The structure of Aleksandr Noy’s new transistor is unimpressively simple: just a carbon nanotube connecting two metal electrodes. But what makes it special is what he and his team use to control it: adenosine triphosphate (ATP), the fuel from our own cells. The project, published in a study in Nano Letters, achieves a key step in unifying man and machine.

The way it works: An insulator coats the ends of the nanotube, but not the middle—it’s left exposed.

The entire device is then coated again, this time with a lipid bi-layer similar to those that form the membranes surrounding our body’s cells [New Scientist].

Finally, the team poured a solution of ATP plus potassium and sodium across the transistor. That created an electric current, one that was stronger the more ATP they poured.

The magic is in the lipid bi-layer, which contains an ATP-sensitive protein that serves as a kind of ion pump when ATP is present. The lipid hydrolyses ATP molecules, with each occurence causing three sodium ions to move one way through the lipid and two potassium ions to move the other way, netting one charge across the bi-layer to the nanotube [Popular Science].

Noy claims to have created “the first example of a truly integrated bioelectronic system,” New Scientist says. And as simple as the transistor is, the idea behind it—harnessing the energy already in our bodies to power electronics—will be one of the keys to creating battery-free devices that monitor our cells, connect to our brains, or do things we won’t think of until we’ve (finally!) got nanodevices hooked up to our brains.

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Image: Aleksandr Noy et. al.

Scientists have created the world’s smallest superconductor, made out of just four molecule-pairs and less than a nanometer wide. That’s far smaller than the head of a pin — which stretches across a million nanometers — and more on the order of a DNA molecule, which is about 2 nanometers wide [PopSci]. The invention, described in the journal Nature Nanotechnology, provides the first evidence that nanoscale molecular superconducting wires can be fabricated, which could be used for nanoscale electronic devices and energy applications [Xinhua]. Superconductive materials allow electrical currents to pass through with zero resistance, making them potentially useful to a wide variety of industries.

Lead author Saw-Wai Hla, a physics professor at Ohio University’s Nanoscale and Quantum Phenomena Institute, explains that earlier it was almost impossible to make nanoscale interconnects using metallic conductors because the resistance increased as the size of wire becomes smaller. “The nanowires become so hot that they can melt and destruct. That issue, Joule heating, has been a major barrier for making nanoscale devices a reality” [Xinhua], Hla says.

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So far in 2010 we’ve seen nanotubes that carry thermopower waves to create electricity, nanoparticles that latch onto only damaged cells to deliver drugs there, and more. Today there are a couple more clever uses for nanotechnology—taking the salt out of salt water, and nanobots that deliver gene therapy.

In Nature Nanotechnology, an MIT team showed they could use nanotech to desalinate water in a new way. At the moment, desalination plants employ reverse osmosis, in which pressure forces the salt ions through a membrane. But this process is an energy-gobbler and the membrane is prone to clogging, which means that de-sal plants are inevitably big, expensive, fixed pieces of kit [Sydney Morning Herald].

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Carbon nanotubes have shown the potential to help us take better x-ray images, make cheaper hydrogen fuel cells, and replace silicon in computer chips. Add another possibility onto the pile: MIT researchers report this week in Nature Materials that they’ve used carbon nanotubes to create thermopower waves, a system they say could put out 100 times more energy than a lithium-ion battery.

Michael Strano’s team coated the tubes, which are only billionths of a meter across, with a fuel. This fuel was then ignited at one end of the nanotube using either a laser beam or a high-voltage spark, and the result was a fast-moving thermal wave traveling along the length of the carbon nanotube like a flame speeding along the length of a lit fuse [Environmental News Service]. That wave travels 10,000 times the typical speed of this chemical reaction, and the heat blasts electrons down the tubes. Voila, electric current.

This previously unknown phenomenon opens up an entirely new area of energy research, Strano says, and the technology’s potential applications are exciting. Strano envisions thermopower waves that could enable ultra-small electronic devices, no larger than a grain of rice, perhaps a sensor or treatment device that could be injected into the body. Or they might be used in “environmental sensors that could be scattered like dust in the air,” he says [Environmental News Service].

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We’ve brought you stories of lab-created blood cells able to simulate red blood cells in humans, or to act like platelets in rodents and stop bleeding. Now, in a study soon to be published in the Proceedings of the National Academy of Sciences, comes a new, even smaller creation for our bloodstreams: A nanoparticle that could target and latch onto only the damaged cells in arteries around the heart to deliver drugs there.

The MIT researchers, led by Robert Langer, have developed other nanoparticles to target cancer; this new particle they call a “nanoburr,” named for those seeds covered in bristles or hooks that latch onto animals passing by. Its nanoburrs are coated with proteins which can only stick to a structure in the blood vessel wall called the “basement membrane.” This is only exposed when the wall is damaged, so only damaged sections of blood vessel are targeted [BBC News]. Then the particle can slowly release the drug stored inside.

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In the not too distant future, testing for certain cancers may be completed in less time than it takes to watch an episode of Scrubs.  A new portable device, expected to be about the size of a paperback book, works by detecting biomarkers in the blood, substances that suggest that a patient is diseased. The sensor, which uses nanotechnology, is so accurate that it could pick up a grain of salt in a swimming pool, claim the researchers [Telegraph]. With just a small amount of blood and 20 minutes, doctors can have an electronic read out of biomarker concentrations at their fingertips. The research, led by Mark Reed at Yale University,  may lead to quick, easy, and low-cost cancer tests.

Reed says the technology would be ideal for measuring lung cancer biomarkers in a phlegm sample, or colon or ovarian cancer biomarkers in a blood sample, making their technology the first to measure biomarkers from normal samples of bodily fluids. Previous technologies work in much the same way, but can only detect biomarkers in purified solutions, not the real thing — meaning fluid samples from patients [U.S. News and World Report]. The applications aren’t limited to cancer biomarker measurements; the researchers say they could also measure cardiovascular disease biomarkers in small blood samples. The scientists have published their research in the journal Nature Nanotechnology.

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Image: Mark Reed / Yale University

Toys, refrigerators, washing machines, socks—more and more products contain silver nanoparticles. It’s no wonder: These particles, which measure less 100 nanometers (smaller than a single HIV virus), can kill microbes on contact. But, researcher Darin Furgeson says, nanosilver can also escape into ecosystems and cause serious damage to fish embryos. Furgeson’s team published its results in the journal Small.

In one new experiment, Furgeson, a professor of pharmaceutical sciences, exposed zebrafish embryos to silver nanoparticles in a laboratory, and found that some died and others were left with dramatic mutations. “Some of the fish became extremely distorted, almost making a number nine or a comma instead of a linear fish,” he said [Scientific American]. Eyes, tails, and other body parts turned out malformed in the fish that survived.

Just how much nanosilver gets into the environment? A separate study from Environmental Science & Technology washed nine kinds of nanosilver-containing textiles, including some “anti-bacterial and anti-odor socks” that are already on the market. The researchers found that anywhere from less than 1 percent to as high as 45 percent of the silver came out in the first wash. Most of the silver was in the form of coarse particles of greater than 450 nanometers, suggesting that mechanical stress in the washing machine was responsible for most of the release [The New York Times], and that the nanoparticles might have aggregated to reach that size.

Those nanoparticles flushed out by a washing machine can end up in both fish habitats and drinking water supplies. Furgeson says his fish experiments could help show whether nanosilver is a health concern for humans, too. “Zebrafish have similar tissues and organs to us,” Furgeson said. “They don’t have lungs, but they do have a liver, kidneys and heart – though it is only two chambered – and they have a blood-brain barrier” [Scientific American].

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Image: Wiki Commons / Kristof vt

Contact lenses provide a number of convenience advantages over glasses, but one they come up short in one area—you can’t get contacts that automatically adjust to the sun’s UV light and darken, like the photochromic lenses many bespectacled people enjoy. But that could soon change: Researchers in Singapore led by Jackie Ying have now created a contact lens that responds to UV light.

Transition lenses for glasses are coated with a dye that is transparent when out of the sun, but responds to UV light by changing shape and darkening. Few previous attempts have been made to design transition contact lenses, largely because it’s difficult to apply dye coatings uniformly to the delicate, soft surface of a contact lens. Ying and her colleagues got around this by developing a contact lens that embeds dyes uniformly throughout the material [Technology Review].

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“Nanoparticles can cause DNA damage across a cellular barrier.” That’s the title of a paper published in Nature Nanotechnology that inspired a number of ominous news headlines (two examples: Nanoparticles ‘can damage DNA‘ and Nanoparticles can damage DNA at a distance: study). The stories that followed basically sang the same tune—that nanoparticles can damage our cells’ genetic material even from a distance (a relatively short distance of four cells away). However, experts are speaking up in response to the media hype, and argue that this study should have never been covered in the news. This particular study has little relevance to human exposure risks, experts say, and it is deeply flawed in other ways [ScienceNOW Daily News]. At least one expert called the study “meaningless,” however other scientists were more diplomatic and have pointed to a number of interesting questions the study raises that are worth pursuing.

In the study, researchers exposed a thin “barrier” of four layers of cancer cells to cobalt-chromium ions or particles. Cells close to the nanoparticles experienced signs of mitochondrial damage. But even cells on the other side of the barrier suffered some DNA damage, the team found, despite the fact that there was no evidence that the metals themselves moved through the cells to the other side of the barrier [ScienceNOW Daily News]. Interesting indeed, but experts are pointing out that this set-up is not entirely relevant to humans, or any living organism for that matter.

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Cancer treatment in the future could have dramatically reduced side effects if new nanotechnology research proves useful. Heat-sensitive nanoparticles might be able to deliver drugs to a targeted location in the body—to a tumor, say—and release them on cue, a sought-after goal of biomedical research.

One research team has developed nanoparticle cages that can be stuffed with tiny amounts of drugs that are only released on demand. These “nanocages” are cubes of gold, with sides about 50-billionths of a meter long and holes at each corner. They are easily made, using silver particles as a mold, and then coated with strands of a smart polymer. The polymer strands are normally extended and bushy and cover the holes in the cube. But when heated the strands collapse, leaving the holes open and allowing the drug inside to escape [The New York Times]. The researchers say they can engineer the nanocages to stick to tumors.

Doctors could release the packaged drugs whenever they want, just by zapping the cages inside the patient’s body with near-infrared light. Near-infrared wavelengths are not greatly absorbed by body tissues, so light from a near-infrared laser could penetrate a couple of inches inside the body, but they are absorbed by gold [The New York Times]. Researchers could design the cages to fall apart at just a few degrees above normal body temperature, so they only spill their contents where the heat is applied; they could also alter the drug’s rate of release by adjusting the laser’s intensity. The technology, described in the journal Nature Materials, could help cut down on the side effects of today’s treatments which are often caused by toxic drugs coursing through the body.

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Image: Younan Xia, Washington University in St. Louis

A new study may have hit upon another way to improve stem cells‘ ability to help repair damaged tissue. While stem cells can rapidly grow into any kind of new tissue, they aren’t always able to encourage new blood vessels to grow so that the tissue stays alive. But in a new study, published in the Proceedings of the National Academy of Sciences, scientists describe a way around the problem. The researchers used nanoparticles to ferry a key gene into the stem cells, which caused the cells to recruit new blood vessels, thus fueling tissue growth.

The nanoparticles carried a gene (VEGF) that is known to stimulate new blood vessel growth. When the modified cells were injected into mice whose hind limbs had been injured, the tissue that regrew to repair the damage had three times the blood vessel density of similar tissue in mice given unmodified cells. Four weeks later, only 20 per cent of the mice given modified cells had lost limbs, compared with 60 per cent in mice that received unmodified cells [New Scientist].

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Scientists have used nanotechnology in some bizarre applications—nanotube speakers and glue are just two examples. Now carbon nanotubes may have a use as fertilizer, according to a new study. Plant biologist Mariya Khodakovskaya and nanotechnologist Alexandru Biris … planted tomato seeds in a growth medium that contained carbon nanotubes. They found that the seeds germinated sooner and seedlings grew faster than those in a non-treated medium [New Scientist]. After 12 days, 72 percent of the treated seeds had germinated compared with 30 percent of the untreated group. After four weeks, the nanotube-supplemented seeds were twice as tall and had twice the biomass. However, the root systems in both groups were roughly the same.

Similar findings have been reported previously, but until now nobody understood how nanotubes sped and enhanced plant growth. The new study, which recently appeared in the journal ACS Nano, proposes that nanotubes poke holes in the seeds, which allows water to seep in and speeds up germination. However, some researchers are skeptical that a complex process like germination can be enhanced simply by poking holes in the seed’s coating, and at least one researcher is suggesting that the nanotubes cause a hormonal imbalance in the plants.

Before nanotubes could become a commercial fertilizer, their effect on the environment would have to be studied, with close attention to how nanotubes move through the food chain. Some single-walled nanotubes are toxic to some insects; testing on mice has found multi-layer nanotubes (like the kind used in the study) have carcinogenic effects similar to those of asbestos [Popular Science].

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Image: flickr / wit

In a doctor’s office in the near future, part of a smoker’s routine checkup could involve blowing into a tube connected to a small sensor. The doctor will look at the sensor’s display and know immediately whether she has to deliver the grim diagnosis: lung cancer. Researchers in Israel have invented a new “breathalyzer” that can detect chemical compounds produced by lung cancer cells. The finished device should be portable and inexpensive and provide a faster, easier, and more sensitive way to screen for tumours than X-rays or blood tests. Such screening should help doctors detect cancer early, when it’s most treatable [Telegraph].

The new device, described in Nature Nanotechnology, is not the first to find evidence of cancer on a person’s breath. Other attempts to do this have yielded promising results, … but those devices require a higher concentration of the telltale biomarker chemicals than the Israeli device. The chemicals, called volatile organic compounds (VOCs), are metabolic products present in the vapors that we breathe out, but they occur in such small amounts that researchers have had to find ways to increase their concentrations before testing [Technology Review]. But the new sensor has such sensitivity that it can detect traces of the compound in their natural concentrations in human breath, and it can therefore give results immediately, without processing and analyzing the sample in a lab.

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In the first known case that appears to link nanoparticles to health problems in humans, seven women fell ill after working with paint containing the particles at a factory in China, and two later died, according to an article in the European Respiratory Journal. However, some other experts debate the paper’s conclusions, saying that more mundane toxic materials are to blame.

The women developed itchy eruptions on their arms and faces, along with breathing problems, after working without proper protection at a factory producing paint that contains nanoparticles, which can be as tiny as one-billionth of a meter, or one nanometer. The women were all found to have ball-like collections of immune cells in the lining of the lung that form when the immune system is unable to remove a foreign body. They also had excessive, discoloured fluid in the lung lining. Particles around 30 nanometres in diameter were found in lung fluid and tissue [Nature News]. Sporadically used cotton gauze masks were the only protection the women wore during the five to 13 months they worked spraying paint on polystyrene boards in an unventilated room, and it’s likely they breathed in smoke and fumes. Once the factory was closed, no additional workers fell ill.

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The next big leap in computing power may come from a surprising source: the genetic code. Researchers at IBM have found a way to use DNA strands as the scaffolding on which to place carbon nanotubes, creating tiny microchips that could eventually be more efficient and cheaper to produce than today’s silicon chips. To keep pace with Moore’s Law, which postulates that the number of transistors on an integrated circuit will double every two years, chip makers have to squeeze an increasing number of transistors onto every chip [Wired.com]. The new process offers an entirely different route to miniaturization.

Microchips are used in computers, cell phones and other electronic devices…. Right now, the tinier the chip, the more expensive the equipment. [An IBM spokesman] said that if the DNA origami process scales to production-level, manufacturers could trade hundreds of millions of dollars in complex tools for less than a million dollars of polymers, DNA solutions, and heating implements [Reuters].

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