Friday, August 27, 2010

This week in nanotechnology - August 27, 2010

Scientists and engineers seek to meet three goals in the production of biofuels from non-edible sources such as microalgae: efficiency, economical production and ecological sustainability. Syracuse University researchers have uncovered a process that is a promising step toward accomplishing these three goals. They have discovered a method to make algae, which can be used in the production of biofuels, grow faster by manipulating light particles through the use of nanobiotechnology. By creating accelerated photosynthesis, algae will grow faster with minimal change in the ecological resources required.

Just as cilia lining the lungs help keep passages clear by moving particles along the tips of the tiny hair-structures, man-made miniscule bristles known as nano-brushes can help reduce friction along surfaces at the molecular level, among other things. In their latest series of experiments, Duke University engineers have developed a novel approach to synthesize these nano-brushes, which could improve their versatility in the future. These polymer brushes are currently being used in biologic sensors and microscopic devices, such as microcantilevers, and they will play an important role in the future drive to miniaturization, the researchers said.

In a step toward more efficient, smaller and higher-definition display screens, a University of Michigan professor has developed a new type of color filter made of nano-thin sheets of metal with precisely spaced gratings. The gratings, sliced into metal-dielectric-metal stacks, act as resonators. They trap and transmit light of a particular color, or wavelength. Simply by changing the space between the slits, the researchers can generate different colors. Through nanostructuring, they can render white light any color.

An optical microscopy image of seven color filters illuminated by white microscope light

An optical microscopy image of seven color filters illuminated by white microscope light.

If a drug can be guided to the right place in the body, the treatment is more effective and there are fewer side-effects. Researchers at Lund University in Sweden have now developed magnetic nanoparticles that can be directed to metallic implants such as artificial knee joints, hip joints and stents in the coronary arteries. The team has shown that the principle works in animal experiments. They have succeeded in attaching a clot-dissolving drug to the nanoparticles and, with the help of magnets, have directed the particles to a blood clot in a stent in the heart to dissolve it. Thus the nanoparticles have been able to stop an incipient heart attack.

Researchers from North Carolina State University have developed extremely small microneedles that can be used to deliver medically-relevant nanoscale dyes called quantum dots into skin – an advance that opens the door to new techniques for diagnosing and treating a variety of medical conditions, including skin cancer.

Using a cutting edge nanotechnology, researchers at MIT have created a robotic prototype that could autonomously navigate the surface of the ocean to collect surface oil and process it on site. The system, called Seaswarm, is a fleet of vehicles that may make cleaning up future oil spills both less expensive and more efficient than current skimming methods.

NanoEngineers at the University of California, San Diego are designing new types of lithium-ion (Li-ion) batteries that could be used in a variety of NASA space exploration projects – and in a wide range of transportation and consumer applications. The nearly $600,000 program builds upon expertise in the UC San Diego Department of NanoEngineering in modeling new nanocomposite structures for next generation electrode materials, and NEI's capability to reproducibly synthesize electrode materials at the nanoscale.

Friday, August 20, 2010

This week in nanotechnology - August 20, 2010

Researchers demonstrate that non-viral gene therapy can delay the onset of some forms of eye disease and preserve vision. The team developed nanoparticles to deliver therapeutic genes to the retina and found that treated mice temporarily retained more eyesight than controls.

Nanocorrosion causes implants to fail. Extra-hard coatings made from diamond-like carbon (DLC) extend the operating lifetime of tools and components. In artificial joints, however, these coatings often fail because they detach. Empa researchers found out why – and developed methods to both make the interface between the DLC layer and the metal underneath corrosion-resistant and to predict the lifetime of the implants.

Ultra- or supercapacitors are emerging as a key enabling storage technology for use in fuel-efficient transport as well as in renewable energy. Engineers hope that supercapacitors can bridge the gap between batteries and electrolytic capacitors, but contemporary devices have a lower specific energy than Li-ion batteries and are orders of magnitude slower than electrolytic capacitors. Researchers have now shown that by moving from porous carbon with a network of pores inside particles as electrode material to exposed surfaces of nanostructured carbon onions of 6-7 nm diameter, it is possible to reach the discharge rate (power) of electrolytic capacitors, but with volumetric capacitance about four orders of magnitude higher.

Clinical trials using patients' own immune cells to target tumors have yielded promising results. However, this approach usually works only if the patients also receive large doses of drugs designed to help immune cells multiply rapidly, and those drugs have life-threatening side effects. Now a team of MIT engineers has devised a way to deliver the necessary drugs by smuggling them on the backs of the cells sent in to fight the tumor. That way, the drugs reach only their intended targets, greatly reducing the risk to the patient.

drug-carrying pouches attached to the surfaces of cells

Engineers have developed a way to attach drug-carrying pouches (yellow) to the surfaces of cells.

As semiconductor manufacturers build ever smaller components, circuits and chips at the nano scale become less reliable and more expensive to produce. The variability in their behavior from device to device and over their lifetimes – due to manufacturing, aging-related wear-out, and varying operating environments – is largely ignored by today's mainstream computer systems. Now a visionary team of computer scientists and electrical engineers from six universities is proposing to deal with the downside of nanoscale computer components by re-thinking and enhancing the role that software can play in a new class of computing machines that are adaptive and highly energy efficient.

Friday, August 13, 2010

This wek in nanotechnology - August 13, 2010

Scientists can detect the movements of single molecules by using fluorescent tags or by pulling them in delicate force measurements, but only for a few minutes. A new technique by Rice University researchers will allow them to track single molecules without modifying them – and it works over longer timescales.

Chemists and engineers at Harvard University have fashioned nanowires into a new type of V-shaped transistor small enough to be used for sensitive probing of the interior of cells. The new device is smaller than many viruses and about one-hundredth the width of the probes now used to take cellular measurements, which can be nearly as large as the cells themselves. Its slenderness is a marked improvement over these bulkier probes, which can damage cells upon insertion, reducing the accuracy or reliability of any data gained.

Under the microscope, the bacteria start dividing normally, two cells become four and then eight and so on. But then individual cells begin "popping," like circus balloons being struck by darts. This phenomenon, which surprised the Duke University bioengineers who captured it on video, turns out to be an example of a more generalized occurrence that must be considered by scientists creating living, synthetic circuits out of bacteria. Even when given the same orders, no two cells will behave the same. The researchers believe this accidental finding of a circuit they call "ePop" can help increase the efficiency and power of future synthetic biology circuits.

A new test for oral cancer, which a dentist could perform by simply using a brush to collect cells from a patient´s mouth, is set to be developed by researchers at the University of Sheffield and Sheffield Teaching Hospitals NHS Foundation Trust. The nano-bio-chips are disposable and slotted like a credit card into a battery-powered analyser.

Researchers at Ohio State University have demonstrated the first plastic computer memory device that utilizes the spin of electrons to read and write data. An alternative to traditional microelectronics, so-called "spintronics" could store more data in less space, process data faster, and consume less power.

Researchers have taken one more step toward understanding the unique and often unexpected properties of graphene, a two-dimensional carbon material that has attracted interest because of its potential applications in future generations of electronic devices. They describe for the first time how the orbits of electrons are distributed spatially by magnetic fields applied to layers of epitaxial graphene.

It turns out that watching paint dry might not be as boring as the old adage claims. A team led by Yale University researchers has come up with a new technique to study the mechanics of coatings as they dry and peel, and has discovered that the process is far from mundane. They present a new way to image and analyze the mechanical stress that causes colloidal coatings – those in which microscopic particles of one substance are dispersed throughout another – to peel off of surfaces.

A "smart" nanomaterial recently developed at the University of Dayton Research Institute for multi-purpose use in aircraft coatings, wind turbines and other large-scale commercial applications may also lead to a significant breakthrough in glaucoma treatment. Nicknamed "fuzzy fiber", the tailored carbon material is expected to improve the lives of glaucoma sufferers by reducing the number of medical procedures needed to treat the disease.

Friday, August 6, 2010

This week in nanotechnology - August 6, 2010

One Chicago skyline is dazzling enough. Now imagine 15,000 of them.
A Northwestern University research team has done just that -- drawing 15,000 identical skylines with tiny beams of light using an innovative nanofabrication technology called beam-pen lithography (BPL). The technology offers a means to rapidly and inexpensively make and prototype circuits, optoelectronics and medical diagnostics and promises many other applications in the electronics, photonics and life sciences industries.

Nanoparticle-coated pavement that cleans the air: The concentrations of toxic nitrogen oxide that are present in German cities regularly exceed the maximum permitted levels. That's now about to change, as innovative paving slabs that will help protect the environment are being introduced. Coated in titanium dioxide nanoparticles, they reduce the amount of nitrogen oxide in the air.

A newly discovered nanomaterial – silicon nanoneedles with modulated porosity – could improve healthcare devices by increasing energy storage, help realize implantable microchips or make better drugs. The nanoporous needles are flexible, semiconductors, biodegradable and have a surface one hundred times larger that of solid nanowires. These unique properties of the nanowires will provide a higher energy density when used as large surface anodes in lithium batteries, constitute the active elements of bioresorbable, flexible microchips for subcutaneous implants or protect drugs while in the body and release them in a controlled manner to improve their therapeutic effect.

atomically-thin graphene nanopores

Left: A side view of a forest of bicolor nanoneedles. A central low porosity segment is green and two siding high porosity segments are red. An ultrathin porous wire crosses the picture sideways, in yellow. Middle: Bicolor nanoneedles seen from an angle. The high porosity segment is red and low porosity segment is green. The grass-like flexibility of the nanowires allows the tips to join. Right: A forest of evenly spaced cylindrical nanoneedles. The diameter is 100nm and allows piercing of cell membrane without harming the cells.

In an innovation critical to improved DNA sequencing, a markedly slower transmission of DNA through nanopores has been achieved. Solid-state nanopores sculpted from silicon dioxide are generally straight. They are used as sensors to detect and characterize DNA, RNA and proteins. But these materials shoot through such holes so rapidly that sequencing the DNA passing through them is a problem. Researchers now report using self-assembly techniques to fabricate equally tiny but kinked nanopores which achieve a fivefold slowdown in the voltage-driven translocation speeds critically needed in DNA sequencing.

For the first time ever, scientists watch an atom's electrons moving in real time. The researchers used ultrashort flashes of laser light to directly observe the movement of an atom's outer electrons for the first time. Through a process called attosecond absorption spectroscopy, researchers were able to time the oscillations between simultaneously produced quantum states of valence electrons with great precision. These oscillations drive electron motion.

While most most polymer solar cells are manufactured through a spin-coating process – a technology very useful for fabricating very thin and homogeneous film and for controlling the film thickness – spin-coating has several drawbacks with regard to its application to mass production: scale-up is problematic and the process is not continuous; it is impossible to fabricate flexible devices; the process is not only expensive and wasteful but the cost increases exponentially as the substrate size increases. To overcome these problems, researchers have now introduced a highly efficient polymer solar cell fabrication method by a novel coating process – roller painting.