Tag Archives: nano

Scientists invent 1.2nm molecular gear

Scientists from A*STAR’s Institute of Materials Research and Engineering (IMRE), led by Professor Christian Joachim, have scored a breakthrough in nanotechnology by becoming the first in the world to invent a molecular gear of the size of 1.2nm whose rotation can be deliberately controlled. This achievement marks a radical shift in the scientific progress of molecular machines and is published in Nature Materials, one of the most prestigious journals in materials science.

Said Prof Joachim, “Making a gear the size of a few atoms is one thing, but being able to deliberately control its motions and actions is something else altogether. What we’ve done at IMRE is to create a truly complete working gear that will be the fundamental piece in creating more complex molecular machines that are no bigger than a grain of sand.”

Prof Joachim and his team discovered that the way to successfully control the rotation of a single-molecule gear is via the optimization of molecular design, molecular manipulation and surface atomic chemistry. This was a breakthrough because before the team’s discovery, motions of molecular rotors and gears were random and typically consisted of a mix of rotation and lateral displacement. The scientists at IMRE solved this scientific conundrum by proving that the rotation of the molecule-gear could be wellcontrolled by manipulating the electrical connection between the molecule and the tip of a Scanning Tunnelling Microscope while it was pinned on an atom axis.

Roll-Up Solar Panels

Xunlight, a startup in Toledo, Ohio, has developed a way to make large, flexible solar panels. It has developed a roll-to-roll manufacturing technique that forms thin-film amorphous silicon solar cells on thin sheets of stainless steel. Each solar module is about one meter wide and five and a half meters long.

As opposed to conventional silicon solar panels, which are bulky and rigid, these lightweight, flexible sheets could easily be integrated into roofs and building facades or on vehicles. Such systems could be more attractive than conventional solar panels and be incorporated more easily into irregular roof designs. They could also be rolled up and carried in a backpack, says the company’s cofounder and president, Xunming Deng. “You could take it with you and charge your laptop battery,” he says.

Amorphous silicon thin-film solar cells can be cheaper than conventional crystalline cells because they use a fraction of the material: the cells are 1 micrometer thick, as opposed to the 150-to-200-micrometer-thick silicon layers in crystalline solar cells. But they’re also notoriously inefficient. To boost their efficiency, Xunlight made triple-junction cells, which use three different materials–amorphous silicon, amorphous silicon germanium, and nanocrystalline silicon–each of which is tuned to capture the energy in different parts of the solar spectrum. (Conventional solar cells use one primary material, which only captures one part of the spectrum efficiently.)


New Nano-Beads Laced With Venom Slow Cancer Spread

They’re not quite as efficient as Borg technology. But new “nanoprobes” made by combining scorpion venom with tiny metal beads are giving the fight against cancer a big performance boost.

Previous work had shown that chlorotoxin, a chemical derived from the giant Israeli scorpion, affects a protein on the outside of brain tumor cells called MMP-2. This protein is thought to help the cancer cells spread.

Chlorotoxin binds to MMP-2 like a key fitting in a lock. When the chemical latches on, both it and the protein get sucked into the cell.

Fewer MMP-2 sites on a cell surface make it harder for the cancer cell to travel to new regions in the brain.

In a new study, scientists chemically bonded iron oxide nanoparticles with a lab-made version of chlorotoxin to create tiny nanoprobes, each carrying up to 20 chlorotoxin molecules.

“So when a tumor cell uptakes a single nanoparticle, it is absorbing quite a few chlorotoxin molecules at once,” said study leader Miqin Zhang of the University of Washington.

The researchers found that the nanoprobes can halt the spread of brain tumors in mice by 98 percent, compared to 45 percent with the scorpion venom alone.

A company called Transmolecular Inc. is already testing chlorotoxin by itself as a brain cancer therapy for humans.


‘Instant on’ computing

Materials researchers say rebooting soon may be a thing of the past

The ferroelectric materials found in today’s “smart cards” used in subway, ATM and fuel cards soon may eliminate the time-consuming booting and rebooting of computer operating systems by providing an “instant-on” capability as well as preventing losses from power outages.

Researchers supported by a National Science Foundation (NSF) nanoscale interdisciplinary research team award and three Materials Research Science and Engineering Centers at Cornell University, Penn State University and Northwestern University recently added ferroelectric capability to material used in common computer transistors, a feat scientists tried to achieve for more than half a century. They reported their findings in the April 17 journal Science.

Ferroelectric materials provide low-power, high-efficiency electronic memory. Smart cards use the technology to instantly reveal and update stored information when waved before a reader. A computer with this capability could instantly provide information and other data to the user.

Researchers led by Cornell University materials scientist Darrell Schlom took strontium titanate, a normally non-ferroelectric variant of the ferroelectric material used in smart cards, and deposited it on silicon–the principal component of most semiconductors and integrated circuits–in such a way that the silicon squeezed it into a ferroelectric state.

“It’s great to see fundamental research on ordered layering of materials, or epitaxial growth, under strained conditions pay off in such a practical manner, particularly as it relates to ultra-thin ferroelectrics” said Lynnette Madsen, the NSF program director responsible for the Nanoscale Interdisciplinary Research Team award.

The result could pave the way for a next-generation of memory devices that are lower power, higher speed and more convenient to use. For everyday computer users, it could mean no more waiting for the operating system to come online or to access memory slowly from the hard drive.


Nanocapacitors with Big-Energy Storage

The ultimate electronic energy-storage device would store plenty of energy but also charge up rapidly and provide powerful bursts when needed. Sadly, today’s devices can only do one or the other: capacitors provide high power, while batteries offer high storage.

Now researchers at the University of Maryland have developed a kind of capacitor that brings these qualities together. The research is in its early stages, and the device will have to be scaled up to be practical, but initial results show that it can store 100 times more energy than previous devices of its kind. Ultimately, such devices could store surges of energy from renewable sources, like wind, and feed that energy to the electrical grid when needed. They could also power electric cars that recharge in the amount of time that it takes to fill a gas tank, instead of the six to eight hours that it takes them to recharge today.

There are many different kinds of batteries and capacitors, but in general, batteries can store large amounts of energy yet tend to charge up slowly and wear out quickly. Capacitors, meanwhile, have longer lifetimes and can rapidly discharge, but they store far less total energy. Electrochemists and engineers have been working to solve this energy-storage problem by boosting batteries’ power and increasing capacitors’ storage capacity.


An artificial heart for Rs 1 lakh

It’ll be to coronary care what Nano is to cars, say scientists at Indian Institute of Technology, Kharagpur, who have devised an artificial heart that could save lives for just Rs 1 lakh.

The research team says trials of the prototype lab—constructed heart have been successful on small animals and the gadget is being perfected on goats. The institute has applied for permission to conduct human trials.

The Total Artificial Heart (TAH) — said to be the first such in the country — has been developed by a team of scientists at IIT-Kgp’s school of medical science and technology.

After four years of painstaking research, the scientists say their creation is better and far more affordable than the first artificial heart developed in the US, which showed a “high rate failure” and at Rs 30 lakh, beyond the reach of the common man.

The inventors hope to fit the heart into an ailing patient

within a few months, once permissions from the Indian Council of Medical Research come through. The unique 13—chamber heart is working fine in small animals, said a member of the team. Human tests are to be conducted at Medical College and Hospital (MCH), Kolkata.
Senior cardiac surgeons — Madhusudan Pal, Bhaskar Ukil, Tarun Saha and Kalishankar Das from MCH and Rajiv Narang of AIIMS, Delhi — will conduct the human trials.


More Efficient Solar Cells Thanks To CNT Films That Transmit Infrared Light

A thin film of carbon nanotubes is probably the most revolutionary material developed in the past twenty years and according to the scientists they haven’t “used” the material at its full potential and there is still a long way to go. Carbon nanotubes are useful in electronic displays, solar cells, and at other devices, but you should know that CNT thin films were used with light in the visible range. “Just in case” the scientists decided to explore their properties in infrared, and their results were very surprising.

The team of researchers from the University of California, Los Angeles, tested single-walled carbon thin films in infrared and they noticed that they have the ability to transmit infrared waves. The infrared properties of the optically-transparent and electrically-conductive CNT thin films were investigated by physicists Liangbing Hu, David Hecht, and George Grüner from UCLA.

“This is the first time that the infrared properties of conductive CNT films are fully studied through measurement and calculations,” said Hu, co-author at the study.


Knowing when to fold

Folding paper into shapes such as a crane or a butterfly is challenging enough for most people. Now imagine trying to fold something that’s about a hundred times thinner than a human hair and then putting it to use as an electronic device.

A team of researchers led by George Barbastathis, associate professor of mechanical engineering, is developing the basic principles of “nano-origami,” a new technique that allows engineers to fold nanoscale materials into simple 3-D structures. The tiny folded materials could be used as motors and capacitors, potentially leading to better computer memory storage, faster microprocessors and new nanophotonic devices.

Traditional micro- and nano-fabrication techniques such as X-ray lithography and nano-imprinting work beautifully for two-dimensional structures, and are commonly used to build microprocessors and other micro-electrical-mechanical (MEMS) devices. However, they cannot create 3-D structures.


Nanoscale Electronic Devices Could Soon Become A Reality

The tendency in electronic devices is all about getting smaller and smaller and smaller. It’s just the way these things need to be. However, they also have to be very efficient and we have nanotechnology and carbon nanotubes to make them like this. In order to develop smaller and more efficient electronics, scientists want to develop the next generation of devices based on carbon nanotubes using a technique called “chemical vapor deposition”, but it’s very hard to manipulate these structures and to bring them to a useful state.

A new vision is needed to complete the next-gen electronics and thanks to a breakthrough from scientists at the University of Nebraska-Lincoln, our future devices could be built from carbon nanotubes. The team of scientists led by professor Yongfeng Lu and postdoctoral researcher Yunshen Zhou, used a technique based on the so-called “optical near-field effects” and they managed to control the growth of carbon nanotubes. The researchers linked individually self-aligned carbon nanotubes with sharp-tipped electrodes, a process which is very different from previous techniques where the carbon nanotubes were manipulated after growth.

“With our method, there’s no requirement for expensive instrumentation and no requirement for tedious processes. It’s a one-step process. We call it ’self-aligning growth.’ The carbon nanotubes ‘know’ where to start growth. In previous efforts, they could only manipulate carbon nanotubes one piece at a time, so they had to align the carbon nanotubes one by one. For our approach using optical near-field effects, all locations with sharp tips can accommodate carbon nanotube growth. That means we can make multiple carbon nanotubes at a time and all of them will be self-aligned,” said professor Lu.


FDA Allows Brain Implants for Obsessions

By manipulating the magnetization of a liquid solution, the researchers have for the first time coaxed magnetic and non-magnetic materials to form intricate nano-structures. The resulting structures can be “fixed,” meaning they can be permanently linked together. This raises the possibility of using these structures as basic building blocks for such diverse applications as advanced optics, cloaking devices, data storage and bioengineering.

Changing the levels of magnetization of the fluid controls how the particles are attracted to or repelled by each other. By appropriately tuning these interactions, the magnetic and non-magnetic particles form around each other much like a snowflake forms around a microscopic dust particle.

“We have demonstrated that subtle changes in the magnetization of a fluid can create an environment where a mixture of different particles will self-assemble into complex superstructures,” said Randall Erb, fourth-year graduate student. He performed these experiments in conjunction with another graduate student Hui Son, in the laboratory of Benjamin Yellen, assistant professor of mechanical engineering and materials science and lead member of the research team.