Foresight Nanotech Institute Weekly News Digest: February 21, 2007
Foresight note: The membranes reported here, which can separate molecules according to both size and charge, will find immediate use in near term applications, especially biomedical — but they might also be a big step toward the molecule sorters envisioned for advanced molecular manufacturing.
Headline: Super-thin filter, 50 atoms thick, sorts individual molecules
A newly designed porous membrane, so thin it's invisible edge-on, may revolutionize the way doctors and scientists manipulate objects as small as a molecule.
"It's amazing, we have a material as thin as some of the molecules it's sorting, and even riddled with holes, but can withstand enough pressure to make real-world nano-filtering a practical reality," says research associate Christopher Striemer, co-creator of the membrane. "That ultra-thinness means much higher efficiency and lower sample loss, so we can do things that can't normally be done with current materials."
The membrane is a 15-nanometer-thick slice of the same silicon that's used every day in computer-chip manufacturing. In the lab of Philippe Fauchet, professor of electrical and computer engineering at the University, Striemer discovered the membrane as he was looking for a way to better understand how silicon crystallizes when heated.
In this issue:
Headline: Controlling the movement of water through nanotube membranes
By fusing wet and dry nanotechnologies, researchers at Rensselaer Polytechnic Institute have found a way to control the flow of water through carbon nanotube membranes with an unprecedented level of precision. The research, which will be described in the March 14, 2007 issue of the journal Nano Letters, could inspire technologies designed to transform salt water into pure drinking water almost instantly, or to immediately separate a specific strand of DNA from the biological jumble.
A group of Rensselaer researchers … has found a way to use low-voltage electricity to manipulate the flow of water through nanotubes. Control of water's movement through a nanotube with this level of precision has never been demonstrated before.
Headline: Researchers Create Dual-modality Microbeads
Analyzing human blood for a very low virus concentration or a sample of water for a bioterrorism agent has always been a time-consuming and difficult process. Researchers at the Georgia Institute of Technology and Emory University have developed an easier and faster method to detect these types of target molecules in liquid samples using highly porous, micron-sized, silica beads.
The researchers developed a technique to simultaneously or sequentially add optical and magnetic nanoparticles into the beads. Adding magnetic nanoparticles allows the use of a magnetic field to attract and easily remove the beads from a liquid sample.
Headline: Instruction Manual for Creating a Molecular Nose
An artificial nose could be a real benefit at times: this kind of biosensor could sniff out poisons, explosives or drugs, for instance. Researchers at the Max Planck Institute for Polymer Research and the Max Planck Institute of Biochemistry recently revealed a technique for integrating membrane proteins into artificial structures. Membrane proteins have several important functions in the cell, one of which is to act as receptors, passing on signals from molecules in the air, for example, to the cell interior. They are thus ideal biosensors, but until now were difficult to access in the lab. However, Max Planck scientists have now managed to incorporate in-vitro synthesized membrane proteins directly into artificial lipid membranes (Angewandte Chemie, International Edition, January 15, 2007).
Headline: Nanoscale packaging could aid delivery of cancer-fighting drugs
Nature has produced a well-stocked arsenal of potent cancer-fighting compounds, including Taxol, first isolated from the Pacific yew tree, and rapamycin, borrowed from a soil-dwelling bacterium.
But there's a catch. Many natural anti-cancer molecules are large, complex and fat-soluble, making them tough to administer to patients and keep circulating in the blood long enough to attack their targets.
Working in the emerging field of "nanomedicine," University of Wisconsin-Madison pharmacy professor Glen Kwon aims to improve the delivery of drugs like these by targeting them more selectively to tumors and boosting their solubility in water.
Kwon … coaxes water-insoluble drugs inside nanoscale spheres, called polymeric micelles, which can circulate in the bloodstream for long periods. Like soap, the polymers composing his micelles contain a "hydrophobic" region that repels water and a "hydrophilic" region that attracts it. In water, the polymers spontaneously assemble into tiny spheres, each with a hydrophobic center and a hydrophilic outer shell.
Headline: QUT scientists on the way to sifting out a cure for HIV
HIV may one day be able to be filtered from human blood saving the lives of millions of people, thanks to a world-first innovation by Queensland University of Technology scientists.
QUT scientists have developed specially designed ceramic membranes for nanofiltration, which are so advanced they have the potential to remove viruses from water, air and blood.
Associate Professor Huaiyong Zhu, from QUT's School of Physical and Chemical Sciences, is leading the development of these membranes, also known as nano-mesh, and said preliminary research had proved it successful in removing viruses from water.
Headline: Researchers convert heat to electricity using organic molecules, could lead to new energy source
Researchers at the University of California, Berkeley, have successfully generated electricity from heat by trapping organic molecules between metal nanoparticles, an achievement that could pave the way toward the development of a new source for energy.
The discovery … is a milestone in the quest for efficient ways to directly convert heat into electricity. Currently, the dominant method of power generation involves burning fossil fuels to create heat, often in the form of steam, to spin a turbine that, in turn, drives a generator that produces electricity.
"Generating 1 watt of power requires about 3 watts of heat input and involves dumping into the environment the equivalent of about 2 watts of power in the form of heat," said Arun Majumdar, UC Berkeley professor of mechanical engineering and principal investigator of the study. "If even a fraction of the lost heat can be converted into electricity in a cost-effective manner, the impact it would have on energy can be enormous, amounting to massive savings of fuel and reductions in carbon dioxide emissions."
Headline: Disposable sensor uses DNA to detect hazardous uranium ions
Researchers at the University of Illinois at Urbana-Champaign have developed a simple, disposable sensor for detecting hazardous uranium ions, with sensitivity that rivals the performance of much more sophisticated laboratory instruments.
The sensor provides a fast, on-site test for assessing uranium contamination in the environment, and the effectiveness of remediation strategies, said Yi Lu, a chemistry professor at Illinois and senior author of a paper accepted for publication in the Proceedings of the National Academy of Sciences, and posted on its Web site.
"A unique feature of our uranium sensor is that it contains a small piece of DNA, the same basic building blocks of our genes," said Lu, who also is a researcher at the university's Beckman Institute for Advanced Science and Technology, and at the Center of Advanced Materials for the Purification of Water with Systems. "Our sensor combines the high metal ion selectivity of catalytic DNA with the high sensitivity of fluorescence detection."
While most DNA is double stranded, the catalytic DNA Lu's research group uses has a single strand region that can wrap around like a protein. In that single strand, the researchers fashion a specific binding site — a kind of pocket that can only accommodate the metal ion of choice.
Proceedings of the National Academy of Sciences abstract
Headline: New organic gold-nanoparticle memory device
Researchers have developed a new memory device that uses gold nanoparticles and the organic semiconducting compound pentacene. This novel pairing is a key step forward in the drive to develop organic "plastic" memory devices, which can be considerably cheaper and more versatile than the conventional silicon-based devices used in computers, flash drives, and other applications.
"The ability of gold nanoparticles to self-assemble into ordered arrays gives them great potential in silicon memory applications, as research has shown. We took the next step by combining them with pentacene to form a new organic memory system," said Wei Lin Leong, a materials scientist at Nanyang Technological University, in Singapore, to PhysOrg.com. Leong is the lead author of the paper describing the device, which is published in the January 23 online edition of Applied Physics Letters.
Applied Physics Letters abstract
Do you believe that nanotechnology will give society the ability tackle the hard challenges facing humanity? What's your priority for nanotechnology: cancer treatments and longevity therapies, sustainable energy, clean water, a restored environment, space development, or "zero waste" manufacturing?
If you would like to help influence the direction of this powerful technology, please consider becoming a member of Foresight Nanotech Institute. With your support, Foresight will continue to educate the general public on beneficial nanotechnology and what it will mean to our society.
Headline: Nanotube, heal thyself
News source: Rice University
Pound for pound, carbon nanotubes are stronger and lighter than steel, but unlike other materials, the miniscule cylinders of carbon — which are no wider than a strand of DNA — remain remarkably robust even when chunks of their bodies are blasted away with heat or radiation. A new study by Rice University scientists offers the first explanation: tiny blemishes crawl over the skin of the damaged tubes, sewing up larger holes as they go.
"The shape and direction of this imperfection does not change, and it never gets any larger," said lead researcher Boris Yakobson, professor of mechanical engineering and materials science and of chemistry. "We were amazed by it, but upon further study we found a good explanation. The atomic irregularity acts as a kind of safety valve, allowing the nanotube to release excess energy, in much the way that a valve allows steam to escape from a kettle."
News source: EurekAlert!, a service of AAAS
The safest possible future for advancing nanotechnology in a sustainable world can be reached by using green chemistry, says James E. Hutchison, a professor of chemistry at the University of Oregon.
"Around the world, there is a growing urgency about nanotechnology and its possible health and environmental impacts," Hutchison said in his talk Sunday during a workshop at the annual meeting of the American Association for the Advancement of Science. "There is a concern that these issues will hinder commercialization of this industry."
Scientists need to take a proactive approach to advancing from the current discovery phase in the creation of nanomaterials into a production phase that is efficient and reduces waste, he said. In his talk, Hutchison suggested a green framework for moving the industry forward.
NanoManufacturing Conference & Exhibits
NanoManufacturing is leading the next industrial revolution. Like steam engines, electricity, and transistors, nanotechnology is primed to completely disrupt markets, industries, and business models worldwide. Similarly, it will replace our entire manufacturing base with a new, radically precise, less expensive, and more flexible way of making products. These pervasive changes in manufacturing will leave virtually no product, process, or industry untouched.
This conference will highlight the current, near-term, and future applications of nanotechnology and how they are transforming the way we manufacture products. Peer networking, information sharing, and technology exchange among the world's nanomanufacturing leaders will be a key feature of the event.
Includes Chris Phoenix on exponential molecular nanomanufacturing.
10th Annual NSTI Nanotech Conference and Trade Show
ChinaNANO2007 is intended to stimulate the discussions on the forefront research in nanoscience and technology. The conference will focus on nanoscale materials and structures, self-assembly and growth on surfaces, nano-optics and nanophotonics, nanoelectronics and NEMS, nanobiology and nanomedicine, computation and modeling, nanometrology.
Foresight note: Tiny (micrometer scale) regions of a silicon chip were patterned with DNA molecules, which were then able to interact with other molecules and cellular extracts to produce protein molecules, and the whole system integrated with microfluidics. This advance opens the way for the fabrication of miniature assembly lines on chips, which might accelerate the biotech path to productive nanosystems.
Headline: Biochip allows genes to express themselves
Biochip platforms that work as artificial cells are attractive for medical diagnostics, interrogation of biological processes, and for the production of important biomolecules. However, to match the complexity of nature, the biochips need to be designed such that proteins, DNA, and other important biological components can be located in specific, spatially well-defined regions on the chips.
This allows these devices to mimic the complex, sequential, and often cascaded events involved in biological processes. Now, in a major breakthrough, a group of researchers at the Weizmann Institute of Science in Israel, led by Roy Bar-Ziv, in collaboration with Margherita Morpurgo from the University of Padova in Italy, have designed a molecule affectionately called the "daisy" that is able to bind genes onto chips in miniature patterned arrays.
These biochips can act as protein microtraps, selectively trapping specific proteins from crude cell extracts with high spatial resolution. Moreover, the gene sequences immobilized on the biochips can be used for the on-chip production of proteins by transcription/translation processes such as those occurring within cells.
We continue our tradition of citing a special story that strikes the Editor as especially cool, but which doesn't fit within the usual editorial categories of the News Digest.
The most useful applications of this research are not yet obvious, but it has elegantly established the frontier of one class of nanodevices. In the author's words in their Science abstract, "The thinnest resonator consists of a single suspended layer of atoms and represents the ultimate limit of two-dimensional nanoelectromechanical systems."
News source: Cornell University, written by Lauren Gold
Scott Bunch found that a single sheet of graphene, a form of carbon atoms in a plane just one atom thick, can be isolated and used as an electromechanical resonator. The material could be useful for weighing atoms and molecules, which have extremely small masses; as a membrane to separate gases or to measure pressure; or for other experiments that call for a very stiff but exceptionally thin and light sheet of material.
News source: Nanodot
One advanced tool for nanotechnology that has been proposed is the disassembler, a molecular machine system that could take apart objects atom-by-atom and record their structure to that level of precision. Sarah Fister Gale at Small Times brings us news of a macroscale tool that claims to be able to do something quite similar:
"The LEAP [Local Electrode Atom Probe], one of only four such tools in North America, uses a high electric field to remove individual atoms from material surfaces and a position-sensitive detector to record information that reveals the atom's position and identity. The incorporation of a local electrode eliminates or mitigates many of the performance limitations of traditional atomic probe tomographs (ATPs). It can rapidly analyze the molecular make-up of metals and plastics down to their atomic structure, and projects [a] statistically relevant 3D image of the nanostructure …
"Experiments that used to take 10 months to complete, can now be conducted in less than 16 hours …"
It's being used by Ford to design new materials now, but it should be useful as we move toward nanodevices and nanosystems requiring atomic precision.
— Nanodot post by Christine Peterson
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