Motorola researchers develop selective sensors based on carbon nanotubesSeptember 14, 2006TEMPE, Ariz. - A team of researchers from Arizona State University and Motorola Labs, the applied research arm of Motorola Inc., has developed sensors based on carbon nanotubes, microscopically small structures that posses excellent electronic properties. In early tests, the new devices detected the presence of heavy metal ions in water down to parts per trillion levels. Specifically, the researchers developed a method for applying peptides to single walled carbon nanotubes (SWNT) in field effect transistors. "This is a fairly general sensor platform for all kinds of applications," said Nongjian Tao, an electrical engineering professor at Arizona State University and one of the researchers on the project. "We tested heavy metal ions in water, but the platform can be applied to many other areas to sense toxic chemicals in the air, or they can be used as biosensors when applied to medicine." "Integration of nanosensors into devices and sensor networks will enable the detection of biological and chemical agents at very low concentrations, which could be vital in the areas of public safety and homeland security," added Vida Ilderem, vice president of the Embedded Systems Research Labs at Motorola, Tempe, Ariz. The researchers report the advance in a paper, "Tuning the chemical selectivity of SWNT-FETs for detection of heavy metal ions," which will be published in the journal Small. An early view of the article is available at the journal's web site ( http://www3.interscience.wiley.com/cgi-bin/jissue/109627347 ). "Our sensor is based on the novel properties of peptides and carbon nanotubes," Tao explained. "Peptides can be used to recognize and detect various chemical species with high sensitivity and selectivity while carbon nanotubes are well known for their electronic properties." The peptides are made of 20 or so amino acids, so changing the sequence of amino acids allows the researchers to "tune the peptides and recognize different compounds," Tao said. "We developed a simple way to attach different peptides to different nanotubes." Erica Forzani, an ASU assistant research professor in electrical engineering, said the peptides are selective to specific compounds. In the heavy metal tests, the researchers developed a peptide to detect nickel and one to detect copper. If the nickel peptide were used, it would only detect the presence of nickel and be "blind" to any other heavy metal ion (copper, lead or zinc) passing over the carbon nanotubes. Tao added it's the combination of the structure of the nanotubes and the selectivity of the peptides that make the devices so powerful. "The nanotubes basically are a sheet of interconnected atoms rolled into a tube," Tao said. "Every single atom in the tube is exposed to the environment and can interact with chemicals and molecules. That is why it is so sensitive. But without the peptides, it would not recognize specific compounds." "The potential for the carbon nanotubes is extraordinary," Forzani added, "because with a very simple device that does not require sophisticated electronic circuitry, you can detect very low concentrations of analytes." The researchers now will investigate the use of the sensors on biological molecules, like RNA sequence detection, Tao and Forzani said. Arizona State University |
|||||||||||||||||||||
| Related Carbon Nanotube Current Events and Carbon Nanotube News Articles A recipe for controlling carbon nanotubes Nanoscopic tubes made of a lattice of carbon just a single atom deep hold promise for delivering medicines directly to a tumor, sensors so keen they detect the arrival or departure of a single electron, a replacement for costly platinum in fuel cells or as energy‐saving transistors and wires. Friction force differences could offer a new means for sorting and assembling nanotubes Nanotubes and nanowires are promising building blocks for future integrated nanoelectronic and photonic circuits, nanosensors, interconnects and electro-mechanical nanodevices. But some fundamental issues remain to be resolved - among them, how to position and manipulate the tiny tubes. Carbon nanotubes could make efficient solar cells Using a carbon nanotube instead of traditional silicon, Cornell researchers have created the basic elements of a solar cell that hopefully will lead to much more efficient ways of converting light to electricity than now used in calculators and on rooftops. Nanotubes take flight With products that range from carpets to kites, you'd think Rice University chemist Bob Hauge was running a department store. A Billion Year Ultra-Dense Memory Chip When it comes to data storage, density and durability have always moved in opposite directions - the greater the density the shorter the durability. Inexpensive plastic used in CDs could improve aircraft, computer electronics If one University of Houston professor has his way, the inexpensive plastic now used to manufacture CDs and DVDs will one day soon be put to use in improving the integrity of electronics in aircraft, computers and iPhones. UCLA researchers develop new method for producing transparent conductors Researchers at UCLA have developed a new method for producing a hybrid graphene-carbon nanotube, or G-CNT, for potential use as a transparent conductor in solar cells and consumer electronic devices. UCLA physicists create world's smallest incandescent lamp In an effort to explore the boundary between thermodynamics and quantum mechanics - two fundamental yet seemingly incompatible theories of physics - a team from the UCLA Department of Physics and Astronomy has created the world's smallest incandescent lamp. Sandia researchers construct carbon nanotube device that can detect colors of the rainbow Researchers at Sandia National Laboratories have created the first carbon nanotube device that can detect the entire visible spectrum of light, a feat that could soon allow scientists to probe single molecule transformations, study how those molecules respond to light, observe how the molecules change shapes, and understand other fundamental interactions between molecules and nanotubes. Nanoribbons from sliced open nanotubes: new, faster, more accurate method from Stanford A world of potential may lie tied up in graphene nanoribbons, particularly for electronics applications. But researchers have been hampered in their efforts to fully explore that potential because they had no reliable way of creating the large quantities of uniform nanoribbons needed to conduct extensive studies. More Carbon Nanotube Current Events and Carbon Nanotube News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||