a nanoparticle trackable with MRIs that locates cancer cells, tags them with a fluorescent dye, and kills them with heat — a first example of "thernostic," or essentially patient-customized, medical treatment.

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Breast cancer cells after treatment with light-activated, antibody-containing nanocomplexes, which specifically target the cells; upon laser activation they convert light to heat and kill the cancer cells. Dead cells are shown in red within the area where laser was applied (white circle), and live cells are shown in green. (Source: Rice U.)

Their work, published in the Nov. 17 issue of Advanced Functional Materials, centers on the idea of noninvasive "biodistribution," i.e., how and where tiny particles go inside the body. The particles involved are based on "nanoshells," structures invented in the 1990s and currently being used in human clinical trials for cancer treatment; these structures harvest light that would otherwise pass harmlessly through the body, and convert it into heat to attack and kill tumors. The teams from Rice and Baylor added a fluorescent dye to these nanoshells to make them glow when struck by near-infrared light. Leaving a few-nanometer-wide gap between the dye molecules and nanoshell surface increased light emission by 40×50× they note; in this gap they inserted an iron oxide, detectable with MRI; they also attached an antibody to help the particles bind to breast and ovarian cancer cells. The team tracked the nanoparticles, confirming that they target cancer cells and then destroy them with heat.

"What’s nice is that every single component of this has been approved or is on a path toward FDA approval," stated study co-author Naomi Halas, Rice prof. in electrical and computer engineering and prof. of chemistry and biomedical engineering. "We’re putting together components that all have good, proven track records." And with four options (two for imaging, two for therapy), "we envision this as a platform technology that will present practitioners with a choice of options for directed treatment," added Amit Joshi, assistant professor in the Baylor College of Medicine’s division of molecular imaging.

From the paper abstract:

Integrating multiple functionalities into individual nanoscale complexes is of tremendous importance in biomedicine, expanding the capabilities of nanoscale structures to perform multiple parallel tasks. Here, the ability to enhance two different imaging technologies simultaneously – fluorescence optical imaging and magnetic resonance imaging – with antibody targeting and photothermal therapeutic actuation is combined all within the same nanoshell-based complex. The nanocomplexes are constructed by coating a gold nanoshell with a silica epilayer doped with Fe3O4 and the fluorophore ICG, which results in a high T2 relaxivity (390 mM-1 s-1) and 45× fluorescence enhancement of ICG. Bioconjugate nanocomplexes target HER2+ cells and induce photothermal cell death upon near-IR illumination.

Tests so far involve lab cell cultures, but the researchers are optimistic that MRI tracking will help them move the work ahead to testing on whole tumors in animals. Testing on humans is said to be at least two years away, though the researchers already envision how it would work: a patient gets a shot containing nanoparticles with antibodies tailored for that patient’s specific cancer; using near-infrared light or MRI, doctors track the particles until they hit the tumors and then destroy them with heat. Ultimately, specific versions of the nanoparticles could target tumors with different stages (e.g. early-stage which is difficult to diagnose and treat), and use different antibody labels to treat different forms of the disease.

December 18, 2009 – HP expects its latest inertial MEMS sensing technology to enable new classes of applications. One that has attracted attention is bridge monitoring.

Environmental and engineering consulting services company CH2M Hill has had a more than 20-year relationship with HP Labs (Palo Alto, CA) and HP Technology Development (Corvallis, OR), and is working with HP to develop at least one or two "champion" applications for HP’s technology, according to Michael O’Halloran, director of technology I&AT. "The ability to measure minute amounts of movement and doing so independently — i.e., being able to track location independent of satellites and other means of transmission — is especially attractive to the kinds of projects in which CH2M Hill is involved," he told Small Times.

Conventional bridge monitoring is time-consuming, labor intensive, and not particularly revealing, so a device that could precisely monitor the structure could be quite revealing, noted O’Halloran. Depending on the bridge, visual inspection is done every one or two years; every four or five years, a very detailed visual inspection is done with someone crawling all over the bridge looking for signs of failure, he explained. "Some states are beginning to use analytical instrumentation in addition to visual inspection, but visual inspection is still the traditional method used," he said.

CH2M Hill is actively seeking partnerships with states to develop monitoring algorithms and obtain data that hopefully will indicate monitors that can yield data at least comparable to current methods. Conventional sensing systems use costly instruments that are also costly to install, have to be hardwired, and do not have a very wide range, O’Halloran added. "We’re hoping the HP technology will expand the range at which the instrument looks and lower the cost of installation," he said. "If we can’t get the cost down, then it can’t be effectively deployed in a large application." CH2M Hill believes there is already some evidence to suggest that HP’s new technology will work.

With much of the infrastructure in the US built during the Eisenhower administration, it is critical to develop a logical way to prioritize allocation of repair and replacement funds. If HP’s sensing technology could be developed for monitoring such structures, it would be a way to address the prioritization challenge, according to O’Halloran.

SWeNT gets grants for new CNTs


December 18, 2009

December 18, 2009 – Southwest Nanotechnologies Inc. (SWeNT) has received two grants from the Oklahoma Center for the Advancement of Science and Technology, to help develop new single-walled carbon nanotubes (CNT) with improved electrical conductivity and transparency.

Under one of the grants, coming through the Oklahoma Applied Research Support (OARS) program, SWeNT will develop materials targeted for use in CNT-printed electrodes for next-generation LED lighting applications that consume up to a third less power; other applications beyond LED lighting could include photovoltaics, supercapacitors, batteries, and displays, according to SWeNT CEO David Arthur. The grant amount was not disclosed, though OARS describes its program’s funding levels in two types: $10K-$45K (1-2 years) or $300K (1-3 years), 1:1 matched.

The other grant, pegged at about $60K, will bring in three undergraduate interns to help work on current projects at SWeNT.

"OCAST’s support for our employment of interns to assist us in new technology development will help us on the OARS activity as well as other research activities we have planned," Arthur said in a statement, adding that "SWeNT would not be a leading carbon nanotubes producer today without OCAST support."

December 18, 2009–Diagnostic Nano Technology Corporation (DNA), a subsidiary of Avisio, Inc., says that with the early laboratory success of its Instant Detect Technology in the detection of certain viruses that cause Dengue Fever, it plans to begin testing the nanotechnology on the detection of the H1N1 virus.

Instant Detect is a portable nano-based technology that operates in the field and provides immediately-available results that do not require the expertise of a specialized lab technician to read. The technology is expected to be used by individuals in the health care and agricultural industries to detect disease-causing pathogens that can impact global food supplies and human health.

"Ongoing testing of this type is a necessary component in the process of selecting DNA’s initial human application development projects," says Amro Albanna, CEO of DNA and Avisio, Inc. "We are cautiously optimistic about the market opportunity that exists for DNA’s Instant Detect product, especially with regard to potential human applications. We realize that we are early in the process and still have a number of milestones to reach, including but not limited to further proof of concept, the ability to produce product at scale, third-party validation and regulatory approvals, before we can begin to market a product."

December 14, 2009 –  Researchers at Stanford disclosed their latest work at this year’s International Electron Devices Meeting (IEDM) on combining carbon nanotubes (CNT) and logic circuits to devise new techniques for preventing flaws and building multilayer chip prototypes. The transistors are said to be grouped in the same "cascading" sequences as for computational logic and memory, with processes compatible with standard industrial-scale VLSI (very large scale integration) manufacturing.

"Carbon nanotube transistor technology has moved beyond the realm of scientific discovery and into engineering research," stated H.-S. Philip Wong, professor of electrical engineering at Stanford and a co-author of the paper. "We are now able to construct devices and build circuits on a wafer scale as opposed to previous ‘one-of-a-kind’ type demonstrations."

The chips employ two techniques already developed at Stanford: one (invented in 2007) to enable working transistors regardless of whether the CNTs are straight, and another (invented in 2008) to enable VLSI-scale fabrication of nanotube transistors on a chip. A third, newly developed technique announced at this year’s IEDM is a process for reliable removal of "metallic" CNTs that can conduct electrical current and short-circuit transistors. This technique, dubbed "VLSI-compatible metallic nanotube removal" (VMR), makes practical a previous idea (from Paul Collins and IBM colleagues, circa 2001) to break up the CNTs by exposing them to light, by creating a grid of electrodes to "zap" them away; this same grid can then be etched to produce any circuit design.


An electron microscope image showing carbon nanotube transistors (CNTs) arranged in an integrated logic circuit. (Source: Stanford)

Another IEDM disclosure from Stanford follows up on the VMR work by creating the first multilayer CNT 3D integrated circuit. 3D circuits are already being stacked and connected with conventional chipmaking materials, but the new research shows it can be done with CNTs integrated from the start as a 3D design that yields a higher density of connections among the layers. A prototype three-layer chip with dozens of CNT transistors were connected in functioning gates by nanotube and metal wiring — key to the achievement was a "relatively low-temperature process" that transfers CNTs from a quartz wafer onto a silicon chip.

Still a challenge is to increase the number of CNTs that can be patterned onto a given area on the chip, to thus scale up to modern chip design complexity of millions of transistors. The Semiconductor Research Corporation’s Focus Center Research Program and the National Science Foundation helped fund the research.