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Scientist grows uniform array of cadmium telluride nanowires

Scientist grows uniform array of cadmium telluride nanowires | Amazing Science | Scoop.it
A researcher from Missouri University of Science and Technology has developed a new way to grow nanowire arrays with a determined diameter, length and uniform consistency. This approach to growing nanomaterials will improve the efficiency of various devices including solar cells and fuel cells.


These semiconducting nanowires could also replace thin films that cover today's solar panels. Current panels can process only 20 percent of the solar energy they take in. By applying the nanowires, the surface area of the panels would increase and allow more efficient solar energy capture and conversion. The wires could also be applied in the biomedical field to maximize heat production in hyperthermia treatment of cancer.


In fuel cells, these nanowire arrays can be used to lower production expenses by relying on more cost-efficient catalysts. "My team and I hope to replace or outperform the current use of platinum and show that these nanowire arrays are better catalysts for the oxygen reduction reactions in the cells," says Dr. Manashi Nath, assistant professor of chemistry at Missouri S&T.


The nanowires, which are grown on patterned nanoelectrodes, are visible only through an electron microscope. Nath creates the nanowire arrays through a process that she calls confined electrodeposition on lithographically patterned nanoelectrodes.


To grow the nanowires, Nath writes an image file that creates a pattern for the shape and size she wants to produce. Using electron beam lithography, she then "stamps" the pattern onto a polymer matrix and the nanowires are grown by applying electric current through electrodeposition.


Nath grows the nanowires in a parallel pattern, which resembles a series of nails protruding from a piece of lumber. One end is held secure to a metal conductor like copper or gold, while the other end spikes outward. The entire structure is surrounded by a polymer matrix. Nath and her research team can produce wires of any shape or size. To increase the nanowires' surface area, Nath can make them hollow in the middle, much like carbon nanotubes found in optics and electronics.

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Google X project plans to use magnetic nanoparticles and wearable sensor to detect diseases

Google X project plans to use magnetic nanoparticles and wearable sensor to detect diseases | Amazing Science | Scoop.it

Google announced a new “Nanoparticle Platform” project Tuesday to develop medical diagnostic technology using nanoparticles, Andrew Conrad, head of the Google X Life Sciences team, disclosed at The Wall Street Journal’s WSJD Live conference. The idea is to use nanoparticles with magnetic cores circulating in the bloodstream with recognition molecules to detect cancer, plaques, or too much sodium, for example.


There are a number of similar research projects using magnetic (and other) nanoparticles in progress, as reported onKurzweilAI. What’s new in the Google project is delivering nanoparticles to the bloodstream via a pill and using a wearable wrist detector to detect the nanoparticles’ magnetic field and read out diagnostic results.


But this is an ambitious moonshot project. “Google is at least five to seven years away from a product approved for use by doctors,” said Sam Gambhir, chairman of radiology at Stanford University Medical School, who has been advising Dr. Conrad on the project for more than a year, the WSJ reports.


“Even if Google can make the system work, it wouldn’t immediately be clear how to interpret the results. That is why Dr. Conrad’s team started the Baseline study [see “New Google X Project to look for disease and health patterns in collected data”], which he hopes will create a benchmark for comparisons.”

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First large DNA crystals generated which could create revolutionary nanodevices

First large DNA crystals generated which could create revolutionary nanodevices | Amazing Science | Scoop.it

DNA has garnered attention for its potential as a programmable material platform that could spawn entire new and revolutionary nanodevices in computer science, microscopy, biology, and more. Researchers have been working to master the ability to coax DNA molecules to self assemble into the precise shapes and sizes needed in order to fully realize these nanotechnology dreams.


For the last 20 years, scientists have tried to design large DNA crystals with precisely prescribed depth and complex features — a design quest just fulfilled by a team at Harvard's Wyss Institute for Biologically Inspired Engineering. The team built 32 DNA crystals with precisely–defined depth and an assortment of sophisticated three–dimensional (3D) features, an advance reported in Nature Chemistry.


The team used their "DNA–brick self–assembly" method, which was first unveiled in a 2012 Science publication when they created more than 100 3D complex nanostructures about the size of viruses. The newly–achieved periodic crystal structures are more than 1000 times larger than those discrete DNA brick structures, sizing up closer to a speck of dust, which is actually quite large in the world of DNA nanotechnology.


"We are very pleased that our DNA brick approach has solved this challenge," said senior author and Wyss Institute Core Faculty member Peng Yin, Ph.D., who is also an Associate Professor of Systems Biology at Harvard Medical School, "and we were actually surprised by how well it works."


Scientists have struggled to crystallize complex 3D DNA nanostructures using more conventional self–assembly methods. The risk of error tends to increase with the complexity of the structural repeating units and the size of the DNA crystal to be assembled.


The DNA brick method uses short, synthetic strands of DNA that work like interlocking Lego® bricks to build complex structures. Structures are first designed using a computer model of a molecular cube, which becomes a master canvas. Each brick is added or removed independently from the 3D master canvas to arrive at the desired shape — and then the design is put into action: the DNA strands that would match up to achieve the desired structure are mixed together and self assemble to achieve the designed crystal structures.


"Therein lies the key distinguishing feature of our design strategy–its modularity," said co–lead author Yonggang Ke, Ph.D., formerly a Wyss Institute Postdoctoral Fellow and now an assistant professor at the Georgia Institute of Technology and Emory University. "The ability to simply add or remove pieces from the master canvas makes it easy to create virtually any design."


The modularity also makes it relatively easy to precisely define the crystal depth. "This is the first time anyone has demonstrated the ability to rationally design crystal depth with nanometer precision, up to 80 nm in this study," Ke said. In contrast, previous two–dimensional DNA lattices are typically single–layer structures with only 2 nm depth.


"DNA crystals are attractive for nanotechnology applications because they are comprised of repeating structural units that provide an ideal template for scalable design features", said co–lead author graduate student Luvena Ong.


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New Omnidirectional Broadband 2D Crystal Efficiently Absorbs 85% Of Photon Energy

New Omnidirectional Broadband 2D Crystal Efficiently Absorbs 85% Of Photon Energy | Amazing Science | Scoop.it

Research engineers at MIT have developed a novel solar material in the form of a 2D metallic, dielectric photonic crystal.  The material has remarkable properties of broadband absorption of sunlight, from visible to near infrared portions of the spectrum, with little dependence on the angle of the incident light.  Efficiencies in these bands were measured to be 85% absorption of photons.

The material also withstands temperatures up to 1000 degrees Celsius, making it suitable to act as the material for a collector of concentrated sunlight.  Experiments show that the absorption is governed by the nanocavities.  Tuning the absorption bands is accomplished simply by varying the radii and depths of the cavities.


The new material works as a part of the solar-thermophotovoltaic (STPV) device in which incident solar radiation is converted to infrared, heat energy, causing the material to emit light that is in turn converted to electrical energy.   Earlier STPV devices contained nanocavities but were hollow and not filled with a dielectric.  According to the primary author, “They were empty, there was air inside.  No one had tried putting a dielectric material inside, so we tried that and saw some interesting properties.”  A dielectric is a material which responds to electric fields by shielding or attenuating it via non-mobile charges, in contrast to a conductor which shields by rearrangement of electrons.


The cavities are sized in the right way such that there is a rich and complex absorption mode structure perfect for relevant wavelengths.  “You can tune the absorption just by changing the size of the nanocavities,” said Dr. Chou.


Importantly, the new material is compatible with many kinds of existing manufacturing technologies.  The lead author Dr. Chou said “This is the first-ever device of this kind that can be fabricated with a method based on current techniques, which means it’s able to be manufactured on silicon wafer scales.”


Prior work on similar materials were restricted in size to making devices that span only a few inches.  The new cavity material is both cheaper and easier to process.

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Casting Custom-Shaped Inorganic Structures with DNA Molds

Casting Custom-Shaped Inorganic Structures with DNA Molds | Amazing Science | Scoop.it
Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University have unveiled a new method to form tiny 3D metal nanoparticles in prescribed shapes and dimensions using DNA, Nature's building block, as a construction mold.

The ability to mold inorganic nanoparticles out of materials such as gold and silver in precisely designed 3D shapes is a significant breakthrough that has the potential to advance laser technology, microscopy, solar cells, electronics, environmental testing, disease detection and more.

"We built tiny foundries made of stiff DNA to fabricate metal nanoparticles in exact three–dimensional shapes that we digitally planned and designed," said Peng Yin, senior author of the paper, Wyss Core Faculty member and Assistant Professor of Systems Biology at Harvard Medical School.


The Wyss team's findings, described in a paper titled "Casting Inorganic Structures with DNA Molds," were published today in Science. The work was done in collaboration with MIT's Laboratory for Computational Biology and Biophysics, led by Mark Bathe, senior co–author of the paper.


"The paper's findings describe a significant advance in DNA nanotechnology as well as in inorganic nanoparticle synthesis," Yin said. For the very first time, a general strategy to manufacture inorganic nanoparticles with user-specified 3D shapes has been achieved to produce particles as small as 25 nanometers or less, with remarkable precision (less than 5 nanometers). A sheet of paper is approximately 100,000 nanometers thick.


The 3D inorganic nanoparticles are first conceived and meticulously planned using computer design software. Using the software, the researchers design three–dimensional "frameworks" of the desired size and shape built from linear DNA sequences, which attract and bind to one another in a predictable manner.


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World's first "solar battery" runs on light and air and stores its own power

World's first "solar battery" runs on light and air and stores its own power | Amazing Science | Scoop.it

Researchers at The Ohio State University have invented a solar battery -- a combination solar cell and battery -- which recharges itself using air and light. The design required a solar panel which captured light, but admitted air to the battery. Here, scanning electron microscope images show the solution: nanometer-sized rods of titanium dioxide (larger image) which cover the surface of a piece of titanium gauze (inset). The holes in the gauze are approximately 200 micrometers across, allowing air to enter the battery while the rods gather light. Image courtesy of Yiying Wu, The Ohio State University.


When the battery discharges, it chemically consumes oxygen from the air to re-form the lithium peroxide. An iodide additive in the electrolyte acts as a “shuttle” that carries electrons, and transports them between the battery electrode and the mesh solar panel. The use of the additive represents a distinct approach on improving the battery performance and efficiency, the team said.


The mesh belongs to a class of devices called dye-sensitized solar cells, because the researchers used a red dye to tune the wavelength of light it captures.


In tests, they charged and discharged the battery repeatedly, while doctoral student Lu Ma used X-ray photoelectron spectroscopy to analyze how well the electrode materials survived—an indication of battery life.


First they used a ruthenium compound as the red dye, but since the dye was consumed in the light capture, the battery ran out of dye after eight hours of charging and discharging—too short a lifetime. So they turned to a dark red semiconductor that wouldn’t be consumed: hematite, or iron oxide—more commonly called rust.


Coating the mesh with rust enabled the battery to charge from sunlight while retaining its red color. Based on early tests, Wu and his team think that the solar battery’s lifetime will be comparable to rechargeable batteries already on the market.


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'Invisibility cloak' uses lenses to bend light, effectively rendering things invisible to the eye

'Invisibility cloak' uses lenses to bend light, effectively rendering things invisible to the eye | Amazing Science | Scoop.it
A device called the Rochester Cloak uses an array of lenses to bend light, effectively rendering what is on the other side invisible to the eye. And you can try it for yourself.


One of the problems with the cloaking devices developed to date -- and it's a big one -- is that they really only work if both the viewer and whatever is being cloaked remain still. This, of course, is not entirely practical, but a difficult problem to solve.


For the first time, researchers have made a cloaking device that works multi-directionally in three dimensions -- using no specialized equipment, but four standard lenses.


"There've been many high tech approaches to cloaking and the basic idea behind these is to take light and have it pass around something as if it isn't there, often using high-tech or exotic materials," said professor of physics at Rochester University John Howell, who developed the Rochester Cloak with graduate student Joseph Choi.


"This is the first device that we know of that can do three-dimensional, continuously multidirectional cloaking, which works for transmitting rays in the visible spectrum," Choi added.


As well as at least partially solving the viewpoint problem, the Rochester cloak also leaves the background undisturbed, without any warping, as has appeared in other devices. This invisibility has a range of around 15 degrees; as you can see in the video below at around the two-minute mark when Choi places his hand in between the lenses, the dead centre of the field is not included.


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Artificial membranes form bio-silicon interfaces

Artificial membranes form bio-silicon interfaces | Amazing Science | Scoop.it

A group of scientists in Chile has created* artificial biomembranes, mimicking those found in living organisms on silicon surfaces, a step toward creating bio-silicon interfaces, where biological “sensor” molecules can be printed onto a cheap silicon chip with integrated electronic circuits.


Described in The Journal of Chemical Physics from AIP Publishing, the artificial membranes have potential applications such as detecting bacterial contaminants in food, toxic pollution in the environment, and dangerous diseases .


The idea is to create a “biosensor that can transmit electrical signals through the membrane,” said María José Retamal, a Ph.D. student at Pontificia Universidad Católica de Chile and first author of the paper.


Lipid membranes separate distinct spaces within cells and define walls between neighboring cells — a functional compartmentalization that serves many physiological processes, protecting genetic material, regulating what comes in and out of cells, and maintaining the function of separate organs.


Synthetic membranes that mimic nature offer the possibility of containing membrane proteins — biological molecules that could be used for detecting toxins, diseases and many other biosensing applications.


More work is needed to standardize the process by which proteins are to be inserted in the membranes, to define the mechanism by which an electrical signal would be transmitted when a protein binds its target, and to calibrate how that signal is detected by the underlying circuitry, Retamal said.

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* Retamal and her colleagues created the first artificial membrane without using solvents on a silicon support base. They chose silicon because of its low cost, wide availability and because its “hydrophobicity” (how much it repels water) can be controlled chemically, allowing them to build membranes on top.


Next they evaporated a chemical known as chitosan onto the silicon. Chitosan is derived from chitin, a sugar found in the shells of certain crustaceans, like lobsters or shrimp. Whole bags of the powder can be bought from chemical companies worldwide. They chose this ingredient for its ability to form a moisturizing matrix. It is insoluble in water, but chitosan is porous, so it is capable of retaining water.


Finally they evaporated a phospholipid molecule known as dipalmitoylphosphatidylcholine (DPPC) onto the chitosan-covered silicon substrate and showed that it formed a stable “bilayer,” the classic form of a membrane. Spectroscopy showed that these artificial membranes were stable over a wide range of temperatures.

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An Autonomous, Optoelectronic Camouflage Material Inspired By Octopus Skin

An Autonomous, Optoelectronic Camouflage Material Inspired By Octopus Skin | Amazing Science | Scoop.it

An interdisciplinary team of scientists and engineers has developed a thin, flexible 4-layer material that autonomously camouflages itself to the surroundings by optically evaluating the background and changing its pattern to match much like how the skin of an octopus or chameleon does so in the wild.  The system mimics different patterns of background quickly within 1 to 2 seconds.  To date there has been no other similar system which includes the crucial capabilities of sensing and actuation in a distributed manner.


The inspiration for this creation came from understanding of the skin of cephalopods (examples of which include octopus, squid, cuttlefish etc.), sea creatures that mimic in full color and with greater resolution the appearance of their environment.  Celphalopod skin has faster response times, from 250-750 milliseconds.  The prototype material is much simpler, arranged as an array of 16 x 16 relatively large, 1 mm square “pixels” that change from black to white and back again.


Response times are slower too in the 1 to 2 second range.

There is no overall camera system to detect the background and no central processing that controls the patterning of the material. In real octopuses, the eyes are involved, but the skin has its own photoreceptors similar to those found in the retina.  The designed layered material works in the latter, distributed way, by integrating distributed optical sensors that monitor its surroundings and then commanding independent optical “actuators” to adapt dynamically.

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Artificial cells take their first steps: Movable cytoskeleton membrane fabricated for the first time

Artificial cells take their first steps: Movable cytoskeleton membrane fabricated for the first time | Amazing Science | Scoop.it

Using only a few ingredients, the biophysicist Prof. Andreas Bausch and his team at the Technische Universität München (TUM) have successfully implemented a minimalistic model of the cell that can change its shape and move on its own. They describe how they turned this goal into reality in the current edition of the academic journal Science, where their research is featured as cover story.

Cells are complex objects with a sophisticated metabolic system. Their evolutionary ancestors, the primordial cells, were merely composed of a membrane and a few molecules. These were minimalistic yet perfectly functioning systems.


Thus, "back to the origins of the cell" became the motto of the group of TUM-Prof. Andreas Bausch, who is member of the cluster of excellence "Nanosystems Initiative Munich (NIM)"  and his international partners. Their dream is to create a simple cell model with a specific function using a few basic ingredients. In this sense they are following the principle of synthetic biology in which individual cellular building blocks are assembled to create artificial biological systems with new characteristics.


The vision of the biophysicists was to create a cell-like model with a biomechanical function. It should be able to move and change its shape without external influences. They explain how they achieved this goal in their latest publication in Science.


The biophysicists’ model comprises a membrane shell, two different kinds of biomolecules and some kind of fuel. The envelope, also known as a vesicle, is made of a double-layered lipid membrane, analogous of natural cell membranes. The scientists filled the vesicals with microtubules, tube-shaped components of the cytoskeleton, and kinesin molecules. In cells, kinesins normally function as molecular motors that transport cellular building blocks along the microtubules. In the experiment, these motors permanently push the tubules alongside each other. For this, kinesins require the energy carrier ATP, which was also available in the experimental setup.


From a physical perspective, the microtubules form a two-dimensional liquid crystal under the membrane, which is in a permanent state of motion. "One can picture the liquid crystal layer as tree logs drifting on the surface of a lake," explains Felix Keber, lead author of the study. "When it becomes too congested, they line up in parallel but can still drift alongside each other."


Decisive for the deformation of the artificial cell construction is that, even in its state of rest, the liquid crystal must always contain faults. Mathematicians explain these kinds of phenomena by way of the Poincaré-Hopf theorem, figuratively also referred to as the "hairy ball problem." Just as one can't comb a hairy ball flat without creating a cowlick, there will always be some microtubules that cannot lay flat against the membrane surface in a regular pattern. At certain locations the tubules will be oriented somewhat orthogonally to each other – in a very specific geometry. Since the microtubules in the case of the Munich researchers are in constant motion alongside each other due to the activity of the kinesin molecules, the faults also migrate. Amazingly, they do this in a very uniform and periodic manner, oscillating between two fixed orientations.

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Introducing the multi-tasking nanoparticle for diagnostic and therapeutic applications

Introducing the multi-tasking nanoparticle for diagnostic and therapeutic applications | Amazing Science | Scoop.it

Kit Lam and colleagues from UC Davis and other institutions have created dynamic nanoparticles (NPs) that could provide an arsenal of applications to diagnose and treat cancer. Built on an easy-to-make polymer, these particles can be used as contrast agents to light up tumors for MRI and PET scans or deliver chemo and other therapies to destroy tumors. In addition, the particles are biocompatible and have shown no toxicity. The study was published online today in Nature Communications.


“These are amazingly useful particles,” noted co-first author Yuanpei Li, a research faculty member in the Lam laboratory. “As a contrast agent, they make tumors easier to see on MRI and other scans. We can also use them as vehicles to deliver chemotherapy directly to tumors; apply light to make the nanoparticles release singlet oxygen (photodynamic therapy) or use a laser to heat them (photothermal therapy) – all proven ways to destroy tumors.”


Jessica Tucker, program director of Drug and Gene Delivery and Devices at the National Institute of Biomedical Imaging and Bioengineering, which is part of the National Institutes of Health, said the approach outlined in the study has the ability to combine both imaging and therapeutic applications in a single platform, which has been difficult to achieve, especially in an organic, and therefore biocompatible, vehicle.


"This is especially valuable in cancer treatment, where targeted treatment to tumor cells, and the reduction of lethal effects in normal cells, is so critical,” she added.


 Though not the first nanoparticles, these may be the most versatile. Other particles are good at some tasks but not others. Non-organic particles, such as quantum dots or gold-based materials, work well as diagnostic tools but have safety issues. Organic probes are biocompatible and can deliver drugs but lack imaging or phototherapy applications.


Built on a porphyrin/cholic acid polymer, the nanoparticles are simple to make and perform well in the body. Porphyrins are common organic compounds. Cholic acid is produced by the liver.


To further stabilize the particles, the researchers added the amino acid cysteine (creating CNPs), which prevents them from prematurely releasing their therapeutic payload when exposed to blood proteins and other barriers. At 32 nanometers, CNPs are ideally sized to penetrate tumors, accumulating among cancer cells while sparing healthy tissue.


In the study, the team tested the nanoparticles, both in vitro and in vivo, for a wide range of tasks. On the therapeutic side, CNPs effectively transported anti-cancer drugs, such as doxorubicin. Even when kept in blood for many hours, CNPs only released small amounts of the drug; however, when exposed to light or agents such as glutathione, they readily released their payloads. The ability to precisely control chemotherapy release inside tumors could greatly reduce toxicity. CNPs carrying doxorubicin provided excellent cancer control in animals, with minimal side effects.

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Eco-friendly ‘pre-fab’ self-assembling nanoparticles could revolutionize nano manufacturing

Eco-friendly ‘pre-fab’ self-assembling nanoparticles could revolutionize nano manufacturing | Amazing Science | Scoop.it

University of Massachusetts Amherst scientists have developed a breakthrough technique for creating water-soluble nano-modules and controlling molecular assembly of nanoparticles over multiple length scales.


The new method should reduce the time nanotech manufacturing firms spend in trial-and-error searches for materials to make electronic devices such as solar cells, organic transistors, and organic light-emitting diodes.


“The old way can take years,” says materials chemist Paul Lahti, co-director with Thomas Russell of UMass Amherst’s Energy Frontiers Research Center (EFRC), supported by the U.S. Department of Energy.


“Another of our main objectives is to make something that can be scaled up from nano- to mesoscale, and our method does that. It is also much more ecologically friendly because we use water instead of dangerous solvents in the process.


“In our recent paper, we worked on glass, but we want to translate to flexible materials and produce roll-to-roll manufactured materials with water,” said chemist Dhandapani Venkataraman, lead investigator. “We expect to actually get much greater efficiency.” He suggests that reaching 5 percent power conversion efficiency would justify the investment for making small, flexible solar panels to power devices such as smart phones.


If the average smart phone uses 5 watts of power and all 307 million United States users switched from batteries to flexible solar, it could save more than 1500 megawatts per year, Venkataraman estimates. “That’s nearly the output of a nuclear power station,” he says, “and it’s more dramatic when you consider that coal-fired power plants generate 1 megawatt and release 2,250 lbs. of carbon dioxide. So if a fraction of the 6.6 billion mobile phone users globally changed to solar, it would reduce our carbon footprint a lot.”


Doctoral student and first author Tim Gehan says that organic solar cells made in this way can be semi-transparent, as well, “so you could replace tinted windows in a skyscraper and have them all producing electricity during the day when it’s needed. And processing is much cheaper and cleaner with our cells than in traditional methods.”

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New microhairs bend in magnetic field, directing water against gravity

New microhairs bend in magnetic field, directing water against gravity | Amazing Science | Scoop.it

MIT engineers have fabricated a new elastic material coated with microscopic, hairlike structures that tilt in response to a magnetic field.

Depending on the field’s orientation, the microhairs can tilt to form a path through which fluid can flow; the material can even direct water upward, against gravity.


Potential uses include waterproofing, anti-glare "smart windows” for buildings and cars, and rain-resistant clothing.


In experiments, the magnetically activated material directed not just the flow of fluid, but also light — much as window blinds tilt to filter the sun. Researchers say the work could lead to waterproofing and anti-glare applications, such as “smart windows” for buildings and cars.


“You could coat this on your car windshield to manipulate rain or sunlight,” says Yangying Zhu, a graduate student in MIT’s Department of Mechanical Engineering. “So you could filter how much solar radiation you want coming in, and also shed raindrops. This is an opportunity for the future.”


In the near term, the material could also be embedded in lab-on-a-chip devices to magnetically direct the flow of cells and other biological material through a diagnostic chip’s microchannels.

Zhu reports the details of the material this month in the journal Advanced Materials.


The inspiration for the microhair array comes partly from nature, Zhu says. For example, human nasal passages are lined with cilia — small hairs that sway back and forth to remove dust and other foreign particles. Zhu sought to engineer a dynamic, responsive material that mimics the motion of cilia.


In principle, more complex magnetic fields could be designed to create intricate tilting patterns throughout an array, say the researchers. Such patterns may be useful in directing cells through a microchip’s channels, or wicking moisture from a windshield. Since the material is flexible, it may even be woven into fabric to create rain-resistant clothing.


Reference:


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Google[x] Reveals Nano Pill To Seek Out Cancerous Cells

Google[x] Reveals Nano Pill To Seek Out Cancerous Cells | Amazing Science | Scoop.it

Detecting cancer could be as easy as popping a pill in the near future. Google’s head of life sciences, Andrew Conrad, took to the stage at the Wall Street Journal Digital conference to reveal that the tech giant’s secretive Google[x] lab has been working on a wearable device that couples with nanotechnology to detect disease within the body.


“We’re passionate about switching from reactive to proactive and we’re trying to provide the tools that make that feasible,” explained Conrad. This is a third project in a series of health initiatives for Google[x]. The team has already developed a smart contact lens that detects glucose levels for diabetics and utensils that help manage hand tremors in Parkinson’s patients.


The plan is to test whether tiny particles coated “magnetized” with antibodies can catch disease in its nascent stages. The tiny particles are essentially programmed to spread throughout the body via pill and then latch on to the abnormal cells. The wearable device then “calls” the nanoparticles back to ask them what’s going on with the body and to find out if the person who swallowed the pill has cancer or other diseases.


“Think of it as sort of like a mini self-driving car,” Conrad simplified with a clear reference to Google[x]‘s vehicular project. “We can make it park where we want it to.” Conrad went on with the car theme, saying the body is more important than a car and comparing our present healthcare system as something that basically only tries to change our oil after we’ve broken down. “We wouldn’t do that with a car,” he added.

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Biomedical Sensors That Dissolve in Your Body and Reduce Infection and Waste

Biomedical Sensors That Dissolve in Your Body and Reduce Infection and Waste | Amazing Science | Scoop.it

John Rogers, a professor of engineering at the University of Illinois at Urbana-Champaign, was the lead author on a recent study published in the journal Advanced Materials. This study tested biodegradable printed circuit boards, a very efficient type of sensor with a large surface area. In the study, Rogers and his team showed they had effectively created a sensor that both does its job and is fully dissolvable.


Rogers spearheads a lab that has been at the forefront of this technology since 2008. When they were first getting started in the field of biodegradable sensors, the researchers spent several years coming up with the materials and processes that worked, Rogers said in an email. “Our research now is focusing on systems and applications, in areas ranging from biomedicine to consumer electronics,” he added.


The semiconductor, the part of the device that does the sensing, is made of two materials. One is extremely thin silicon, which the researchers shave down to the nano scale. They combine the silicon with metals that are familiar components of food and vitamins, like magnesium, zinc, and iron. The sensor is encapsulated by and rests on a set of polymers that, Rogers said, “are already used, for other purposes, in the body.”


Rogers and his team are still perfecting the sensors, but they anticipate that they could even work wirelessly by transmitting information via radio waves back to doctors’ devices. Typically, the silicon dissolves in the body in a few weeks, Rogers said, but different substances could extend the device’s lifespan.


Devices like these have the potential to change medicine for the better. Currently, the infection rate for surgeries—including the procedure needed to implant a biomedical device—is 1 to 3 percent. Usually this happens because the wound gets contaminated.


The logic for Rogers’ devices is simple: when doctors have to cut a person open less often, there’s less chance of infection. And the devices could be used as more than sensors; they could administer programmed drug delivery for conditions that require daily injections, or reduce pain by stimulating stressed nerve endings.


There are also environmental implications. In an effort to decrease the chance of infection, the health industry has relied for years on disposable, one-use devices, from syringes to hospital gowns. The result is that medical facilities generate billions of tons of trash per year, although no one is sure exactly how much. And although much of this trash could be recycled with the proper treatment, almost all of it just ends up in landfills, where it biodegrades very slowly and could present potential health hazards if people are exposed to it. Dissolvable, biodegradable devices would mean less waste in a landfill, and if a device did end up there, it would decompose rapidly.


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Robotically-Controlled Swimming Nanomotors Carve Out Next-Generation Nanoscale Computer Chip Lithographic Features

Robotically-Controlled Swimming Nanomotors Carve Out Next-Generation Nanoscale Computer Chip Lithographic Features | Amazing Science | Scoop.it

University of California San Diego researchers have imagined and realized a low cost, innovative solution to next-generation nanofabrication that could be applied to advanced computer chip creation using tiny nanomotors inspired by biology.  The researchers showed that it is possible to carve out well-defined, nanoscale features such as ridges and trenches in a substrate, basic components of the modern computer chip, by exploiting a clever yet simple suite of technologies to control the nanomotor and etch out nanoscale features.


The Digital Revolution, sometimes called the Third Industrial Revolution, continues unabated today, powered in no small part by the constant, ongoing improvements in computer processor technology.  A key aspect of the technology, at least until the last few years, has been use of photolithography, to generate microscale semiconductor structures that are at the heart of the millions of transistors on each processing chip.  Photolithography relies on a “mask”, a light-sensitive “photo resist” material, and intense light, which together gives rise to controlled, systematic removal of substrate and creation of desired structures on the photo resist.


The production strategy however has run into increasing problems as the scale of the features shrink, due to the engineers’ desire to cram ever more complex features onto one chip.  When the structures of the mask become smaller than the wavelength of the light, diffractive effects become stronger and it is necessary to correct with mathematics.  One solution is to move to shorter wavelengths of light, or to use electrons directly to etch features, but both of these solutions necessitate use of expensive beam sources to generate the requisite high energies.


For these reasons, the results of the nanomotor is highly relevant and exciting.  The nanomotor, in its most basic form, is a gold-platinum rod about the size of a bacterium, 2 microns long by 350 nanometers wide, immersed in a solution of hydrogen peroxide that serves as its “fuel”.  The platinum on the nanomotor naturally catabolizes the hydrogen peroxide and produces excess protons (along with diatomic molecular oxygen) in an asymmetric fashion, with more protons on one end compared to the other.  The proton imbalance propels the nanometer by a constant force motion (there is no gliding due to the low Reynolds number condition in liquid at nanoscales), up to speeds of 15 micrometers per second.


Ferromagnetic nickel is embedded in the nanomotor with North-South orientation directed along its width (the shorter dimension, and therefore parallel to the plane of motion).  A constant field applied perpendicular to the plane over the entire environment breaks isotropic symmetry leading to orientation of the nanomotor.  Since the nanomotor is always moving, repeated reorientation of the magnetic field direction over time leads to well-defined nanomotor paths.

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"Nanograss" boosts the efficiency of organic solar cells

"Nanograss" boosts the efficiency of organic solar cells | Amazing Science | Scoop.it

Solar cells are built using two different types of semiconductors ("p-type" and "n-type"), each with a slightly different composition; when the two come in close contact, they form a so-called "PN junction." This junction is a critical component of any solar cell because it generates an electric field that causes charge inside the cell to flow in a set direction, creating a voltage. Voltage times current equals (solar) power.


After decades of trial and error, scientists now believe that the ideal geometry for a PN junction would consist of a series of vertical nanoscale pillars made from one type of semiconductor (either p- or n-type) and surrounded by a semiconductor of the opposite type. This shape is extremely effective at trapping light without reflecting it, resulting in a greater amount of charge being collected, while also allowing the use of cheaper, lower-grade materials in smaller volumes, which decreases the overall cost of the cell.


This "Holy Grail" structure has already been achieved in inorganic solar cells, but has been elusive for their organic counterpart due to some of the unique challenges they present. Now, however, a team led by Prof. Alejandro Briseno at UMass Amherst has developed a new simple and highly adaptable technique that can produce "nanograss" for use in organic solar cells, which could lead to a significant boost in their efficiency.

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Hybrid materials could smash the solar efficiency ceiling by extracting electrons from dark triplet excitons

Hybrid materials could smash the solar efficiency ceiling by extracting electrons from dark triplet excitons | Amazing Science | Scoop.it
Researchers have developed a new method for harvesting the energy carried by particles known as ‘dark’ spin-triplet excitons with close to 100% efficiency, clearing the way for hybrid solar cells which could far surpass current efficiency limits.


The team, from the University of Cambridge, have successfully harvested the energy of triplet excitons, an excited electron state whose energy in harvested in solar cells, and transferred it from organic to inorganic semiconductors. To date, this type of energy transfer had only been shown for spin-singlet excitons. The results are published in the journal Nature Materials.


In the natural world, excitons are a key part of photosynthesis: light photons are absorbed by pigments and generate excitons, which then carry the associated energy throughout the plant. The same process is at work in a solar cell.


In conventional semiconductors such as silicon, when one photon is absorbed it leads to the formation of one free electron that can be extracted as current. However, in pentacene, a type of organic semiconductor, the absorption of a photon leads to the formation of two electrons. But these electrons are not free and they are difficult to pin down, as they are bound up within ‘dark’ triplet exciton states.

Excitons come in two ‘flavours’: spin-singlet and spin-triplet. Spin-singlet excitons are ‘bright’ and their energy is relatively straightforward to harvest in solar cells. Triplet-spin excitons, in contrast, are ‘dark’, and the way in which the electrons spin makes it difficult to harvest the energy they carry.


“The key to making a better solar cell is to be able to extract the electrons from these dark triplet excitons,” said Maxim Tabachnyk, a Gates Cambridge Scholar at the University’s Cavendish Laboratory, and the paper’s lead author. “If we can combine materials like pentacene with conventional semiconductors like silicon, it would allow us to break through the fundamental ceiling on the efficiency of solar cells.”

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Platinum meets its match in quantum dots from coal

Platinum meets its match in quantum dots from coal | Amazing Science | Scoop.it

Graphene quantum dots created at Rice University grab onto graphene platelets like barnacles attach themselves to the hull of a boat. But these dots enhance the properties of the mothership, making them better than platinum catalysts for certain reactions within fuel cells.


The Rice lab of chemist James Tour created dots known as GQDs from coal last year and have now combined these nanoscale dots with microscopic sheets of graphene, the one-atom-thick form of carbon, to create a hybrid that could greatly cut the cost of generating energy with fuel cells. - See more at: f


The research is the subject of a new paper in the American Chemical Society journal ACS Nano.


The lab discovered boiling down a solution of GQDs and graphene oxide sheets (exfoliated from common graphite) combined them into self-assembling nanoscale platelets that could then be treated with nitrogen and boron. The hybrid material combined the advantages of each component: an abundance of edges where chemical reactions take place and excellent conductivity between GQDs provided by the graphene base. The boron and nitrogen collectively add more catalytically active sites to the material than either element would add alone.


“The GQDs add to the system an enormous amount of edge, which permits the chemistry of oxygen reduction, one of the two needed reactions for operation in a fuel cell,” Tour said. “The graphene provides the conductive matrix required. So it’s a superb hybridization.”

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Ultrasensitive graphene sensor tracks down cancer biomarkers

Ultrasensitive graphene sensor tracks down cancer biomarkers | Amazing Science | Scoop.it
An ultrasensitive biosensor made from the wonder material graphene has been used to detect molecules that indicate an increased risk of developing cancer. The biosensor has been shown to be more than five times more sensitive than bioassay tests currently in use, and was able to provide results in a matter of minutes, opening up the possibility of a rapid, point-of-care diagnostic tool for patients.


The biosensor has been shown to be more than five times more sensitive than bioassay tests currently in use, and was able to provide results in a matter of minutes, opening up the possibility of a rapid, point-of-care diagnostic tool for patients. The biosensor has been presented today, 19 September, in IOP Publishing's journal 2D Materials.


To develop a viable bionsensor, the researchers, from the University of Swansea, had to create patterned graphene devices using a large substrate area, which was not possible using the traditional exfoliation technique where layers of graphene are stripped from graphite.


Instead, they grew graphene onto a silicon carbide substrate under extremely high temperatures and low pressure to form the basis of the biosensor. The researchers then patterned graphene devices, using semiconductor processing techniques, before attaching a number of bioreceptor molecules to the graphene devices. These receptors were able to bind to, or target, a specific molecule present in blood, saliva or urine.


The molecule, 8-hydroxydeoxyguanosine (8-OHdG), is produced when DNA is damaged and, in elevated levels, has been linked to an increased risk of developing several cancers. However, 8-OHdG is typically present at very low concentrations in urine, so is very difficult to detect using conventional detection assays, known as enzyme-linked immunobsorbant assays (ELISAs).


In their study, the researchers used x-ray photoelectron spectroscopy and Raman spectroscopy to confirm that the bioreceptor molecules had attached to the graphene biosensor once fabricated, and then exposed the biosensor to a range of concentrations of 8-OHdG.

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Scientists develop ultra-sensitive biosensor from molybdenite semiconductor material

Scientists develop ultra-sensitive biosensor from molybdenite semiconductor material | Amazing Science | Scoop.it

An atomically thin, two-dimensional, ultrasensitive semiconductor material for biosensing developed by University of California Santa Barbara (UCSB) researchers promises to push the boundaries of biosensing technology in many fields, from health care to environmental protection to forensic industries.


It’s based on molybdenum disulfide, or molybdenite (MoS2), as an alternative to graphene. Molybdenum disulfide — commonly used as a dry lubricant — surpasses graphene’s already high sensitivity, offers better scalability, and lends itself to high-volume manufacturing, the researchers say. Results of their study have been published in ACS Nano.

“This invention has established the foundation for a new generation of ultrasensitive and low-cost biosensors that can eventually allow single-molecule detection — the holy grail of diagnostics and bioengineering research,” said Samir Mitragotri, co-author and professor of chemical engineering and director of the Center for Bioengineering at UCSB.


The key, according to UCSB professor of electrical and computer engineering Kaustav Banerjee, who led this research, is MoS2’s band gap, a characteristic of a material that determines its electrical conductivity, the minimum amount of energy required for conduction; i.e., for an electron to break free of its bound state in a material — the gap between bound and free.


Semiconductor materials have a small but nonzero band gap and can be switched between conductive and insulated states controllably. The larger the band gap, the better its ability to switch states and to insulate leakage current in an insulated state. MoS2’s wide band gap allows current to travel but also prevents leakage and results in more sensitive and accurate readings.


Graphene has attracted wide interest as a biosensor due to its two-dimensional structure (which allows for excellent electrostatic control of the transistor channel by the gate) and its high surface-to-volume ratio. However, the sensitivity of a field-effect transistor (FET) biosensor based on graphene is fundamentally limited by graphene’s zero (fully conductive) band gap, which results in increased leakage current, leading to reduced sensitivity, explained Banerjee, who is also the director of the Nanoelectronics Research Lab at UCSB.


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THE OFFICIAL ANDREASCY's curator insight, September 5, 2014 4:06 AM

Seems like something out of Star Trek.

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Atomically thin molybendum disulfide opens door to high-speed integrated nanophotonic circuits

Atomically thin molybendum disulfide opens door to high-speed integrated nanophotonic circuits | Amazing Science | Scoop.it

Scientists at the University of Rochester and Swiss Federal Institute of Technology in Zurich have devised an experimental circuit consisting of a silver nanowire and a single-layer atomically thin flake of molybendum disulfide (MoS2) — a step toward building computer chips capable of transporting digital information at light speed.


The researchers used a laser to excite electromagnetic waves called plasmons (vibrating electron clouds) at the surface of the wire, causing an MoS2 flake at the far end of the wire to generate strong light emission. MoS2 excitons can also decay into nanowire plasmons, they found.


This interaction an be exploited for creating nanophotonic integrated circuits, said Nick Vamivakas, assistant professor of quantum optics and quantum physics at the University of Rochester and senior author of the paper in the journal Optica.


Photonic devices can be much faster than electronic ones, but they are bulkier and cannot be miniaturized nearly as well as electronic circuits. The new results hold promise for guiding the transmission of light and maintaining the intensity of the signal in very small dimensions.


In bulk MoS2, electrons and photons interact as they would in traditional semiconductors like silicon and gallium arsenide. But when MoS2 is trimmed down to an atomically thin layer, the transfer of energy between electrons and photons becomes highly efficient.*


Combining electronics and photonics on the same integrated circuits could drastically improve the performance and efficiency of mobile technology. The researchers say the next step is to create a near-field detector based on MoS2 and an MoS2 light-emitting diode coupled to on-chip nanoplasmonic circuitry.


* The key to MoS2′s desirable photonic properties is in the structure of its energy band gap. As the material’s layer count decreases, it transitions from an indirect to direct band gap, which allows electrons to easily move between energy bands by releasing photons. Graphene is inefficient at light emission because it has no band gap.

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Scientists unveil new nano-sized synthetic scaffolding technique to make peptoid nanosheets

Scientists unveil new nano-sized synthetic scaffolding technique to make peptoid nanosheets | Amazing Science | Scoop.it

Scientists, including University of Oregon chemist Geraldine Richmond, have tapped oil and water to create scaffolds of self-assembling, synthetic proteins called peptoid nanosheets that mimic complex biological mechanisms and processes.

The accomplishment — detailed this week in apaper placed online ahead of print by the Proceedings of the National Academy of Sciences — is expected to fuel an alternative design of the two-dimensional peptoid nanosheets that can be used in a broad range of applications. Among them could be improved chemical sensors and separators, and safer, more effective drug-delivery vehicles.

Study co-author Ronald Zuckermann of the Molecular Foundry at Lawrence Berkeley National Laboratory (LBNL) first developed these ultra-thin nanosheets in 2010 using an air-and-water combination.

"We often think of oil on water as something that is environmentally bad when, in fact, my group over the past 20 years has been studying the unique properties of the junction between water and oil as an interesting place for molecules to assemble in unique ways — including for soaps and oil dispersants," said Richmond, who holds a UO presidential chair. "This study shows it is also a unique platform for making nanosheets."

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RNA origami is a new method for self-organizing molecules on nanoscale

RNA origami is a new method for self-organizing molecules on nanoscale | Amazing Science | Scoop.it

Using just a single strand of RNA, many complicated shapes can be fabricated by RNA origami. Unlike existing methods for folding DNA molecules, RNA origamis are produced by enzymes and they simultaneously fold into pre-designed shapes. These features may allow designer RNA structures to be grown within living cells and used to organize cellular enzymes into biochemical factories. The method, which was developed by researchers from Aarhus University (Denmark) and California Institute of Technology, is reported in the latest issue of Science.


Origami, the Japanese art of paper folding, derives its elegance and beauty from the manipulation of a single piece of paper to make a complex shape. The RNA origami method described in the new study likewise involves the folding of a single strand of RNA, but instead of the experimenters doing the folding, the molecules fold up on their own.


"What is unique about the method is that the folding recipe is encoded into the molecule itself, through its sequence." explains Cody Geary, a postdoctoral scholar in the field of RNA structure and design at Aarhus University. "The sequence of the RNAs defines both the final shape and also the series of movements that rearrange the structures as they fold."


"The challenge of designing RNAs that fold up on their own is particularly difficult, since the molecules can easily get tangled during the folding process. So to design them, you really have to imagine the way that the molecules must twist and bend to obtain their final shape." Geary says.


The researchers used 3D models and computer software to design each RNA origami, which was then encoded as a synthetic DNA gene. Once the DNA gene was produced, simply adding the enzyme RNA-polymerase resulted in the automatic formation of RNA origami.


To observe the RNA molecules the researchers used an atomic force microscope, a type of scanning microscope that softly touches molecules instead of looking at them directly. The microscope is able to zoom in a thousand times smaller than is possible with a conventional light microscope. The researchers have demonstrated their method by folding RNA structures that form honeycomb shapes, but many other shapes should be realizable.


"We designed the RNA molecules to fold into honeycomb patterns because they are easy to recognize in the microscope. In one experiment we caught the polymerases in the process of making the RNAs that assemble into honeycombs, and they really look like honey bees in action." Geary continues.


A method for making origami shapes out of DNA has been around for almost a decade, and has since created many applications for molecular scaffolds. However, RNA has some important advantages over its chemical cousin DNA that make it an attractive alternative:


Paul Rothemund, a research professor at the California Institute of Technology and the inventor of the DNA origami method, is also an author on the new RNA origami work. "The parts for a DNA origami cannot easily be written into the genome of an organism. RNA origami, on the other hand, can be represented as a DNA gene, which in cells is transcribed into RNA by a protein machine called RNA polymerase." explains Rothemund.


Rothemund further adds, "The payoff is that unlike DNA origami, which are expensive and have to be made outside of cells, RNA origami should be able to be grown cheaply in large quantities, simply by growing bacteria with genes for them. Genes and bacteria cost essentially nothing to share, and so RNA origami will be easily exchanged between scientists."


The research was performed at laboratories at Aarhus University in Denmark, and the California Institute of Technology in Pasadena. Ebbe Andersen, an Assistant Professor at Aarhus University, who works on developing molecular biosensors, lead the development of the project.


"All of the molecules and structures that form inside of living cells are the products of self-assembly, but we still know very little about how self-assembly actually works. By designing and testing self-assembling RNA shapes, we have begun to shed some light on fundamental principles of self-assembly." says Andersen.

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‘Nanodaisies’ deliver a more powerful drug cocktail to cancer cells

‘Nanodaisies’ deliver a more powerful drug cocktail to cancer cells | Amazing Science | Scoop.it

Nanoscale flower-like structures that can introduce a “cocktail” of multiple drugs into cancer cells have been developed by biomedical engineering researchers at North Carolina State University and the University of North Carolina at Chapel Hill.


“We found that this technique was much better than conventional drug-delivery techniques at inhibiting the growth of lung cancer tumors in mice,” says Dr. Zhen Gu, senior author of the paper and an assistant professor in the joint biomedical engineering program.


“And based on in vitro (lab) tests in nine different cell lines, the technique is also promising for use against leukemia, breast, prostate, liver, ovarian and brain cancers.”


To make the “nanodaisies,” the researchers begin with a solution that contains a polymer called polyethylene glycol (PEG). The PEG forms long strands that have much shorter strands branching off to either side. Researchers directly link the anti-cancer drug camptothecin (CPT) onto the shorter strands and introduce the anti-cancer drug doxorubicin (Dox) into the solution.


PEG is hydrophilic, meaning it likes water. CPT and Dox are hydrophobic, meaning they don’t like water. As a result, the CPT and Dox cluster together in the solution, wrapping the PEG around themselves. This results in a daisy-shaped drug cocktail, only 50 nanometers in diameter, which can be injected into a cancer patient.

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