The US Air Force Research Laboratory (AFRL) has developed a new form of liquid metal with very strange conductive properties. Usually, when a flexible, conductive material is stressed or stretched, its electrical conductivity drops and resistance increases when it's stress or stretched. Just the opposite, Air Force's novel "Polymerized Liquid Metal Networks... can be strained up to 700%, autonomously respond to that strain to keep the resistance between those two states virtually the same, and still return to their original state." The researchers published their results in the scientific journal Advanced Materials. From the Air Force:
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It is all due to the self-organized nanostructure within the material that performs these responses automatically.
“This response to stretching is the exact opposite of what you would expect,” said Dr. Christopher Tabor, AFRL lead research scientist on the project. “Typically a material will increase in resistance as it is stretched simply because the current has to pass through more material. Experimenting with these liquid metal systems and seeing the opposite response was completely unexpected and frankly unbelievable until we understood what was going on.”
Wires maintaining their properties under these different kinds of mechanical conditions have many applications, such as next-generation wearable electronics. For instance, the material could be integrated into a long-sleeve garment and used for transferring power through the shirt and across the body in a way that bending an elbow or rotating a shoulder won’t change the power transferred.
While researchers have demonstrated electronic "tattoos" that can be applied to the skin, Duke University electrical engineers have shown that electronic components can be printed directly onto the body. Typically, printable electronics need post-processing to function but the Duke researchers used an aerosol jet printer to print silver nanowire ink at near room temperature and the circuits worked immediately. On the first try, the traces connected a battery to an LED that glowed. The skin circuits wash right off with soap and water. From IEEE Spectrum
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Flexible electronics are having a moment. The sheer range of devices developed recently demonstrates the scope and speed of the field, including patches to communicate with robots, wearables to reverse baldness or detect heartbeats, and solar cells that can be sewn into clothing....
In two recent papers, Franklin, Williams and colleagues at Duke demonstrate a low-temperature technique for printing electrical components—including leads and transistors—onto delicate surfaces such as apples, human skin and paper, with no post-processing required.
“Ultimately it doesn’t matter if it’s paper or plastic or what-not, you want to be able to put your surface in, add printed, functional electronics to that surface, and away you go,” says (electrical engineer Aaron) Franklin. The new technique enables researchers to print electronic components onto a wide range of materials and reduces overall production complexity and time, he says...
“We don’t want to just print conductive traces onto human skin,” says Franklin. “We want to actually show we can do a full printing on any surface with useful, functional biosensing devices.”
For more than two decades, researchers have explored using DNA as a chemical computer. Until now though, DNA computers have only been capable of solving whatever mathematical problem they were built to tackle. Now though, researchers have demonstrated a more general-purpose DNA computer that can run a variety of chemical "programs." From Caltech
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"Think of them as nano apps," says Damien Woods, professor of computer science at Maynooth University near Dublin, Ireland, and one of two lead authors of the study. "The ability to run any type of software program without having to change the hardware is what allowed computers to become so useful. We are implementing that idea in molecules, essentially embedding an algorithm within chemistry to control chemical processes."
The system works by self-assembly: small, specially designed DNA strands stick together to build a logic circuit while simultaneously executing the circuit algorithm. Starting with the original six bits that represent the input, the system adds row after row of molecules—progressively running the algorithm. Modern digital electronic computers use electricity flowing through circuits to manipulate information; here, the rows of DNA strands sticking together perform the computation. The end result is a test tube filled with billions of completed algorithms, each one resembling a knitted scarf of DNA, representing a readout of the computation. The pattern on each "scarf" gives you the solution to the algorithm that you were running. The system can be reprogrammed to run a different algorithm by simply selecting a different subset of strands from the roughly 700 that constitute the system.
Chinese nanotechnologists injected tiny particles into the eyes of mice resulting in the rodents demonstrating "infrared 'night vision'" that lasted for months. According to nanoscientist Tian Xue and colleagues the University of Science and Technology of China, the technology could eventually help those with certain kinds of color blindness and "provide the potential for close integration within the human body to extend the visual spectrum." From New Scientist:
Like humans, mice cannot perceive light with a wavelength longer than 700 nanometres, which is at the red end of the visible spectrum. But the nanoparticles absorb light with longer – infrared – wavelengths and convert it into shorter wave light that retinal cells can detect. This converted light peaks at a wavelength of 535 nanometres, so the mice see infrared light as green...
Some mice did develop cloudy corneas after the injection, but this disappeared within a fortnight and occurred at similar rates to those in the control group. The team found no other evidence of damage to the mice’s eyes two months after the experiment.
The researchers published their findings in the scientific journal Cell: "Mammalian Near-Infrared Image Vision through Injectable and Self-Powered Retinal Nanoantennae"
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MIT nanotechnologists fabricated microscopic chemical sensors that can be sprayed as an aerosol to monitor pollution, detect chemical leaks, or even ingested as a medical nasal spray. Each sensor chip is 110 micrometers across, about the width of a single human hair, just 1 micrometer thick, and powered by ambient light. From Science News
Right now, researchers can determine whether their sensors have come in contact with certain particles only after the fact — by collecting the chips and hooking them up to electrodes. These electrodes test how easily electric current flows through a chip’s chemical detector, which reveals whether it touched a particular chemical after it was sprayed. But future sensors could emit light signals when in contact with target particles, says study coauthor Michael Strano, a chemical engineer at MIT....
Unlike silicon-based devices that might pose environmental or health hazards, the polymers and the minute amounts of 2-D materials used to make the new devices are expected to be more biofriendly, (says researcher Kourosh Kalantar-Zadeh).
"Colloidal nanoelectronic state machines based on 2D materials for aerosolizable electronics" (Nature Nanotechnology) Read the rest
A team led by Jean-Yves Rauch at FEMTO-ST demonstrated the μRobotex nanofactory's capabilities by building a tiny origami house from silica membranes. Read the rest
Researchers demonstrated a prototype "fire alarm wallpaper" that's meant to be flame-resistant while also integrating a nanotechnology-based sensor that triggers a siren and warning lights. Ying-Jie Zhu at the Chinese Academy of Sciences and colleagues published their work in the journal ACS Nano.
The new wallpaper is based on hydroxyapatite, which is the primary inorganic component of bone and teeth. Although hydroxyapatite is typically brittle and inflexible, in previous work the researchers found that forming ultralong nanowires made of hydroxyapatite gives the material a high flexibility suitable for making wallpaper.
In order to make the nonflammable wallpaper a "smart material" capable of automatically sounding an alarm in response to a fire, the researchers incorporated an ink-based thermosensitive sensor onto the wallpaper.
The thermosensitive sensor is fabricated on the surface of the wallpaper by a simple drop-casting process using an ink containing graphene oxide. The tiny sensor is placed on the backside of the fire- resistant wallpaper so that it is out of sight and protected by the fireproof wallpaper.
The sensor is composed primarily of graphene oxide, which is electrically insulating at room temperature. However, when exposed to heat, the oxygen-containing groups are removed, making the material highly conductive. The sensor is connected to an alarm, so when a fire occurs and the sensor begins to conduct electricity, it causes the alarm to go off.
"Fire alarm wallpaper detects, resists, and warns of house fires
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Researchers demonstrated single-molecule nanomachines that can target diseased cells and then kill them by drilling through the cell membrane. Developed by a team at Rice University, Durham University (UK), and North Carolina State University, the single-molecule nanomotors are about one-billionth of a meter wide and spin at 2 to 3 million rotations per second. They're activated by ultraviolet light and could also be used to deliver drug treatment into the cells. From Rice:
“These nanomachines are so small that we could park 50,000 of them across the diameter of a human hair, yet they have the targeting and actuating components combined in that diminutive package to make molecular machines a reality for treating disease,” Tour said...
The researchers found it takes at least a minute for a motor to tunnel through a membrane. “It is highly unlikely that a cell could develop a resistance to molecular mechanical action,” Tour said.
Pal expects nanomachines will help target cancers like breast tumors and melanomas that resist existing chemotherapy. “Once developed, this approach could provide a potential step change in noninvasive cancer treatment and greatly improve survival rates and patient welfare globally,” he said...
The Pal lab at Durham tested motors on live cells, including human prostate cancer cells. Experiments showed that without an ultraviolet trigger, motors could locate specific cells of interest but stayed on the targeted cells’ surface and were unable to drill into the cells. When triggered, however, the motors rapidly drilled through the membranes.
"Molecular machines open cell membranes" (Nature)
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Researchers from the Technical University of Denmark demonstrated a new nanotechnology-based printing technique that produces long-lasting color images on plastic at resolutions up to 127,000 dots per inch, many times more detailed than traditional laser printers. The system uses a laser to alter the structure of nanoscale structures on the plastic material. (A nanometer is one-billionth of a meter; a human hair is around 60,000 nanometers in diameter.) The nanoprinting technique could also lead to new kinds of 3D displays or invisible watermarks. From New Scientist:
The surface of the plastic is shaped so that it has lots of tiny pillars, one roughly every 200 nanometers. A thin film of the element germanium is then spread over the plastic. Heat from a laser melts the germanium on each pillar, morphing its shape and thickness. As a result, it reflects a specific color. The coating protects the shapes of the newly carved nanostructures.
Resonant laser printing of structural colors on high-index dielectric metasurfaces (ScienceAdvances) Read the rest
The graphene temporary tattoo seen here is the thinnest epidermal electronic device ever and according to the University of Texas at Austin researchers who developed it, the device can take some medical measurements as accurately as bulky wearable sensors like EKG monitors. From IEEE Spectrum:
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Graphene’s conformity to the skin might be what enables the high-quality measurements. Air gaps between the skin and the relatively large, rigid electrodes used in conventional medical devices degrade these instruments’ signal quality. Newer sensors that stick to the skin and stretch and wrinkle with it have fewer airgaps, but because they’re still a few micrometers thick, and use gold electrodes hundreds of nanometers thick, they can lose contact with the skin when it wrinkles. The graphene in the Texas researchers’ device is 0.3-nm thick. Most of the tattoo’s bulk comes from the 463-nm-thick polymer support.
The next step is to add an antenna to the design so that signals can be beamed off the device to a phone or computer, says (electrical engineer Deji) Akinwande.
A team of Israeli scientists devised a system by which a person can use their thoughts alone to trigger tiny DNA-based nanorobots inside a living creature to release a drug.
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University of California San Diego nanoengineers developed a flexible, wearable sensor that measures the blood alcohol level of its wearer and transmits the info to a mobile device. From UCSD News:
The device consists of a temporary tattoo—which sticks to the skin, induces sweat and electrochemically detects the alcohol level—and a portable flexible electronic circuit board, which is connected to the tattoo by a magnet and can communicate the information to a mobile device via Bluetooth.
The device could be integrated with a car’s alcohol ignition interlocks, or friends could use it to check up on each other before handing over the car keys, he added.
“When you’re out at a party or at a bar, this sensor could send alerts to your phone to let you know how much you’ve been drinking,” said Jayoung Kim, a materials science and engineering PhD student.
"Noninvasive Alcohol Monitoring Using a Wearable Tattoo-Based Iontophoretic-Biosensing System" (ACS Sensors)
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University of Cambridge researchers have built the world's smallest working engine. The device, powered by light, could be the basis of future nanoscale machines that are just billionths of a meter in size. Fantastic Voyage, here we come! From the University of Cambridge:
The prototype device is made of tiny charged particles of gold, bound together with temperature-responsive polymers in the form of a gel. When the ‘nano-engine’ is heated to a certain temperature with a laser, it stores large amounts of elastic energy in a fraction of a second, as the polymer coatings expel all the water from the gel and collapse. This has the effect of forcing the gold nanoparticles to bind together into tight clusters. But when the device is cooled, the polymers take on water and expand, and the gold nanoparticles are strongly and quickly pushed apart, like a spring. The results are reported in the journal PNAS.
“It’s like an explosion,” said Dr Tao Ding from Cambridge’s Cavendish Laboratory, and the paper’s first author. “We have hundreds of gold balls flying apart in a millionth of a second when water molecules inflate the polymers around them.”
“We know that light can heat up water to power steam engines,” said study co-author Dr Ventsislav Valev, now based at the University of Bath. “But now we can use light to power a piston engine at the nanoscale.”
"Little ANTs: researchers build the world’s tiniest engine" (Thanks, Brad Wieners!)
"Light-induced actuating nano transducers" (PNAS) Read the rest
For more than two decades, nonscientists and engineers have made molecular-scale motor, switches, propellers, ratchets, and even the "nanocar" above that rolls when its metal "road" is heated. But what can we actually do with these things? The journal Nature looks at today's efforts to develop useful applications for molecular machines, from drug delivery systems inside the body to a new kind of high-density molecular memory for computers. Read the rest
Back in 2006, I had an epiphany. Stories are empathy engines, regardless of the medium. And for humans, they always have been. We’ve been primed to imagine other’s lives since we sat in a cave, telling the stories of our tribe and making sense of the world around us. I published an academic paper on this in 2008 and have given talks about storytelling and empathy ever since. I’m thrilled that there are now hundreds of researchers around the world searching for the neurological mechanisms that link “theory of mind networks” to empathy and narratives.
PJ Manney's (R)evolution is available from Amazon.
In addition, I’ve been a futureholic throughout my life. Whether through science fact or fiction, I’ve wanted to know what was coming and how it might change everything we know. The future is very heady, complex stuff, and difficult to communicate to those who aren’t on your metaphorical wavelength, since change is inherently hard to understand or accept. With my novel, (R)evolution, I felt it was important to share research on nanotechnology and cognitive technologies like brain-computer interfaces, nanomedicine and more with an audience that might not read SF or know what is coming.
My parents are my sample audience. My father is a huge SF fan and the reason I am, too. Future-shorthand is easy with him. But my mother is so ignorant of SF, when we visited Industrial Light and Magic in 1980, she hadn’t seen Star Wars (and still hasn’t) and didn’t recognize the Yoda puppet! Read the rest
This is a flexible mesh circuitry that Harvard nanotechnologists have injected via syringe into the heads of live mice to test a new way of monitoring brain signals from the inside. Read the rest
A German startup called Nanoscribe says it will ship a nanoscale 3D printer in the second quarter of 2013, and that its device will run 100 times faster than similar devices currently in the market:
The technology behind most 3-D microprinters is called two-photon polymerization. It involves focusing tiny, ultrashort pulses from a near-infrared laser on a light-sensitive material. The material polymerizes and solidifies at the focused spots. As the laser beam moves in three dimensions, it creates a 3-D object.
Today’s printers, including Nanoscribe’s present system, keep the laser beam fixed and move the light-sensitive material along three axes using mechanical stages, which slows down printing. To speed up the process, Nanoscribe’s new tool uses a tiny moving mirror to reflect the laser beam at different angles. Thiel says generating multiple light beams with a microlens array could make the process even faster.
The smallest features that can be created using the Nanoscribe printer measure about 30 nanometers, says Julia Greer, professor of materials science at the California Institute of Technology.
Micro 3-D Printer Creates Tiny Structures in Seconds [Prachi Patel/MIT Technology Review]
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