Multicolor Quantum Dots Aid in Cancer Biopsy Diagnosis
Reed-Sternberg cells can be distinguished by their red outline, blue and white internal staining, and their lack of green staining. (Credit: Emory)
The tunable fluorescent nanoparticles known as quantum dots make ideal tools for distinguishing and identifying rare cancer cells in tissue biopsies, Emory and Georgia Tech scientists have demonstrated. The researchers described how multicolor quantum dots linked to antibodies can distinguish the Reed-Sternberg cells that are characteristic of Hodgkin's lymphoma. "Our multicolor quantum dot staining method provides rapid detection and identification of rare malignant cells from heterogenous tissue specimens," says senior author Shuming Nie, PhD, the Wallace H. Coulter distinguished professor in the Coulter department of biomedical engineering at Georgia Tech and Emory University. "The clinical utility is not limited to Hodgkin's lymphoma but potentially could be extended to detect cancer stem cells, tumor-associated macrophages and other rare cell types." Quantum dots are nanometer-sized semiconductor crystals that have unique chemical and physical properties due to their size and their highly compact structure. Quantum dots can be chemically linked to antibodies, which can detect molecules present on the surfaces or internal parts of cancer cells.. Find out more...
Molecules that Behave Like Robots
Researchers have created and observed a molecular robot capable of many steps, and of making decisions where to step and how long to stay. As the robot walks on the substrate, it changes each piece by cleaving off a part. If it touches a spot that has been cleaved already, it does not linger as long. The end of the track glows red and captures the robot, letting the researchers know when it has completed its walk. The robot glows green, allowing for the researchers to see it better. Credit: Zina Deretsky, National Science Foundation .
Researchers from Columbia University, Arizona State University, the University of Michigan and the California Institute of Technology (Caltech) have created and programmed robots the size of single molecule that can move independently across a nano-scale track. This development marks an important advancement in the nascent fields of molecular computing and robotics, and could someday lead to molecular robots that can fix individual cells or assemble nanotechnology products. Recent molecular robotics work has produced so-called DNA walkers, or strings of reprogrammed DNA with 'legs' that enabled them to briefly walk. Now this research team has shown these molecular robotic spiders can in fact move autonomously through a specially-created, two-dimensional landscape. The spiders acted in rudimentary robotic ways, showing they are capable of starting motion, walking for awhile, turning, and stopping. In addition to be incredibly small--about 4 nanometers in diameter--the walkers are also move slowly, covering 100 nanometers in times ranging 30 minutes to a full hour by taking approximately 100 steps. This is a significant improvement over previous DNA walkers that were capable of only about three steps. While the field of molecular robotics is still emerging, it is possible that these tiny creations may someday have important medical applications. "This work one day may lead to effective control of chronic diseases such as diabetes or cancer," says Mitra Basu, a program director at NSF responsible for the agency's support to this research.
Nano-sized Advance Toward Next Big Treatment Era in Dentistry
Dentists may use a special nano-sized film in the future to bring diseased teeth back to life rather than remove them.
Scientists are reporting an advance toward the next big treatment revolution in dentistry -- the era in which root canal therapy brings diseased teeth back to life, rather than leaving a "non-vital" or dead tooth in the mouth. They describe a first-of-its-kind, nano-sized dental film that shows early promise for achieving this long-sought goal. Nadia Benkirane-Jessel and colleagues at the Institut National de la Sante et de la Recherche Medicale in France note that root canal procedures help prevent tooth loss in millions of people each year. During the procedure, a dentist removes the painful, inflamed pulp, the soft tissue inside the diseased or injured tooth that contains nerves and blood vessels. Regenerative endodontics, the development and delivery of tissues to replace diseased or damaged dental pulp, has the potential to provide a revolutionary alternative to pulp removal. The scientists are reporting development of a multilayered, nano-sized film -- only 1/50,000th the thickness of a human hair containing a substance that could help regenerate dental pulp. Previous studies show that the substance, called alpha melanocyte stimulating hormone, or alpha-MSH, has anti-inflammatory properties. The scientists showed in laboratory tests alpha-MSH combined with a widely-used polymer produced a material that fights inflammation in dental pulp fibroblasts. Fibroblasts are the main type of cell found in dental pulp. Nano-films containing alpha-MSH also increased the number of these cells. This could help revitalize damaged teeth and reduce the need for a root canal procedure, the scientists suggest.
How Butterflies’ Wings Could Cut Bank Fraud
University of Cambridge scientists have discovered a way of mimicking the stunningly bright and beautiful colours found on the wings of tropical butterflies. The findings could have important applications in the security printing industry, helping to make bank notes and credit cards harder to forge. The striking iridescent colours displayed on beetles, butterflies and other insects have long fascinated both physicists and biologists, but mimicking nature's most colourful, eye-catching surfaces has proved elusive. This is partly because rather than relying on pigments, these colours are produced by light bouncing off microscopic structures on the insects' wings. Mathias Kolle, working with Professor Ullrich Steiner and Professor Jeremy Baumberg of the University of Cambridge, studied the Indonesian Peacock or Swallowtail butterfly (Papilio blumei), whose wing scales are composed of intricate, microscopic structures that resemble the inside of an egg carton. Because of their shape and the fact that they are made up of alternate layers of cuticle and air, these structures produce intense colours.
Using a combination of nanofabrication procedures - including self-assembly and atomic layer deposition - Kolle and his colleagues made structurally identical copies of the butterfly scales, and these copies produced the same vivid colours as the butterflies' wings. According to Kolle: "We have unlocked one of nature's secrets and combined this knowledge with state-of-the-art nanofabrication to mimic the intricate optical designs found in nature." "Although nature is better at self-assembly than we are, we have the advantage that we can use a wider variety of artificial, custom-made materials to optimise our optical structures." As well as helping scientists gain a deeper understanding of the physics behind these butterflies' colours, being able to mimic them has promising applications in security printing. "These artificial structures could be used to encrypt information in optical signatures on banknotes or other valuable items to protect them against forgery. We still need to refine our system but in future we could see structures based on butterflies wings shining from a £10 note or even our passports," he says. (Note: video above courtesy of University of Cambridge.) Find out more...
NIST Scientists Gain New Core Understanding of Nanoparticles
Schematic of a spherical magnetite nanoparticle shows the unexpected variation in magnetic moment between the particle's interior and exterior when subjected to a strong magnetic field. The core's moment (black lines in magenta region) lines up with the field's (light blue arrow), while the exterior's moment (black arrows in green region) forms at right angles to it. Credit: NIST
While attempting to solve one mystery about iron oxide-based nanoparticles, a research team working at the National Institute of Standards and Technology (NIST) stumbled upon another one. But once its implications are understood, their discovery may give nanotechnologists a new and useful tool. The nanoparticles in question are spheres of magnetite so tiny that a few thousand of them lined up would stretch a hair’s width, and they have potential uses both as the basis of better data storage systems and in biological applications such as hyperthermia treatment for cancer. A key to all these applications is a full understanding of how large numbers of the particles interact magnetically with one another across relatively large distances so that scientists can manipulate them with magnetism. The team applied a magnetic field to nanocrystals composed of 9 nm-wide particles, made by collaborators at Carnegie Mellon University. The field caused the particles to line up like iron filings on a piece of paper held above a bar magnet. But when the team looked closer using the neutron beam, what they saw revealed a level of complexity never seen before. “When the field is applied, the inner 7 nm-wide ‘core’ orients itself along the field’s north and south poles, just like large iron filings would,” says Kathryn Krycka, a researcher at the NIST Center for Neutron Research. “But the outer 1 nm ‘shell’ of each nanoparticle behaves differently. It also develops a moment, but pointed at right angles to that of the core.” In a word, bizarre. But potentially useful. The shells are not physically different than the interiors; without the magnetic field, the distinction vanishes. But once formed, the shells of nearby particles seem to heed one another: A local group of them will have their shells’ moments all lined up one way, but then another group’s shells will point elsewhere. This finding leads Krycka and her team to believe that there is more to be learned about the role that particle interaction has on determining internal, magnetic nanoparticle structure—perhaps something nanotechnologists can harness. “The effect fundamentally changes how the particles would talk to each other in a data storage setting,” Krycka says. “If we can control it—by varying their temperature, for example, as our findings suggest we can—we might be able to turn the effect on and off, which could be useful in real-world applications.” Find out more...
Spiders at the Nanoscale
The latest installment in DNA nanotechnology has arrived: A molecular nanorobot dubbed a "spider" and labeled with green dyes traverses a substrate track built upon a DNA origami scaffold. It journeys towards its red-labeled goal by cleaving the visited substrates, thus exhibiting the characteristics of an autonomously moving, behavior-based robot at the molecular scale. (Image Source: CALTECH Press Release incorporating Image Credit: Paul Michelotti)
A team of scientists from Columbia University, Arizona State University, the University of Michigan, and the California Institute of Technology (Caltech) have programmed an autonomous molecular "robot" made out of DNA to start, move, turn, and stop while following a DNA track. Shrinking robots down to the molecular scale would provide, for molecular processes, the same kinds of benefits that classical robotics and automation provide at the macroscopic scale. Molecular robots, in theory, could be programmed to sense their environment (say, the presence of disease markers on a cell), make a decision (that the cell is cancerous and needs to be neutralized), and act on that decision (deliver a cargo of cancer-killing drugs). Or, like the robots in a modern-day factory, they could be programmed to assemble complex molecular products. The power of robotics lies in the fact that once programmed, the robots can carry out their tasks autonomously, without further human intervention. Milan N. Stojanovic, a faculty member in the Division of Experimental Therapeutics at Columbia University, led the project and teamed up with Winfree and Hao Yan, professor of chemistry and biochemistry at Arizona State University and an expert in DNA nanotechnology, and with Nils G. Walter, professor of chemistry and director of the Single Molecule Analysis in Real-Time (SMART) Center at the University of Michigan in Ann Arbor, for what became a modern-day self-assembly of like-minded scientists with the complementary areas of expertise needed to tackle a tough problem. Find out more...
New ‘Nanoburrs’ Could Help Fight Heart Disease
Image Credit: MIT
Researchers at MIT and Harvard Medical School have built targeted nanoparticles that can cling to artery walls and slowly release medicine, an advance that potentially provides an alternative to drug-releasing stents in some patients with cardiovascular disease. The particles, dubbed “nanoburrs” because they are coated with tiny protein fragments that allow them to stick to target proteins, can be designed to release their drug payload over several days. The nanoburrs are targeted to a specific structure, known as the basement membrane, which lines the arterial walls and is only exposed when those walls are damaged. Therefore, the nanoburrs could be used to deliver drugs to treat atherosclerosis and other inflammatory cardiovascular diseases. They are one of the first such targeted particles that can precisely home in on damaged vascular tissue, says Omid Farokhzad, associate professor at Harvard Medical School. Farokhzad and MIT Institute Professor Robert Langer have previously developed nanoparticles that seek out and destroy tumorsThe researchers hope the particles could become a complementary approach that can be used with vascular stents, which are the standard of care for most cases of clogged and damaged arteries, or in lieu of stents in areas not well suited to them, such as near a fork in the artery. Find out more...
Smart Coating Opens Door To Safer Hip, Knee and Dental Implants
Cross-sectional transmission electron microscope image of the functionally graded smart coating with nano-silver particles distributed throughout the entire thickness of the coating. Image Credit: North Carolina State University
Researchers at North Carolina State University have developed a “smart coating” that helps surgical implants bond more closely with bone and ward off infection. When patients have hip, knee or dental replacement surgery, they run the risk of having their bodies reject the implant. But the smart coating developed at NC State mitigates that risk by fostering bone growth into the implant. The coating creates a crystalline layer next to the implant, and a mostly amorphous outer layer that touches the surrounding bone. The amorphous layer dissolves over time, releasing calcium and phosphate, which encourages bone growth. The researchers have also incorporated silver nanoparticles throughout the coating to ward off infections. Currently, implant patients are subjected to an intense regimen of antibiotics to prevent infection immediately following surgery. However, the site of the implant will always remain vulnerable to infection. But by incorporating silver into the coating, the silver particles will act as antimicrobial agents as the amorphous layer dissolves. This will not only limit the amount of antibiotics patients will need following surgery, but will provide protection from infection at the implant site for the life of the implant. Moreover, the silver is released more quickly right after surgery, when there is more risk of infection, due to the faster dissolution of the amorphous layer of the coating. Silver release will slow down while the patient is healing. Find out more... and explore other nanotechnology medical applications...
Celebrate NanoDays - March 27 - April 4, 2010
NanoDays is a U.S.-based festival of educational programs about nanoscale science and engineering and its potential impact on the future. NanoDays events are organized by participants in the Nanoscale Informal Science Education Network (NISE Net), and take place at over 200 science museums, research centers, and universities across the country. Since 2008, NanoDays celebrations across the United States have combined simple hands-on activities for young people with events exploring current research for adults. This year it is easier than ever to find a museum, university, or research organization that is hosting an event. A list of organizations participating in NanoDays 2010 has been compiled to help those interested in participating.
Rice, Korean Collaboration Produces Printable Tag that Could Replace Bar Codes
RFID tags printed through a new roll-to-roll process could replace bar codes and make checking out of a store a snap. Image Credit: Gyou-Jin Cho/Sunchon National University
Long lines at store checkouts could be history if a new technology created in part at Rice University comes to pass. Rice researchers, in collaboration with a team led by Gyou-jin Cho at Sunchon National University in Korea, have come up with an inexpensive, printable transmitter that can be invisibly embedded in packaging. It would allow a customer to walk a cart full of groceries or other goods past a scanner on the way to the car; the scanner would read all items in the cart at once, total them up and charge the customer's account while adjusting the store's inventory. More advanced versions could collect all the information about the contents of a store in an instant, letting a retailer know where every package is at any time. The technology described in the journal "IEEE Transactions on Electron Devices" is based on a carbon-nanotube-infused ink for ink-jet printers first developed in the Rice University lab of James Tour, the T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science. The ink is used to make thin-film transistors, a key element in radio-frequency identification (RFID) tags that can be printed on paper or plastic. Find out more...
Smart Polymers Perform Nano-Acrobatics
One result of the new research is that scientists will now be able to exploit the COMPcc portion of a polymer to wrap around a Vitamin D molecule in order to stimulate its tissue-regenerating power. Genetically engineered copolymers have applications in everything from artificial therapeutics, biocatalysts, scaffolds, and cells for medicine, to sustainable energy and environmental remediation. Credit: New York University
Researchers are finding remarkable ways in which bioengineered paired macromolecules can be made to self-assemble, disassemble, and more -- and then biodegrade when they’ve finished their work. The key to these macromolecules -- called block copolymers -- is their ability to self-assemble when exposed to discrete external stimuli. Self-assembly can occur as a function of temperature or pH, for example. And it is not necessarily a permanent change; it can be reversed. Genetically engineered copolymers have applications in everything from artificial therapeutics, biocatalysts, scaffolds, and cells for medicine, to sustainable energy and environmental remediation. For four years, Jin Kim Montclare and researchers at the Polytechnic Institute of New York University have been developing block copolymers from scratch using recombinant DNA and putting them through biochemical hoops. The group’s work, published recently in the journal ChemBioChem, involves block copolymers comprising elastin alternating with COMPcc. The former is a pentapeptide whose amino-acid constituents can assemble into a beta spiral structure as a function of temperature, pH, or salinity. COMPcc, which stands for “cartilage oligomeric matrix protein coil coiled,” is a pentamer arranged as five helixes that can contort into an arrangement that produces a hydrophobic core the way one might create a cylindrical cavity by stacking garden hoses on a deck -- thus the odd “coiled coil” nomenclature. COMPcc has the ability to bind small water-insoluble molecules such as Vitamin D within its hydrophobic core. The possibilities are manifold. “That central pore can potentially bind chemicals that are hard to deliver as drugs because they are normally not water soluble,” says Montclare. For example COMPcc can bind to Vitamin D, a non-dissolving molecule that happens to have profound implications for regenerative tissue and serves as a signaling hormone for the promotion of tissue differentiation into cartilage and bone. And COMPcc can “live” in a copolymer with elastin, synthetics, or other coiled coil-based materials that self-assemble into gels or more organized forms like scaffolding, which can be used for tissue regeneration. Find out more...
Rice Physicists Kill Cancer with 'Nanobubbles'
By using lasers and nanoparticles Jason Hafner, left, and Dmitri Lapotko have discovered a new technique for singling out individual diseased cells and destroying them with tiny explosions. Credit: Jeff Fitlow/Rice University
Using lasers and nanoparticles, scientists at Rice University have discovered a new technique for singling out individual diseased cells and destroying them with tiny explosions. The scientists used lasers to make "nanobubbles" by zapping gold nanoparticles inside cells. In tests on cancer cells, they found they could tune the lasers to create either small, bright bubbles that were visible but harmless or large bubbles that burst the cells. Nanobubbles are created when gold nanoparticles are struck by short laser pulses. The short-lived bubbles are very bright and can be made smaller or larger by varying the power of the laser. Because they are visible under a microscope, nanobubbles can be used to either diagnose sick cells or to track the explosions that are destroying them. In the current study, Lapotko and Rice colleague Jason Hafner, associate professor of physics and astronomy and of chemistry, tested the approach on leukemia cells and cells from head and neck cancers. They attached antibodies to the nanoparticles so they would target only the cancer cells, and they found the technique was effective at locating and killing the cancer cells. Find out more...
Watching Crystals Grow May Lead to Faster Electronic Devices
Conventional theory says when films are being formed at the atomic scale, atoms land on top of each other and form mounds or "islands" and feel an energetic "pull" from other atoms that prevents them from hopping off the island's edges and crystallizing into smooth sheets. The result is rough spots on the thin films used to produce semiconductors. Cornell University-led researchers eliminated this pull by shortening the bonds between their particles. But they still saw particles hesitate at the island's edges.
Image Credit: Rajesh Ganapathy, Sharon Gerbode, Mark Buckley, and Itai Cohen - Cornell University
The quest for faster electronic devices recently got something more than a little bump up in technological knowhow. Scientists at Cornell University, Ithaca, N.Y. discovered that the thin, smooth, crystalline sheets needed to make semiconductors, which are the foundation of modern computers, might be grown into smoother sheets by managing the random darting motions of the atomic particles that affect how the crystals grow. Led by assistant professor of physics Itai Cohen at Cornell, researchers recreated conditions of layer-by-layer crystalline growth using particles much bigger than atoms, but still small enough that they behave like atoms. Similar to using beach balls to model the behavior of sand, scientists used a solution of tiny plastic spheres 50 times smaller than a human hair to reproduce the conditions that lead to crystallization on the atomic scale. With this precise modeling, they could watch how crystalline sheets grow. Using an optical microscope, the scientists could watch exactly what their "atoms"--actually, micron-sized silica particles suspended in fluid--did as they crystallized. What's more, they were able to manipulate single particles one at a time and test conditions that lead to smooth crystal growth. The video below is sped up by a factor of about 20. Video Credit: John Savage, Rajesh Ganapathy, and Itai Cohen - Cornell University. Find out more...
Nanodragsters Hit the Street
Image Credit: Rice University
The latest work in a series of molecular machines that began with 2005's nanocar has produced what Rice University scientists James Tour and Kevin Kelly call a nanodragster for its characteristic hot-rod shape, with small wheels on a short axle in the front and large wheels on a long axle in the back. Their research is another step toward functional nanomachines that can be custom-built and set to work in microelectronics and other applications. What those wheels are made of matters most. Early nanocars rolled on simple carbon 60 molecules, aka buckyballs. But they were a drag, literally, as they would only turn on a gold surface in high heat, about 200 degrees Celsius. The Rice team found in previous research that wheels made of p-carborane, a cluster of carbon and boron atoms, operate at much lower temperatures. But they're more difficult to image with a scanning tunneling microscope because of their much weaker interaction with metallic surfaces. The key to making nanodragsters was putting p-carborane wheels in the front and buckyballs in the back, getting the advantages of both. The front wheels roll easier, while the buckyballs grip the gold roadway well enough to be imaged. And the vehicle operates at a much lower temperature than previous nanovehicles. Find out more...
Identifying Molecules in Infrared
For the first time, researchers can use infrared spectroscopy to determine what type of bonds protein molecules contain and to identify materials. The new technique has been sought to overcome several limitations of the current, standard technique. Image Credit: Hatice Altug, Electrical Engineering Department, Boston University
An interdisciplinary team of researchers has created a new, ultra-sensitive technique to analyze life-sustaining protein molecules. The technique may profoundly change the methodology of biomolecular studies and chart a new path to effective diagnostics and early treatment of complex diseases. Researchers from Boston University and Tufts University near Boston recently demonstrated an infrared spectroscopy technique that can directly identify the "vibrational fingerprints" of extremely small quantities of proteins, the machinery involved in maintaining living organisms. The new technique exploits nanotechnology to overcome several limitations of current, conventional techniques used to study biomolecules. Previous bio-molecular study methods commonly use fluorescence spectroscopy, where biomolecules are labeled with very bright fluorescence tags to track how efficiently they interact with each other. Understanding interactions is important for medical drug research. Molecules consist of atoms bonded to each other with springs. Depending on the mass of atoms, how stiff these springs are, or how the atoms' springs are arranged, the molecules rotate and vibrate at specific frequencies similar to a guitar string that vibrates at specific frequencies depending on the string length. These resonant frequencies are molecule specific and they mostly occur in the infrared frequency range of the electromagnetic spectrum. The sensitivity of infrared spectroscopy previously had been too low to detect these vibrations, particularly from small quantities of samples. Find out more...
At Stanford, Nanotubes + Ink + Paper = Instant Battery
Stanford University scientists are harnessing nanotechnology to quickly produce ultra-lightweight, bendable batteries and supercapacitors in the form of everyday paper. Simply coating a sheet of paper with ink made of carbon nanotubes and silver nanowires makes a highly conductive storage device, said Yi Cui, assistant professor of materials science and engineering. "Society really needs a low-cost, high-performance energy storage device, such as batteries and simple supercapacitors," he said. Like batteries, capacitors hold an electric charge, but for a shorter period of time. However, capacitors can store and discharge electricity much more rapidly than a battery.
Above: Post doctoral students in the lab of Prof. Yi Cui, Materials Science and Engineering, light up a diode from a battery made from treated paper, similar to what you would find in a copy machine. The paper batteries are treated with a nanotube ink, baked and folded into electrical generating sources like the one wrapped in foil seen here.
(Video Credit: Stanford University)
"These nanomaterials are special," Cui said. "They're a one-dimensional structure with very small diameters." The small diameter helps the nanomaterial ink stick strongly to the fibrous paper, making the battery and supercapacitor very durable. The paper supercapacitor may last through 40,000 charge-discharge cycles – at least an order of magnitude more than lithium batteries. The nanomaterials also make ideal conductors because they move electricity along much more efficiently than ordinary conductors, Cui said. Cui had previously created nanomaterial energy storage devices using plastics. His new research shows that a paper battery is more durable because the ink adheres more strongly to paper (answering the question, "Paper or plastic?"). Find out more...
Nanowires Key to Future Transistors, Electronics
As depicted in this illustration, tiny particles of a gold-aluminum alloy were alternately heated and cooled inside a vacuum chamber, and then silicon and germanium gases were alternately introduced. As the gold-aluminum bead absorbed the gases, it became "supersaturated" with silicon and germanium, causing them to precipitate and form wires. (Image Source: Purdue University, Birck Nanotechnology Center/Seyet LLC)
A new generation of ultrasmall transistors and more powerful computer chips using tiny structures called semiconducting nanowires is closer to reality after a key discovery by researchers at IBM, Purdue University and the University of California at Los Angeles. The researchers have learned how to create nanowires with layers of different materials that are sharply defined at the atomic level, which is a critical requirement for making efficient transistors out of the structures. "Having sharply defined layers of materials enables you to improve and control the flow of electrons and to switch this flow on and off," said Eric Stach, an associate professor of materials engineering at Purdue. Electronic devices are often made of "heterostructures," meaning they contain sharply defined layers of different semiconducting materials, such as silicon and germanium. Until now, however, researchers have been unable to produce nanowires with sharply defined silicon and germanium layers. Instead, this transition from one layer to the next has been too gradual for the devices to perform optimally as transistors. The new findings point to a method for creating nanowire transistors. Whereas conventional transistors are made on flat, horizontal pieces of silicon, the silicon nanowires are "grown" vertically. Because of this vertical structure, they have a smaller footprint, which could make it possible to fit more transistors on an integrated circuit, or chip, Stach said. New technologies will be needed for industry to maintain Moore's law, an unofficial rule stating that the number of transistors on a computer chip doubles about every 18 months, resulting in rapid progress in computers and telecommunications. Doubling the number of devices that can fit on a computer chip translates into a similar increase in performance. However, it is becoming increasingly difficult to continue shrinking electronic devices made of conventional silicon-based semiconductors . Find out more...
New Study Confirms Exotic Electric Properties of Graphene
This illustration shows the tip of a scanning tunneling microscope approaching an undulating sheet of perfect graphene. The exotic substance is 10 times stronger than steel and conducts electricity better than any known material at room temperature. Both physicists and nanoscientists are studying graphene and exploring its potential applications. (Image Source: Vanderbilt Univeristy; Image Credit: Calvin Davidson, British Carbon Group)
First, it was the soccer-ball-shaped molecules dubbed buckyballs. Then it was the cylindrically shaped nanotubes. Now there is graphene: a remarkably flat molecule made of carbon atoms arranged in hexagonal rings much like molecular chicken wire. It is 10 times stronger than steel and conducts electricity better than any other known material at room temperature. These and graphene’s other exotic properties have attracted the interest of physicists, who want to study them, and nanotechnologists, who want to exploit them to make novel electrical and mechanical devices. Although graphene is the first truly two-dimensional crystalline material that has been discovered, over the years scientists have put considerable thought into how two-dimensional gases and solids should behave. They have also succeeded in creating a close approximation to a two-dimensional electron gas by bonding two slightly different semiconductors together. Electrons are confined to the interface between the two and their motions are restrained to two dimensions. When such a system is cooled down to less than one degree above absolute zero and a strong magnetic field is applied, then the fractional quantum Hall effect appears. Since scientists figured out how to make graphene five years ago, they have been trying to get it to exhibit this effect with only marginal success. The best way to understand it is to think of the electrons in graphene as a forming a (very thin) sea of charge. When the magnetic field is applied, it generates whirlpools in the electron fluid. Because electrons carry a negative charge, these vortices have a positive charge. Find out more...
Tiny Light Beam Budges Nanoscale Object
Scanning electron micrograph of two thin, flat rings of silicon nitride, each 190 nanometers thick and mounted a millionth of a meter apart. Under the right conditions optical forces between the two rings are enough to bend the thin spokes and pull the rings toward one another, changing their resonances enough to act as an optical switch. Image Credit: Cornell Nanophotonics Group
With a bit of leverage, researchers have used a very tiny beam of light with as little as 1 milliwatt of power to move a silicon structure up to 12 nanometers. That’s enough to completely switch the optical properties of the structure from opaque to transparent, they report.
The technology could have applications in the design of nanoscale devices with moving parts—known as micro-electromechanical systems (MEMS)—and micro-optomechanical systems (MOMS), which combine moving parts with photonic circuits, says Michal Lipson, associate professor of electrical and computer engineering at Cornell University. Light can be thought of as a stream of particles that can exert a force on whatever they strike. The sun doesn’t knock you off your feet because the force is very small, but at the nanoscale it can be significant. “The challenge is that large optical forces are required to change the geometry of photonic structures,” Lipson explained. Find out more...
Nano-scale Drug Delivery For Chemotherapy
Mouse tumor cells stain red, showing penetration of anti-cancer drug after 24 hours. Image Credit: Pratt School of Engineering, Duke University
Going smaller could bring better results, especially when it comes to cancer-fighting drugs. Duke University bioengineers have developed a simple and inexpensive method for loading cancer drug payloads into nano-scale delivery vehicles and demonstrated in animal models that this new nanoformulation can eliminate tumors after a single treatment. After delivering the drug to the tumor, the delivery vehicle breaks down into harmless byproducts, markedly decreasing the toxicity for the recipient. Nano-delivery systems have become increasingly attractive to researchers because of their ability to efficiently get into tumors. Since blood vessels supplying tumors are more porous, or leaky, than normal vessels, the nanoformulation can more easily enter and accumulate within tumor cells. This means that higher doses of the drug can be delivered, increasing its cancer-killing abilities while decreasing the side effects associated with systematic chemotherapy. Find out more...
Nanotechnology Takes Off!
From Lawrence Berkeley National Labs to Silicon Valley, researchers are manipulating particles at the atomic level, ushering in potential cures for cancer, clothes that do not stain, and solar panels as thick as a sheet of paper. View the video below!
Nanotech Europe as organized by a comprehensive consortium of partners, including Agent-D, the coordination group of the Centers of Competence of Nanotechnology in Germany in cooperation with the Federal Ministry of Education and Research (Germany) and several international partners. Image Credit: Nanotech Europe
Nanotech Europe, which concluded on September 30th, attracted over 600 participants from 50 countries, as well as 64 companies. The event brought together entrepreneurial start-ups and innovative corporations, world-class science, and representatives from government and funding bodies to advance the development of nanotechnology. It provided a forum to address critical success factors for nanotechnology including dialogue between organizations and across industry boundaries, directing public and private sector investment to support innovation, and management of complex industry needs. The event covered a wide range of nanotechnology research and development, including technologies for cancer detection and treatment, high-efficiency solar cells, water purification, high density data storage, novel electronic and photonic devices, and many other life-improving innovations. Nanotech Europe also featured firms in a wide range of industrial sectors discussing their needs from nanotechnology:; Nokia, Shell, Daimler, Thales, Fiat, Bayer and many others discussed their activities and how they see nanotechnology affecting their industry. Find out more...
