Nanodot: the original nanotechnology weblog

A discovery of unexpected properties of an insulating layer only a few atoms thick may lead to a new nanotech approach to faster computers by sorting electrons according to their spins. From University of California - Riverside, via AAAS EurekAlert “Discovery by UC Riverside physicists could enable development of faster computers“:

Physicists at UC Riverside have made an accidental discovery in the lab that has potential to change how information in computers can be transported or stored. Dependent on the “spin” of electrons, a property electrons possess that makes them behave like tiny magnets, the discovery could help in the development of spin-based semiconductor technology such as ultrahigh-speed computers.

The researchers were experimenting with ferromagnet/semiconductor (FM/SC) structures, which are key building blocks for semiconductor spintronic devices (microelectronic devices that perform logic operations using the spin of electrons). The FM/SC structure is sandwich-like in appearance, with the ferromagnet and semiconductor serving as microscopically thin slices between which lies a thinner still insulator made of a few atomic layers of magnesium oxide (MgO).

The researchers found that by simply altering the thickness of the MgO interface they were able to control which kinds of electrons, identified by spin, traveled from the semiconductor, through the interface, to the ferromagnet. Read the rest of this entry »

A nanotech formulation may have saved one of the most promising broad-spectrum antiangiogenesis cancer therapies from being side-tracked due to neurotoxic side effects. From Children’s Hospital Boston via Science Daily “New Oral Angiogenesis Inhibitor Offers Potential Nontoxic Therapy For A Wide Range Of Cancers“:

The first oral, broad-spectrum angiogenesis inhibitor, specially formulated through nanotechnology, shows promising anticancer results in mice, report researchers from Children’s Hospital Boston.

Findings were published online on June 29 by the journal Nature Biotechnology [abstract].

Because it is nontoxic and can be taken orally, the drug, called Lodamin, may be useful as a preventive therapy for patients at high risk for cancer or as a chronic maintenance therapy for a variety of cancers, preventing tumors from forming or recurring by blocking the growth of blood vessels to feed them.

Lodamin may also be useful in other diseases that involve aberrant blood-vessel growth, such as age-related macular degeneration and arthritis.

…While a number of angiogenesis inhibitors, such as Avastin, are now commercially available, most target only single angiogenic factors, such as VEGF, and they are approved only for a small number of specific cancers. In contrast, Lodamin prevented capillary growth in response to every angiogenic stimulus tested. Moreover, in mouse models, Lodamin reduced liver metastases, a fatal complication of many cancers for which there is no good treatment.

—Jim

Producing highly porous nanostructures made from metal is difficult because metal atoms are unhappy in structures having very high surface areas. By coating metal nanoparticles with organic molecules and using a block co-polymer as a scaffold, a novel nanotech procedure produces metal nanostructures containing uniform hexagonal pores about 10 nm across that could supply new catalysts, faster metal wires for microchips, and better optical materials. From the National Science Foundation, via AAAS EurekAlert “Metals shape up with a little help from friends“:

New method ’self-assembles’ metal atoms into porous nanostructures

For 5,000 years the only way to shape metal has been by the “heat and beat” technique. Even with modern nanotechnology, metalworking involves carving metals with electron beams or etching them with acid.

Now Cornell researchers have developed a method to self-assemble metals into complex configurations with structural details about 100 times smaller than a bacterial cell by guiding metal particles into the desired form using soft polymers.

“I think this is ingenious work that takes the fundamental concepts of polymer science and applies them to make metals in a totally novel way,” said Andrew Lovinger, the director of the Polymers Program at the National Science Foundation. “In so doing, it opens the door to all kinds of new possibilities.” Read the rest of this entry »

In yet another nanotech approach to cancer therapy, researchers demonstrated in laboratory experiments that antibody-coated carbon nanotubes only bind to cancer cells targeted by the antibody, and that irradiation with near-infrared light causes the bound carbon nanotubes to heat up and kill the cancer cells. From UT Southwestern Medical Center, via AAAS EurekAlert (credit KurzweilAI.net) “Nanotechnology, biomolecules and light unite to ‘cook’ cancer cells“:

Researchers are testing a new way to kill cancer cells selectively by attaching cancer-seeking antibodies to tiny carbon tubes that heat up when exposed to near-infrared light.

Biomedical scientists at UT Southwestern Medical Center and nanotechnology experts from UT Dallas describe their experiments in [the] Proceedings of the National Academy of Sciences [abstract].

Scientists are able to use biological molecules called monoclonal antibodies that bind to cancer cells. Monoclonal antibodies can work alone or can be attached to powerful anti-cancer drugs, radionuclides or toxins to deliver a deadly payload to cancer cells.

In this study, the researchers used monoclonal antibodies that targeted specific sites on lymphoma cells to coat tiny structures called carbon nanotubes. Carbon nanotubes are very small cylinders of graphite carbon that heat up when exposed to near-infrared light. This type of light, invisible to the human eye, is used in TV remote controls to switch channels and is detected by night-vision goggles. Near-infrared light can penetrate human tissue up to about 1½ inches. Read the rest of this entry »

A major nanotech advance in engineering multifunctional nanoparticles for imaging and therapeutic applications combines a short RNA (siRNA) to “silence” a specific gene with quantum dots and a “proton sponge” polymer coating to get the siRNA into the cell and released into the right compartment of the cell, rendering it both much more efficient and much less toxic to the cell. From the University of Washington, via AAAS EurekAlert “Gene silencer and quantum dots reduce protein production to a whisper“:

More than 15 years ago scientists discovered a way to stop a particular gene in its tracks. The Nobel Prize-winning finding holds tantalizing promise for medical science, but so far it has been difficult to apply the technique, known as RNA interference, in living cells.

Now scientists at the University of Washington in Seattle and Emory University in Atlanta have succeeded in using nanotechnology known as quantum dots to address this problem. Their technique is 10 to 20 times more effective than existing methods for injecting the gene-silencing tools, known as siRNA, into cells.

“We believe this is going to make a very important impact to the field of siRNA delivery,” said Xiaohu Gao, a UW assistant professor of bioengineering and co-author of a study published online this week in the Journal of the American Chemical Society [abstract]. Read the rest of this entry »

A very brief but intriguing article on ScienceDaily reports that millimeter-scale nanotech structures self-assembled from hybrid nanowires can sense and respond to external stimuli, like magnetic fields and light. From “Building Giant ‘Nanoassemblies’ That Sense Their Environment“:

Researchers in Texas are reporting the design, construction, and assembly of nano-size building blocks into the first giant structures that can sense and respond to changes in environmental conditions.

The study, scheduled for the July 9 issue of ACS’s Nano Letters [abstract]… terms those structures “giant” because they are about the size of a grain of rice — millions of times larger than anything in the submicroscopic realm of the nanoworld.

In the new study, Pulickel M. Ajayan and colleagues point out that such structures are a step toward the development of futuristic nanomachines with practical applications in delivering medicines to patients, labs-on-a-chip, and other products. Until now, scientists have had difficulty in using nanomaterials to build more complex, multifunctional objects needed for those applications.

—Jim

To live long enough to experience some of the more dramatic applications of nanotechnology, you may need anti-aging treatments. For all of us with an interest in longevity, the place to be starting at 4 PM this Friday, June 27, is UCLA for Aging 2008:

At Aging 2008 you will engage with top scientists and advocates as they present their findings and advice, and learn what you can do to help accelerate progress towards a cure for the disease and suffering of aging.

To get into the real nitty-gritty technical details, stick around for the scientific conference on Saturday and Sunday. –Christine

Exposure to two different wavelengths of light can cause the azobenzene molecule to switch back and forth between two different shapes. This molecular shape-changing works well in solution but until now has not worked with molecules attached to surfaces. Now scientists from Penn State University and Rice University have found a way to make the switching work when the molecules are tethered to a surface—a first step toward making this molecular switching useful for nanotech devices. From Penn State (via PhysOrg.com) “Tethered molecules act as light-driven reversible nanoswitches“:

The ability to see is based on molecules in the eye that flip from one conformation to another when exposed to visible light. Now, a new technique for attaching light-sensitive organic molecules to metal surfaces allows the molecules to be switched between two different configurations in response to exposure to different wavelengths of light. Because the configuration changes are reversible and can be controlled without direct contact, this technique could enable applications that can be controlled at the molecular scale.

The technology has been suggested as a possible basis for molecular motors, artificial muscles, and molecular electronics. The research results, obtained by a team led by Paul S. Weiss, distinguished professor of chemistry and physics at Penn and James M. Tour, Chao professor of chemistry at Rice University, are reported in the June issue of the journal Nano Letters [abstract]. Read the rest of this entry »

A nanotech version of the optical tweezers traditionally used to manipulate micrometer-scale objects manipulates objects at the 200-nm scale. From nanotechweb.org, written by Belle Dumé (requires free registration) “Nanotweezers trap tiny objects“

Researchers have made the first nano-optical tweezers. The devices, which are based on “nanopillars”, offer many advantages over traditional optical tweezers and can trap and move objects on the nanoscale. The breakthrough result opens the way to manipulating fragile biological cells and making structures from nanoscale building blocks.

Traditional optical tweezers, which have been around for decades, are one of the most important modern-day tools in biology, physics and chemistry. They work by trapping micron-scale objects near the focus of a laser beam. The technique allows objects to be picked up and moved to another place using just light.

Although scientists have used optical tweezers to trap nanoscale objects before, this required high laser powers, which can damage or even destroy the object in question. Now, Alexander Grigorenko and colleagues at the University of Manchester in the UK have made nanoscale optical tweezers that overcome this problem. The new devices have a much bigger trapping force and provide significantly smaller trapping volumes for much less laser power than employed in ordinary optical tweezers. Read the rest of this entry »

Following a roadmap for organic and printed electronics a new concept for a very cheap plastic nanotech memory has been developed by combining the favorable properties of ferroelectrics and semiconductors. From the University of Groningen, via Nanowerk News “Researchers develop ultra low-cost plastic memory“

Researchers at the Zernike Institute of Advanced Materials at the University of Groningen have developed a technology for a plastic ferro-electric diode which they believe will achieve a breakthrough in the development of ultra low-cost plastic memory material. Their findings will be published in the July edition of Nature Materials [abstract], a publication of the leading scientific journal Nature.

The newly developed technology is similar to that used in Flash memory chips. In both cases, the memory retains data without being connected to a power source. Flash memory chips are used in memory sticks, MP3 players, cellular phones and in the memory cards of digital cameras. The researchers at the Zernike Institute of Advanced Materials expect the new technology to lead to the development of comparable products possibly even more significant Read the rest of this entry »

While searching for genes involved in how bacteria stop moving around and settle into stationary communities called biofilms, scientists discovered a molecular clutch that disengages the powerful molecular motor that spins the flagellum that propels the bacteria. This flagellum clutch mechanism may provide ideas useful for nanotech control of molecular motors. From Indiana University, via AAAS EurekAlert “Microscopic ‘clutch’ puts flagellum in neutral“:

A tiny but powerful engine that propels the bacterium Bacillus subtilis through liquids is disengaged from the corkscrew-like flagellum by a protein clutch, Indiana University Bloomington and Harvard University scientists have learned. Their report appears in this week’s Science [abstract].

Scientists have long known what drives the flagellum to spin, but what causes the flagellum to stop spinning — temporarily or permanently — was unknown.

“We think it’s pretty cool that evolving bacteria and human engineers arrived at a similar solution to the same problem,” said IU Bloomington biologist Daniel Kearns, who led the project. “How do you temporarily stop a motor once it gets going?”

The action of the protein they discovered, EpsE, is very similar to that of a car clutch. Read the rest of this entry »

One of the most promising applications of near-term nanotech is the production of nanostructured materials for use in energy applications, like less expensive solar cells. Nanostructured materials can prove superior in surprising ways. Here carbon nanotubes with the proper imperfections were found to replace more problematic and expensive materials in dye-sensitized solar cells. From Santa Fe Institute, via AAAS EurekAlert “Perfecting a solar cell by adding imperfections“:

Nanotechnology is paving the way toward improved solar cells. New research shows that a film of carbon nanotubes may be able to replace two of the layers normally used in a solar cell, with improved performance at a lower cost. Researchers have found a surprising way to give the nanotubes the properties they need: add defects.

Currently, these solar cells, called dye-sensitized solar cells, have a transparent film made of an oxide that is applied to glass and conducts electricity. In addition, a separate film made of platinum acts as a catalyst to speed the chemical reactions involved.

Both of these materials have disadvantages, though. The oxide films can’t easily be applied to flexible materials: they perform much better on a rigid and heat resistant substrate like glass. This increases costs and limits the kinds of products that can be made. And expensive equipment is necessary to create the platinum films. Read the rest of this entry »

The combination of electrical stimulation and a nanotech surface composed of carbon nanotubes dispersed in polycarbonate urethane was found to attract cartilage-forming cells, which might lead to a treatment to regenerate lost or damaged cartilage. Excerpts from “Brown researchers work toward ending cartilage loss” (via KurzweilAI.net):

…Brown University nanotechnology specialist Thomas Webster has found a way to regenerate cartilage naturally by creating a synthetic surface that attracts cartilage-forming cells. These cells are then coaxed to multiply through electrical pulses. It’s the first study that has shown enhanced cartilage regeneration using this method; it appears in the current issue of the Journal of Biomedical Materials Research, Part A (abstract).

…Webster and his team, including Brown researcher Dongwoo Khang and Grace Park from Purdue University, found that the tubes, due to their unique surface properties, work well for stimulating cartilage-forming cells, known scientifically as chondrocytes. The nanotube’s surface is rough; viewed under a microscope, it looks like a bumpy landscape. Yet that uneven surface closely resembles the contours of natural tissue, so cartilage cells see it as a natural environment to colonize. Read the rest of this entry »

Chemists have designed molecules that act like nanotech sensing robots by signaling information about their chemical environment. From NewScientist.com news service, written by Jon Evans, “Molecular ‘robots’ explore cellular landscapes” (via KurzweilAI.net):

Molecular “robots” have been developed by chemists to explore the unmapped chemical environments of living cells and transmit back the results.

The new molecules encrypt measurements of two different chemical features of cell membranes into light signals to be decoded by the British and Japanese chemists that built them. One measurement is encoded in the light’s intensity, and the other in its wavelength, or colour.

Being able to map the variables they measure could help biochemists probe the mechanisms by which cells generate energy, or how signals travel through nerve cells.

“Concepts of nanorobotic vehicles and of mapping out nanospaces have emerged from science fiction into experimental science for the first time,” lead researcher A. Prasanna de Silva at Queen’s University, Belfast, UK, told New Scientist.

…”This is the first time that the proton distribution near a membrane has been mapped in such detail,” says de Silva. “This is also the first time that a family of sensor molecules have delivered two separate kinds of information simultaneously from a series of locations.”

The research was published in Angewandte Chemie (citation)
—Jim

Two different types of nanostructures have been reported as nanotech methods to clean up oil spills and other organic pollutants. Researchers at MIT have developed a nanowire mesh that can reversibly absorb 20 times it weigh in oil. Researchers at Rice have shown how specially designed “nanobatons” can trap oil droplets by spontaneously assembling into sacs. From MIT News, written by Elizabeth A. Thomson “MIT develops a ‘paper towel’ for oil spills” (via PhysOrg.com):

Nanowire mesh can absorb up to 20 times its weight in oil

A mat of nanowires with the touch and feel of paper could be an important new tool in the cleanup of oil and other organic pollutants, MIT researchers and colleagues report in the May 30 online issue of Nature Nanotechnology [abstract].

The scientists say they have created a membrane that can absorb up to 20 times its weight in oil, and can be recycled many times for future use. The oil itself can also be recovered. Some 200,000 tons of oil have already been spilled at sea since the start of the decade.

“What we found is that we can make ‘paper’ from an interwoven mesh of nanowires that is able to selectively absorb hydrophobic liquids—oil-like liquids—from water,” said Francesco Stellacci, an associate professor in the Department of Materials Science and Engineering and leader of the work. Read the rest of this entry »

Detailed calculations show that electrons passing through a ‘turbine’ in which one type of carbon nanotube (CNT) is suspended inside another type of CNT would cause the inner CNT to rotate, forming an electron ‘windmill’ or turbine. The researchers also suggest that atoms or molecules could be pumped through the spinning inner CNT to form patterns of atoms or molecules—a nanotech inkjet printer. From NewScientist.com news service, written by Kate McAlpine: “‘Electron turbine’ could print designer molecules“, via KurzweilAI.net

A carbon nanotube that spins in a current of electrons, like a wind turbine in a breeze, could become the world’s smallest printer or shrink computer memory, UK researchers say.

The design is simple. A carbon nanotube 10 nanometres long and 1 nm wide is suspended between two others, its ends nested inside them to form a rotating joint. When a direct current is passed along the tubes, the central one spins around.

That design has as yet only been tested using advanced computer simulations by Colin Lambert and colleagues at Lancaster University, Lancashire, UK.

But Adrian Bachtold of the Catalan Institute for Nanotechnology, who was not involved in the work, intends to build the electron turbines and says it should be straightforward. Read the rest of this entry »

For nanotech drug delivery methods to work properly, the nanoparticles must enter the cells without damaging the cell membrane, and then end up in the right compartment of the cell. MIT scientists are discovering what controls the proper movement of nanoparticles into cells—the right kinds of molecules must be arranged in the right patterns. From MIT News: “Stripes key to nanoparticle drug delivery”, written by Elizabeth A. Thomson, via KurzweilAI.net

In work that could at the same time impact the delivery of drugs and explain a biological mystery, MIT engineers have created the first synthetic nanoparticles that can penetrate a cell without poking a hole in its protective membrane and killing it.

The key to their approach? Stripes.

The team found that gold nanoparticles coated with alternating bands of two different kinds of molecules can quickly pass into cells without harming them, while those randomly coated with the same materials cannot. Read the rest of this entry »

An item from the June newsletter of the Innovation Society (based in St.Gallen, Switzerland) announces a training course for secondary school science teachers to help them develop a teaching syllabus on nanotech:

Innovation Society introduces teachers’ training course “TEACH-NANO”

As nanotechnology is coming into our daily lives it will also conquer schools in the near future. Nanotechnology will be an important part of curricula of science classes in secondary schools, and already today teachers are approached by their students who want to know more about this new technology and its amazing applications. The increased media coverage of nanotechnology and the presence of nanoproducts in stores will add to this trend. For the creation of an interesting instruction syllabus that is oriented on the practical use of nanotechnology, teachers until now have only had limited resources at their disposal. Until now there are no nanospecific schoolbooks available. Due to the rapid development of the field many teachers have not come into contact with nanotechnologies during their initial training and therefore have a growing knowledge deficit in this area. Read the rest of this entry »

To better understand the potential of graphene for nanotech applications, scientists in California, New York, and Florida measured the dynamics of how charges move in response to electromagnetic radiation in a 50-micrometer square of graphene integrated into a solid state electronic device. Their very precise measurements confirmed many of the unusual effects theoretically predicted for graphene, but they also discovered effects of unanticipated additional interactions, which are not yet understood. From a Lawrence Berkeley National Laboratory new release “Surprising Graphene: Honing in on graphene electronics with infrared synchrotron radiation” (via ScienceDaily):

Graphene is the two-dimensional crystalline form of carbon: a single layer of carbon atoms arranged in hexagons, like a sheet of chicken wire with an atom at each nexus. As free-standing objects, such two-dimensional crystals were believed impossible to create — even to exist — until physicists at the University of Manchester actually made graphene in 2004.

Now researchers at the Department of Energy’s Advanced Light Source (ALS), from DOE’s Lawrence Berkeley National Laboratory and the University of California at San Diego (UCSD), have measured the extraordinary properties of graphene with an accuracy never before achieved.

The results confirm many of the strangest features of the unusual material but also reveal significant departures from theoretical predictions. And they point the way to novel practical applications, such as tunable optical modulators for communications and other nanoscale electronics.

The research was published in Nature Physics (abstract).
—Jim

Using computational methods to guide their experimental work, Australian and Chinese researchers have developed a method of producing titanium oxide crystals with more reactive surfaces, providing a path to commercially available nanotech methods within five years for removing pollution from water and air, within ten years for solar energy conversion. From the University of Queensland “UQ researchers make breakthrough in renewable energy materials“, via PhysOrg.com:

University of Queensland researchers have made a ground-breaking discovery that produces highly efficient miniature crystals which could revolutionise the way we harvest and use solar energy.

Professor Max Lu, from UQ’s Australian Institute for Bioengineering and Nanotechnology (AIBN), said they were one step closer to the holy grail of cost-effective solar energy with their discovery.

“We have grown the world’s first titanium oxide single crystals with large amounts of reactive surfaces, something that was predicted as almost impossible,” Professor Lu said.

“Highly active surfaces in such crystals allow high reactivity and efficiency in devices used for solar energy conversion and hydrogen production.

“Titania nano-crystals are promising materials for cost-effective solar cells, hydrogen production from splitting water, and solar decontamination of pollutants.

“The beauty of our technique is that it is very simple and cheap to make such materials at mild conditions.

“Now that the research has elucidated the conditions required, the method is like cooking in an oven and the crystals can be applied like paints.”

The research was published in Nature (abstract)
—Jim