Tag Archives: Small Times Magazine

November 30, 2009 – Researchers at Argonne National Laboratory and the University of Chicago have created a new way to target cancer cells with nanotechnology: tiny magnetic discs that deliver a 90% cell destruction rate.

Their work, published online in Nature Materials, involves fabricating 60nm-thick nickel-iron discs with a spin-vortex ground state. Applying an alternating magnetic field shifts the vortices, creating an oscillation that basically rips up the cancer cell membranes, causing them to die.

Details of the microdisc fabrication process, described as "low-cost" and resulting in "uniformly sized microdiscs":

– Optical lithography: Photoresist (N-1410 negative-tone) spin-coated onto a 2-in. silicon wafer, a mask placed in contact with the prebaked photoresist and illuminated with UV light, and unexposed resist removed via organic solvent;
– Deposition of a 5nm underlayer gold via magnetron sputtering, followed by 60nm of permalloy and another 5nm of gold layer;
– Lift-off process in acetone.

Fabrication of MDs by optical lithography and magnetron sputtering. (Source: Nature Materials)

From the journal paper abstract:

Because reduced sensitivity of cancer cells toward apoptosis leads to inappropriate cell survival and malignant progression, selective induction of apoptosis is of great importance for the anticancer therapeutic strategies. We show that the spin-vortex-mediated stimulus creates two dramatic effects: compromised integrity of the cellular membrane, and initiation of programmed cell death.

A low-frequency field of a few 10s of hertz applied for only 10min was enough to destroy ~90% of cancer-cells in vitro, they claim. And the system also works with much less heat/energy than other cancer cell-busting methods, they note.

November 18, 2009 – Scientists from IBM Research in Zurich, Switzerland, have created a diagnostic test using a silicon chip to more quickly diagnose diseases.

Their collaborative work with the U. Hospital of Base, published in the December issue of Lab on a Chip, uses capillary forces — the process whereby liquid rises in narrow tubes, or drawn into tiny openings — to analyze tiny samples of serum or blood to find disease markers, typically proteins detectable in human blood.

How it works: 1μl sample is pipetted onto a silicon-compound chip (1cm×5cm), and pushed by a 180μm capillary pump through a set of "micrometer-wide channels" onto a series of mesh structures, which prevent clogging and formation of air bubbles. It then passes through a region containing tiny amounts of a detection antibody (70 picoliters) with fluorescent tags, which recognize and attach to disease markers in the sample. Then, in a 30μm x 20μm "reaction chamber," the tagged disease markers are captured, and upon them shone a focused beam of red light so they can be viewed using a portable sensor device; the amount of light detected indicates the strength of the disease marker in the sample, which helps doctors determine the next course of action.

The flow takes about 15secs, "several times faster than traditional tests," IBM notes, and can be adjusted up to several minutes for reading more complex disease markers. The test could, for instance, be applied immediately after a myocardial infarction (heart attack) to help doctors more quickly take a course of action, and help predict patient survival rate.

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Layout of the 1cm×5cm microfluidic chip. The sample is pipetted onto the chip area and pushed through the mesh structure at a regular flow rate (a) by capillary forces created by a pump (d); then through serpentine tunnels (b) to prevent clogging and air bubble formation, and where antibodies have been deposited to recognize and attach to the sample; and then led into a "reaction chamber" (c) to be examined.

From the paper abstract:

The microfluidic elements comprise a sample collector, delay valves, flow resistors, a deposition zone for dAbs, a reaction chamber sealed with a polydimethylsiloxane (PDMS) substrate, and a capillary pump and vents. Parameters for depositing 3.6nL of a solution of dAb on the chip using an inkjet are optimized and the PDMS substrate is patterned with analytes, which provide a positive control, and cAbs. Various storage conditions of the patterned PDMS are investigated for up to 6 months revealing that storage with a desiccant preserved at least 51% of the activity of the cAbs. C-reactive protein (CRP), a general inflammation and cardiac marker, is detected using this one-step chip using only 5μL of human serum by measuring fluorescent signals from 30 × 100μm2 areas of the PDMS substrate in the wet reaction chamber. The one-step chip can detect CRP at a concentration of 10ng mL-1 in less than 3min and below 1ng mL-1 within 14min.


(Lab on a Chip also has posted a movie describing the process.)

The test "is portable, fast, and requires a very small volume of sample," according to Emmanuel Delamarche, scientist at IBM Research-Zurich. Its small size lends to various formfactors such as credit cards, pens, or "something similar to a pregnancy test," and with its speed "doctors […] can make informed and accurate decisions right at the time they need them most to save lives." Aside from disease diagnosis, potential applications include testing for chemical and bio hazards.

"This microfluidic chip is the next step in the evolution of point of care devices," stated Thierry Leclipteux, CEO/chief science officer of Coris BioConcept, a biotech company developing rapid tests for diagnosing enteric and respiratory pathogens.

November 17, 2009–Cornell University’s Center for Advanced Computing (CAC), in partnership with Purdue University, has received a National Science Foundation (NSF) award to deploy The MathWorks MATLAB on the TeraGrid as an experimental computing resource. 

MATLAB, the language of technical computing, is a programming environment for algorithm development, data analysis, visualization, and numeric computation. The TeraGrid is an NSF-sponsored open scientific discovery infrastructure that unites people, resources, and services to enable discovery in US science and engineering.

Specifically, the project is designed to provide a parallel MATLAB engine for Science Gateways, such as nanoHUB.org, a resource for research, education and collaboration in nanotechnology created by the NSF-funded Network for Computational Nanotechnology. Science Gateway users will access discipline-specific Web portals, and through simulation inputs via a Web form launch MATLAB simulations and get timely results without knowledge of the underlying software or hardware infrastructure. This will allow nanotech researchers to leverage the TeraGrid as research tool without first overcoming a platform-specific learning curve.

This initiative will provide seamless parallel MATLAB computational services running on Windows HPC Server 2008 to remote desktop and Science Gateway users with complex analytic and fast simulation requirements. MATLAB is an important data analysis tool for many TeraGrid users and, as a parallel resource, it has the potential to expand the high performance computing user community.

“MATLAB on the TeraGrid will be made available in its initial configuration as a 512-core experimental computing resource to researchers with TeraGrid certificates and through Science Gateways, such as nanoHUB.org,” says Gerhard Klimeck, director of the Network for Computational Nanotechnology at Purdue University, who is co-PI on the project along with Michael McLennan, a senior research scientist at Purdue.

“nanoHUB users will benefit from this new TeraGrid resource through a transparent and instantaneous access for several applications,” added McLennan. Researchers will connect from remote desktops running MATLAB Parallel Computing Toolbox to the TeraGrid resource running MATLAB Distributed Computing Server. Researchers with Microsoft Windows, Apple Macintosh, or Linux-based clients will be able to use the same utility cluster at Cornell. 

“MATLAB on the TeraGrid will help enable a broader class of researchers who are well-versed in MATLAB to reduce the time to solution in a scalable manner without having to become parallel programming experts,” saiys Cornell University’s senior vice provost for research Robert Buhrman. “It will serve as a complementary experimental component to NSF’s large-scale eXtreme Digital vision and TeraGrid Science Gateways, and be a valuable tool to researchers focused on solving complex problems in the environment, health care, and many other science and engineering disciplines.”

November 16, 2009–Industry executives attending the annual MEMS Executive Congress last week in Sonoma, CA were buoyed by optimistic forecasts for MEMS devices, such as accelerometers and multi-axis gyros—increasingly used in mobile handsets and video games. Presentations and panel discussions included leading innovators in automotive, bio/medical, consumer electronics, mobile communications and energy.

Karen Lightman, managing director of MEMS Industry Group, the event’s host organization, said record-breaking attendance was, “In part it’s because we are experiencing a technology convergence in MEMS: sensors made for automobiles—extremely complex systems requiring the highest levels of safety and reliability—are being used for healthcare devices, such as heart monitors and 3D motion tracking."

Lightman added, "MEMS-based energy harvesters are being utilized in consumer and industrial systems, and they may one day be used in more energy-efficient, even all-electric, automobiles. And, with MEMS sensors opening up greater data collection, we will one day see things we haven’t even imagined in applications such as mobile phones.”

Highlights of the Congress included:

* Keynote by Dr. Shoichi Narahashi, executive research engineer, NTT DOCOMO Research Laboratories, on the cause-effect relationship between burgeoning multimedia services and requirements for future mobile terminals;

* Keynote by Dr. Mauro Ferrari on applications of nanotechnology in cancer detection and treatment, regenerative medicine, cardiovascular medicine and infectious diseases;

* An Automotive Panel debating the criticality of MEMS in controlling safety, efficiency and emissions—and predicting the eventual winner between hybrid-electric Vs all-electric vehicles;

* A Bio/medical Panel exhorting MEMS device makers to help them leverage sensors already proven for safety and reliability in automotive for a host of healthcare applications;

* An Energy Panel on the importance of MEMS in energy harvesting, especially in infrastructure installations in which cost reductions are paramount;

* A Consumer Electronics Panel citing the most important factor for MEMS in CE apps: it’s all about the cost.

* A Market Analyst Panel in which experts assessed the state of MEMS in 2009 and forecast emergent and resurgent growth areas in 2010 and beyond.

Next year’s MEMS Executive Congress will be held November 3-5, 2010 at the InterContinental Montelucia in Scottsdale, AZ. For more information, visit  www.memscongress.com

November 13, 2009–ClassOne Equipment, Inc., a Decatur, GA supplier of refurbished equipment for the semiconductor and nanotechnology markets, says it is making an aggressive push into the KLA-Tencor marketplace. The company, which focuses on wafer fabrication and metrology equipment, has opened a Silicon Valley office and hired former KLA-Tencor executive Fred Kelley to direct the business push.

 

Recently, Dean Freeman of technology market research firm Gartner Dataquest predicted that the refurbished semiconductor equipment market will spike dramatically in 2010, rising 33% over 2009 figures.

 

"The time is right to aggressively expand our KLA-Tencor business," commented Byron Exarcos, president of ClassOne Equipment. "Having spent his entire 28-year career at KLA-Tencor, including several years as business development manager of K-T Certified [KLA-Tencor’s business division for purchasing, refurbishing and selling used semiconductor inspection equipment], Fred has an intimate knowledge of not only the equipment, but also the market, the customers, and the sales cycles. Who better in the world is there to lead this effort for us?"

 

ClassOne says Kelley will head US and Asia sales from its new Silicon Valley office.

November 12, 2009–ITRI (Industrial Technology Research Institute), Taiwan’s largest high-tech research and development institution, has introduced STOBA (self-terminated oligomers with hyper-branched architecture), which it says is the first nano-based material technology to enhance the safety of lithium-ion (Li-ion) batteries.

Li-ion batteries, the power source for many consumer electronic devices, including cell phones, laptops, MP3 players, cameras, and hybrid and electric cars, are often the most unstable electronic component, as they are susceptible to overheating, which can cause fires and explosions.

By integrating a nano-grade polymer, which forms a protective film (much like a nano-grade fuse) into the Li-ion battery, a locking effect is generated when the battery encounters excessive heat, external impact, or piercing, and interrupts the electrical and chemical action, thereby preventing explosions.

ITRI says STOBA has passed mandatory shorting and piercing experiments conducted in 2008 and 2009 by battery manufacturers in Japan and Taiwan. The intensive nail penetration and impact tests, ITRI claims, confirmed STOBA’s effectiveness in preventing internal shorting and overheating in Li-ion batteries.

Besides its safety features, STOBA also is designed to extend the life of the Li-ion battery by about 20%, or an additional two years, due to the nano-grade STOBA film that stabilizes the electrode material at high temperatures (55 degrees Celsius).

Led by Dr. Alex Peng, senior research scientist and deputy general director at ITRI’s Material and Chemical Research Laboratories (MCL), R&D of STOBA began in 2004. After years of repeated experiments and adjustments, Peng and his team discovered the nano-grade STOBA material technology. The researchers found that the material’s heat-resistant, fair bonding and flexible qualities allow Li-ion batteries to gain redundancy time and reach twelve sigma, which generates the locking mechanism when they short and generate unstable temperatures.

ITRI has applied for 29 patents for the STOBA technology in five countries — the United States, Taiwan, Korea, China and Japan.

November 11, 2009 – Researchers at NC State U. say they have developed a way to measure properties of silicon nanowires using in-situ tensile testing, to quantify the material’s elastic and fracture properties.

Their work, published in the journal Nano Letters, attempts to do a better job of determining the properties of silicon nanowires (specifically those grown using the common vapor-liquid-solid synthesis process), which tantalizingly offer much higher surface-to-volume ratio vs. "bulk" silicon used ubiquitously in electronic devices. Specifically, they chose to "determine how much abuse these silicon nanowires can take" — how much they deform (warp/stretch until breakage), how much force they can absorb before cracking/fracturing, etc., according to project lead researcher Yong Zhu, assistant professor of mechanical engineering at NC State.

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Silicon nanowires used in in-situ scanning electron microscopy mechanical testing. (Credit: North Carolina State University)

In-situ tensile testing inside a scanning electron microscope, utilizing a nanomanipulator as the actuator and a microcantilever used as the load sensor, enabled "real-time observation of nanowire deformation and fracture, while simultaneously providing quantitative stress and strain data," noted Qingquan Qin, paper co-author and NC State Ph.D student, adding that the "very efficient" process can test "a large number of specimens […] within a reasonable amount of time."

Their results: While "bulk" silicon is brittle and can’t be stretched or warped very much without breaking, silicon nanowires were able to show far more resilience and sustained "much larger" deformation. Also, as the nanowires get smaller they also show increased fracture strength and decreased elastic modulus. From the Nano Letters abstract:

The Young’s modulus decreased while the fracture strength increased up to over 12 GPa, as the nanowire diameter decreased. The fracture strength also increased with the decrease of the side surface area; the increase rate for the chemically synthesized silicon nanowires was found to be much higher than that for the microfabricated silicon thin films. Repeated loading and unloading during tensile tests demonstrated that the nanowires are linear elastic until fracture without appreciable plasticity.

Such properties "are essential to the design and reliability of novel silicon nanodevices," pointed out Zhu. The work provides a better understanding of size effects on mechanical properties of nanostructures, as well as giving nanodevice designers more options in what they can build, e.g. sensors, electronics, and solar cells.

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SEM images of the Si nanowire with 60nm diameter before (a) and after (b) tension test, showing that the carbon deposition clamp was strong enough for testing Si nanowires with diameters up to 60nm without sliding. (Source: Nano Letters)

November 11, 2009 – Feats of dexterity, strength, and speed — on a microscale with robots. The National Institute of Standards and Technology (NIST) is opening invitations for participants in the 2010 Mobile Microrobotics Challenge. The event will be part of the IEEE’s International Conference on Robotics and Automation in May 2010 in Anchorage, AK.

Like NIST’s "nanosoccer" events held during past RoboCup competitions, these new microbot games offer several tests of teams’ engineering prowess: a 2mm dash, a microassembly task, and a "freestyle" participant-chosen task emphasizing reliability, autonomy, power management, and task complexity. The goal is to emphasize agility, maneuverability, response to computer control, and ability to move objects — abilities expected to be crucial for future industrial microbots in fields such as microsurgery or electronic device component manufacturing. At the same time, the games also will provide a showcase for what can be achieved in fabricating microelectromechanical system (MEMS) devices.

Proposed microbot participants will be operated by remote control and move in response to changing magnetic fields or electrical signals transmitted across a microchip "playing field." Sizes can range from tens to a few hundred micrometers, but mass is strictly limited to "a few nanograms." Manufacturing materials include, but are not limited to, aluminum, nickel, gold, silicon, and chromium.

Proposals are due to NIST by Dec. 31, 2009, either by e-mail ([email protected]) or snail-mail (NIST Microrobotics Challenge 2010, c/o Craig McGray, NIST, 100 Bureau Dr., MS 8120, Gaithersburg, MD 20899-8120), and must include the following: a roster of team contributors, contact information, facilities available for fabrication, operation, and characterization of microrobots, and overviews of the microrobot design, intended capabilities, and fabrication process(es) used.

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A microrobot (300μm) used at the RoboCup 2009 nanosoccer competition from Switzerland’s ETH Zurich, compared in size to the head of a fruit fly. (Credit: ETH Zurich, NIST)


November 10, 2009 – Researchers from the US and Israel say they have figured out how to make pure carbon nanotube (CNT) fibers at an industrial scale, based on "tried-and-true" processes from the chemical industry for producing polymer fibers.

The work, detailed in the journal Nature Nanotechnology, involved 18 researchers from Rice U.’s Richard E. Smalley Institute for Nanoscale Science and Technology (the late Smalley is actually listed as a co-author), the U. of Pennsylvania, and the Technion-Israel Institute of Technology. It builds on work done in 2003 to dissolve large amounts of pure CNTs in strong acidic solvents, finding the CNTs in such solutions can self-align to form liquid crystals, which could then be spun into monafilament fibers, establishing "an industrially relevant process for nanotubes that was analogous to the methods used to create Kevlar from rodlike polymers, except for the acid not being a true solvent," said Wade Adams, director of the Smalley Institute and co-author of the new paper.

The new work focuses on identifying what Adams calls "a true solvent" for CNTs: chlorosulfonic acid, in which CNTs were seen to "dissolv[e] spontaneously," proved by direct imaging of vitrified fast-frozen acid solutions, according to paper co-author Matteo Pasquali, Rice professor in chemical and biomolecular engineering and in chemistry. Studying how CNTs behave in acids, with the background knowledge of polymers and rodlike colloids, the Rice team came up with experimental techniques to examine the results and describe solutions of rods; Technion’s team developed the methodology to produce high-res images of the CNTs dispersed in the acid using electron microscopy at cryogenic temperatures.

What’s so important about devising a "true solvent" for CNTs? "Plastics is a $300B industry because of the massive throughput that’s possible with fluid processing," said Pasquali, noting that "polymers can be melted or dissolved and processed as fluids by the train-car load. Processing nanotubes as fluids opens up all of the fluid-processing technology that has been developed for polymers."

by Debra Vogler, senior technical editor, Small Times

November 9, 2009 – HP recently announced an inertial sensing technology that enables the development of digital microelectromechanical systems (MEMS) accelerometers that are up to 1,000× more sensitive than high-volume products currently available. According to David Erickson, engineering manager in HP’s technology development organization, Imaging and Printing Group, the new sensors based on this technology can achieve noise density performance in the sub-100 nano-g/square root Hz range to enable dramatic improvements in data quality. The MEMS device can be customized with single or multiple axes per chip to meet individual system requirements; its dynamic range is >130dB with a bandwidth of 0-250Hz that is extendible to 10kHz.

HP views the current inertial sensing landscape as comprising consumer devices (i.e., low-performance/low-cost) and aircraft/navigation applications (i.e., high-performance, high-resolution, expensive, and power-hungry), according to Erickson. "What we are disclosing bridges the gap, bringing together the very high performance with the cost, size, and power you could expect from a MEMS device," he said.

One key to the inertial MEMS sensor technology is a design that uses a 3-wafer (single crystal silicon) construction as opposed to silicon-on-insulator (SOI)  (see figure) — this enables temperature stability of the device, which plays directly into its low-noise sensitivity, Erickson told Small Times. Additionally, a large proof mass and the electrode design, which features constant gap sensing surface electrodes, are significant contributors to the performance. Specifically, device performance is enabled by increasing the area of the electrodes and decreasing the gap distance.

Most inertial sensors have a proof mass on springs that moves when the device moves (sensing the position of the mass with capacitive electrodes is the generally accepted approach), Erickson explained, but HP extended that principle by using a proof mass that is 1000× more massive than traditional MEMS devices. That translates into a three orders-of-magnitude improvement in noise floor performance, he said, and combined with HP’s electrode design, results in a device possessing unique features: "a much lower noise floor and a much broader dynamic range and much more thermally stable," he said. The proof mass is suspended by very high-aspect-ratio silicon springs that provide the required stiffness; very deep etches are required to make them. Though HP primarily uses standard etchers, the company has developed proprietary processes, Erickson noted.

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Developing the manufacturing processes to release such a large proof mass was also a difficult challenge, according to Erickson: "It’s thick and big, and most MEMS processes don’t deal well with removing a lot of material." He said the innovation came about because the company was looking for ways to construct a micromover — i.e., a way to very precisely move a piece of silicon in a MEMS device. Because a MEMS accelerometer is akin to a motor in reverse, when the researchers built a motor with parallel electrodes to move the proof mass to a precise location, "that insight from the motor problem was applied to accelerometers […] We realized you could sense very precisely a proof mass motion with a similar electrode structure, and then we went to work on a large proof mass. So we came at it from a different angle than most sensor designers are using."

Other manufacturing processes also play a major role. "We’ve been working on manufacturing processes and process capabilities that allowed us to get to much smaller gaps," Erickson told Small Times. Smaller gaps mean larger capacitance, and therefore greater the signal-to-noise ratio (S:N). The way in which the electrodes are structured, the very small gaps and the parallelism of the electrodes — all contribute to an orders of magnitude change when the proof mass moves (i.e. the S:N ratio is higher).

The company believes that its test data suggest the new devices can enable new classes of applications — for example, bridge monitoring and seismic monitoring. "We’ve done quite a bit of work looking into bridge monitoring," said Erickson. "Sensors available today are insufficient to detect vibrations at frequencies that are needed for structural analysis."

"HP envisions that sensor networks utilizing HP’s new inertial sensing technology will create a new paradigm in bridge maintenance and safety," Grant Pease, business development manager, told Small Times. "The technology will provide higher resolution to measure vibration modes in a bridge, which in turn provides a better understanding of the structural health and usage. The inherent low power usage of the technology enables wireless operation over an extended period of time allowing for cost-effective implementation and use."  (For additional discussion of bridge and infrastructure monitoring, see Small Times‘ interview with Michael O’Halloran of CH2M Hill: CH2M Hill, HP eye progress in infrastructure monitoring.)

The sensing technology is a key enabler of HP’s vision for a new information ecosystem, the Central Nervous System for the Earth (CeNSE). Integrating the devices within a complete system that encompasses numerous sensor types, networks, storage, computation, and software solutions enables a new level of awareness that facilitates communication between objects and people.