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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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How to synthesize structurally pure carbon nanotubes using molecular seeds

How to synthesize structurally pure carbon nanotubes using molecular seeds | Amazing Science | Scoop.it

By smoothing nanotube irregularities, a new process could lead to smaller, faster-switching next-generation electronic and electro-optical components. Researchers at Empa and the Max Planck Institute for Solid State Research have succeeded in “growing” single-wall carbon nanotubes (SWCNTs) with a single predefined structure, with identical electronic properties.


The CNTs self-assembled out of tailor-made organic precursor molecules on a platinum surface, as reported by the researchers in the journal Nature.


With a diameter of roughly one nanometer, SWCNTs should be considered as quantum structures; the slightest structural changes, such as differences in diameter or in the alignment of the atomic lattice, may result in dramatic changes in electronic properties.


One SWCNT may be metallic, while another one with a slightly different structure is a semiconductor. So there is a great deal of interest in reliable methods of making SWCNTs as structurally uniform as possible. Such CNTs could help create next-generation electronic and electro-optical components that are smaller than ever before, allowing for faster switching times.


Here’s how the researchers did it:


  1. Transform the flat (2D) starting molecule into a three-dimensional object, the “germling.” This takes place on a hot platinum surface using a catalytic reaction in which hydrogen atoms are split off and new carbon-carbon bonds are formed at very specific locations. The “germ” — a small, dome-like entity with an open edge that sits on the platinum surface — is “folded” out of the flat molecule. This “end cap” forms the “lid” of the growing SWCNT.
  2. Attach more carbon atoms, which originate from the catalytic decomposition of ethylene (C2H4) on the platinum surface. They position themselves on the open edge between the platinum surface and the end cap, and raise the cap higher and higher, causing the nanotube to grow slowly upwards.


Only the germ defines the nanotube’s atomic structure, as the researchers were able to demonstrate through the analysis of the vibration modes of the SWCNTs and scanning tunnel microscope (STM) measurements. Further investigations using the new scanning helium ion microscope (SHIM) at Empa show that the resulting SWCNTs reach lengths greater than 300 nanometers.


The SWCNTs synthesized in this study are mirror-image symmetrical entities. However, depending on the manner in which the honeycombed atomic lattice is derived from the starting molecule (“straight” or “oblique” in relation to the CNT axis), it would also possible be possible to produce helically wound nanotubes, i.e., nanotubes twisting to the right or left, which are not mirror-image symmetrical.


This structure also determines the electronic, thermoelectric, and optical properties of the material. So in principle, the researchers could produce materials with different properties in a targeted manner by selecting the starting molecule.


The project was supported by the Swiss National Science Foundation (FNSNF).

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Nanostructured metal-oxide catalyst efficiently converts CO2 to methanol

Nanostructured metal-oxide catalyst efficiently converts CO2 to methanol | Amazing Science | Scoop.it

Scanning tunneling microscope image of a cerium-oxide and copper catalyst (CeOx-Cu) used in the transformation of carbon dioxide (CO2) and hydrogen (H2) gases.


Scientists at Brookhaven National Laboratory have discovered a new catalytic system for converting carbon dioxide (CO2) to methanol — a key commodity used to create a wide range of industrial chemicals and fuels. With significantly higher activity than other catalysts now in use, the new system could make it easier to get normally unreactive CO2 to participate in these reactions.


“Developing an effective catalyst for synthesizing methanol from CO2 could greatly expand the use of this abundant gas as an economical feedstock,” said Brookhaven chemist Jose Rodriguez, who led the research. “It’s even possible to imagine a future in which such catalysts help capture CO2 emitted from methanol-powered combustion engines and fuel cells, and recycling it to synthesize new fuel,” he said.

That future, of course, will be determined by a variety of factors, including economics.


The research team, which included scientists from Brookhaven, the University of Seville in Spain, and Central University of Venezuela, describes their results in the August 1, 2014, issue of the journal Science.


Because CO2 is normally such a reluctant participant in chemical reactions, interacting weakly with most catalysts, it’s also rather difficult to study. The new studies required the use of newly developed in-situ (or on-site, meaning under reaction conditions) imaging and chemical “fingerprinting” techniques.


These techniques allowed the scientists to peer into the dynamic evolution of a variety of catalysts as they operated in real time. The scientists also used computational modeling at the University of Seville and the Barcelona Supercomputing Center to provide a molecular description of the methanol synthesis mechanism.


The team was particularly interested in exploring a catalyst composed of copper and ceria (cerium-oxide) nanoparticles, sometimes also mixed with titania. The scientists’ previous studies with such metal-oxide nanoparticle catalysts have demonstrated their exceptional reactivity in a variety of reactions. In those studies, the interfaces of the two types of nanoparticles turned out to be critical to the reactivity of the catalysts, with highly reactive sites forming at regions where the two phases meet.


To explore the reactivity of such dual particle catalytic systems in converting CO2 to methanol, the scientists used spectroscopic techniques to investigate the interaction of CO2 with plain copper, plain cerium-oxide, and cerium-oxide/copper surfaces at a range of reaction temperatures and pressures. Chemical fingerprinting was combined with computational modeling to reveal the most probable progression of intermediates as the reaction from CO2 to methanol proceeded.


These studies revealed that the metal component of the catalysts alone could not carry out all the chemical steps necessary for the production of methanol. The most effective binding and activation of CO2 occurred at the interfaces between metal and oxide nanoparticles in the cerium-oxide/copper catalytic system.


“The key active sites for the chemical transformations involved atoms from the metal [copper] and oxide [ceria or ceria/titania] phases,” said Jesus Graciani, a chemist from the University of Seville and first author on the paper. The resulting catalyst converts CO2 to methanol more than a thousand times faster than plain copper particles, and almost 90 times faster than a common copper/zinc-oxide catalyst currently in industrial use.

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Eric Chan Wei Chiang's curator insight, August 2, 11:21 PM

The transformation of CO2 into alcohols or other hydrocarbon compounds is challenging because catalysing the formation of carbon-carbon bonds is very difficult. To illustrate, Victor Grignard won the Nobel Prize in 1912 for developing reagents which forms carbon-carbon bonds.


Nonetheless, this technology has vast implications in space exploration and sustainable energy:

http://www.scoop.it/t/world-of-tomorrow/?tag=Space+Exploration

http://www.scoop.it/t/aquascaping-and-nature/?tag=Sustainable+Energy

 

On carbon fixation, an artificial leaf devised using real chloroplast is described here: http://sco.lt/7MI8mX

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Screw-shaped nanopropeller can actively move in a gel-like fluid

Screw-shaped nanopropeller can actively move in a gel-like fluid | Amazing Science | Scoop.it

Schematic of micro- and nanopropellers in hyaluronan gels. The polymeric mesh structure blocks the larger micropropellers (top left), but smaller propellers.


Israeli and German researchers have created a nanoscale screw-shaped propeller that can move in a gel-like fluid, mimicking the environment inside a living organism, as described in a paper published in the June 2014 issue of ACS Nano.


The team comprises researchers from Technion, the Max Planck Institute for Intelligent Systems, and the Institute for Physical Chemistry at the University of Stuttgart.


The filament that makes up the propeller, made of silica and nickel, is only 70 nanometers in diameter; the entire propeller is 400 nanometers long, small enough that their motion can be affected by Brownian motion of nearby molecules.


To test if the propellers could move through living organisms, they used hyaluronan, a material that occurs throughout the human body, including the synovial fluids in joints and the vitreous humor in your eyeball.


The hyaluronan gel contains a mesh of long proteins called polymers; the polymers are large enough to prevent micron-sized (millionths of a meter) propellers from moving much at all. But the openings are large enough for nanometer-sized objects to pass through. The scientists were able to control the motion of the propellers using a relatively weak rotating magnetic field.


“One can now think about targeted applications, for instance, in the eye, where they may be moved to a precise location at the retina,” says Peer Fischer, a member of the research team and head of the Micro, Nano, and Molecular Systems Lab at the Max Planck Institute for Intelligent Systems.


Scientists could also attach “active molecules” to the tips of the propellers, or use the propellers to deliver tiny targeted doses of radiation.

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Technique simplifies the creation of high-tech crystals

Technique simplifies the creation of high-tech crystals | Amazing Science | Scoop.it

Highly purified crystals that split light with uncanny precision are key parts of high-powered lenses, specialized optics and, potentially, computers that manipulate light instead of electricity. But producing these crystals by current techniques, such as etching them with a precise beam of electrons, is often extremely difficult and expensive.


Now, researchers at Princeton and Columbia universities have proposed a new method that could allow scientists to customize and grow these specialized materials, known asphotonic crystals, with relative ease.


"Our results point to a previously unexplored path for making defect-free crystals using inexpensive ingredients," said Athanassios Panagiotopoulos, the Susan Dod Brown Professor of Chemical and Biological Engineering and one of the paper's authors. "Current methods for making such systems rely on using difficult-to-synthesize particles with narrowly tailored directional interactions."


Via Alin Velea
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Designing nanoparticles that can deliver drugs more easily

Designing nanoparticles that can deliver drugs more easily | Amazing Science | Scoop.it

A new study led by MIT materials scientists reveals the reason why gold nanoparticles  can easily slip through cell membranes to deliver drugs directly to target cells. The nanoparticles enter cells by taking advantage of a route normally used in vesicle-vesicle fusion, a crucial process that allows signal transmission between neurons.


In the July 21 issue of Nature Communications, the researchers describe in detail the mechanism by which these nanoparticles are able to fuse with a membrane. The findings suggest possible strategies for designing nanoparticles — made from gold or other materials — that could get into cells even more easily.


“We’ve identified a type of mechanism that might be more prevalent than is currently known,” says Reid Van Lehn, an MIT graduate student in materials science and engineering and one of the paper’s lead authors. “By identifying this pathway for the first time it also suggests not only how to engineer this particular class of nanoparticles, but that this pathway might be active in other systems as well.”


Most nanoparticles enter cells through endocytosis, a process that traps the particles in intracellular compartments, which can damage the cell membrane and cause cell contents to leak out. But in 2008, MIT researchers found that a special class of gold nanoparticles coated with a mix of molecules could enter cells without any disruption.


Last year, they discovered that the particles were somehow fusing with cell membranes and being absorbed into the cells. In their new study, they created detailed atomistic simulations to model how this happens, and performed experiments that confirmed the model’s predictions.


References:

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Powerful new sensor identfies molecules containing fewer than 20 atoms

Powerful new sensor identfies molecules containing fewer than 20 atoms | Amazing Science | Scoop.it

Researchers at Rice University’s Laboratory for Nanophotonics (LANP) have created a unique sensor that amplifies the optical signature of molecules by about 100 billion times — accurately identifying the composition and structure of individual molecules containing fewer than 20 atoms.


The new single-molecule imaging method, described  in the journal Nature Communications, uses a form of Raman spectroscopy in combination with optical amplifier, making the sensor about 10 times more powerful that previously reported devices, said LANP Director Naomi Halas, the lead scientist on the study.


“The ideal single-molecule sensor would be able to identify an unknown molecule — even a very small one — without any prior information about that molecule’s structure or composition. That’s not possible with current technology, but this new technique has that potential.”


The optical sensor uses Raman spectroscopy, a technique pioneered in the 1930s that blossomed after the advent of lasers in the 1960s. When light strikes a molecule, most of its photons bounce off or pass directly through, but a tiny fraction — fewer than one in a trillion — are absorbed and re-emitted into another energy level that differs from their initial level. By measuring and analyzing these re-emitted photons through Raman spectroscopy, scientists can decipher the types of atoms in a molecule as well as their structural arrangement.


Scientists have created a number of techniques to boost Raman signals. In the new study, LANP graduate student Yu Zhang used one of these, a two-coherent-laser technique called “coherent anti-Stokes Raman spectroscopy,” or CARS. By using CARS in conjunction with a light amplifier made of four tiny gold nanodiscs, Halas and Zhang were able to measure single molecules in a powerful new way. LANP has dubbed the new technique “surface-enhanced CARS,” or SECARS.

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Blackest is the new black: Scientists have developed a material so dark that you can't see it

Blackest is the new black: Scientists have developed a material so dark that you can't see it | Amazing Science | Scoop.it

A British company has produced a "strange, alien" material so black that it absorbs all but 0.035 per cent of visual light, setting a new world record. To stare at the "super black" coating made of carbon nanotubes – each 10,000 times thinner than a human hair – is an odd experience. It is so dark that the human eye cannot understand what it is seeing. Shapes and contours are lost, leaving nothing but an apparent abyss.


If it was used to make one of Chanel's little black dresses, the wearer's head and limbs might appear to float incorporeally around a dress-shaped hole.


Actual applications are more serious, enabling astronomical cameras, telescopes and infrared scanning systems to function more effectively. Then there are the military uses that the material's maker, Surrey NanoSystems, is not allowed to discuss.


The nanotube material, named Vantablack, has been grown on sheets of aluminium foil by the Newhaven-based company. While the sheets may be crumpled into miniature hills and valleys, this landscape disappears on areas covered by it.


"You expect to see the hills and all you can see … it's like black, like a hole, like there's nothing there. It just looks so strange," said Ben Jensen, the firm's chief technical officer. Asked about the prospect of a little black dress, he said it would be "very expensive" – the cost of the material is one of the things he was unable to reveal. "You would lose all features of the dress. It would just be something black passing through," he said.


Vantablack, which was described in the journal Optics Express and will be launched at the Farnborough International Airshow this week, works by packing together a field of nanotubes, like incredibly thin drinking straws. These are so tiny that light particles cannot get into them, although they can pass into the gaps between. Once there, however, all but a tiny remnant of the light bounces around until it is absorbed.


Vantablack's practical uses include calibrating cameras used to take photographs of the oldest objects in the universe. This has to be done by pointing the camera at something as black as possible.

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Nanoscribe claims world’s fastest commercially available nano-3D printer title

Nanoscribe claims world’s fastest commercially available nano-3D printer title | Amazing Science | Scoop.it
Nanoscribe GmbH, a spin-off of Karlsruhe Institute of Technology (KIT), has built the world’s fastest 3D printer of micro- and nanostructures.


At the Photonics West, the leading international fair for photonics taking place in San Francisco (USA) this week, Nanoscribe GmbH, a spin-off of Karlsruhe Institute of Technology (KIT), presents the world’s fastest 3D printer of micro- and nanostructures. With this printer, smallest three-dimensional objects, often smaller than the diameter of a human hair, can be manufactured with minimum time consumption and maximum resolution. The printer is based on a novel laser lithography method.

 

“The success of Nanoscribe is an example of KIT’s excellent entrepreneurial culture and confirms our strategy of specifically supporting spin-offs. In this way, research results are transferred rapidly and sustainably to the market,” says Dr. Peter Fritz, KIT Vice President for Research and Innovation. In early 2008, Nanoscribe was founded as the first spin-off of KIT and has since established itself as the world’s market and technology leader in the area of 3D laser lithography.

 

Last year, 18 spin-offs were established at KIT. The 3D laser litho-graphy systems developed by Nanoscribe – the spin-off can still be found on KIT’s Campus North - are used for research by KIT and scientists worldwide. Work in the area of photonics concentrates on replacing conventional electronics by optical circuits of higher performance. For this purpose, Nanoscribe systems are used to print polymer waveguides reaching data transfer rates of more than 5 terabits per second.

 

Biosciences produce tailored scaffolds for cell growth studies among others. In materials research, functional materials of enhanced performance are developed for lightweight construction to reduce the consumption of resources. Among the customers are universities and research institutions as well as industrial companies.

 

Increased Speed: Hours Turn into Minutes


By means of the new laser lithography method, printing speed is increased by factor of about 100. This increase in speed results from the use of a galvo mirror system, a technology that is also applied in laser show devices or scanning units of CD and DVD drives. Reflecting a laser beam off the rotating galvo mirrors facilitates rapid and precise laser focus positioning. “We are revolutionizing 3D printing on the micrometer scale. Precision and speed are achieved by the industrially established galvo technology. Our product benefits from more than one decade of experience in photonics, the key technology of the 21st century,” says Martin Hermatschweiler, the managing director of Nanoscribe GmbH.

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Sperm-inspired microrobots controlled by magnetic fields

Sperm-inspired microrobots controlled by magnetic fields | Amazing Science | Scoop.it

MagnetoSperm performs a flagellated swim using weak oscillating magnetic fields.


A team of researchers at the University of Twente (Netherlands) and German University in Cairo has developed sperm-inspired microrobots that can be controlled by weak oscillating magnetic fields.


Described in a cover article in AIP Publishing’s journal Applied Physics Letters, the 322 micron-long robots consist of a head coated in a thick cobalt-nickel layer and an uncoated tail.


When the microrobot is subjected to an oscillating field of less than five millitesla — about the strength of a decorative refrigerator magnet — it experiences a magnetic torque on its head, which causes its flagellum to oscillate and propel it forward.


The researchers are then able to steer the robot by directing the magnetic field lines towards a reference point. The propulsion mechanism allows for swimming at an average speed of about 158 microns/second with a weak 45 Hz magnetic field.


Islam Khalil, PhD, an Assistant Professor of the German University in Cairo, designed the MagnetoSperm microrobots along with Sarthak Misra, PhD, and colleagues at MIRA-Institute for Biomedical Technology and Technical Medicine at the University of Twente.


“Nature has designed efficient tools for locomotion at micro-scales. Our microrobots are either inspired from nature or directly use living micro-organisms such as magnetotactic bacteria and sperm cells for complex micro-manipulation and targeted therapy tasks,” said Misra, the principal investigator of this study, and an associate professor at the University of Twente.

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A simple, inexpensive supersonic spray method creates high-quality graphene layers

A simple, inexpensive supersonic spray method creates high-quality graphene layers | Amazing Science | Scoop.it

A simple, inexpensive spray method that deposits a graphene film can heal manufacturing defects and produce a high quality graphene layer on a range of substrates, report researchers at the University of Illinois at Chicago and Korea University — an alternative to the chemical vapor deposition process developed by MIT and the University of Michigan for creating large sheets of graphene, recently reported.


Graphene, a two-dimensional wonder-material composed of a single layer of carbon atoms, is strong, transparent, and an excellent conductor of electricity. It has potential in a wide range of applications, such as reinforcing and lending electrical properties to plastics; creating denser and faster integrated circuits; and building better touch screens.


However, there has been no easy way to scale up from microscopic to large-scale applications without introducing defects, says Alexander Yarin, UIC professor of mechanical and industrial engineering and co-principal investigator on the study.


“Yarin first turned to solving how to deposit graphene flakes to form a consistent layer without any clumps or spaces. He went to Sam S. Yoon, professor of mechanical engineering at Korea University and co-principal investigator on the study.


Yoon had been working with a unique kinetic spray deposition system that exploits the supersonic acceleration of droplets through a Laval nozzle. Although Yoon was working with different materials, Yarin believed his method might be used to deposit graphene flakes into a smooth layer.

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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.


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Nanoparticles open a new window into the brain

Nanoparticles open a new window into the brain | Amazing Science | Scoop.it

New imaging technique could help treat strokes, cancer and dementia.


Researchers at Stanford University in the US have developed the first non-invasive imaging technique that can detect micron-sized structures within blood vessels in the brains of mice. The method involves detecting near-infrared fluorescent light from single-walled carbon nanotubes (SWCNTs) that are injected into the mice. The ability to monitor the structure of blood vessels – and the blood flow within them – is extremely important for treating conditions such as strokes, dementia and brain tumors.


Today, brain imaging mainly relies on techniques such as X-ray computed tomography and magnetic resonance angiography. However, these methods cannot image structures several microns in size. In addition, with these approaches it can take several minutes to acquire an image, which means that it is not possible to use them to monitor blood flow in real time.


Fluorescence-based brain imaging in the visible and near-infrared (NIR) regions of the electromagnetic spectrum (400–900 nm) is a good alternative but at the moment it requires skull-thinning or, worse still, craniotomy – where sections of the skull are removed and replaced with a transparent "window" – to work properly. This is because light at these wavelengths can only travel about 1 mm through the skull.


Now, a team led by Hongjie Dai and Calvin Kuo at Stanford has developed a new through-scalp and through-skull fluorescence imaging technique that goes a long way in overcoming these problems. The method makes use of the intrinsic fluorescence of SWCNTs in the 1.3–1.4 µm range. "We define this wavelength as the NIR-IIa window, and it represents just about the longest wavelengths for fluorescence imaging reported thus far," explains Dai.


"Photons at these wavelengths are much less scattered than those in the 400–900 nm window when traversing biological tissues and are not absorbed significantly by water either," says Dai. "All in all, this allows us to see deeper into the brain through intact scalp skin and bone than is possible with traditional fluorescence imaging, which is mostly done with <800 nm wavelength photons."


"Compared with all other techniques for in vivo brain imaging (including MRI and CT), our technique affords higher spatial resolution", he says. "It allows us to image single capillary blood vessels that are just microns across and as deep as 3 mm inside the brain."

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A new way to make microstructured surfaces

A new way to make microstructured surfaces | Amazing Science | Scoop.it

A team of researchers has created a new way of manufacturing microstructured surfaces that have novel three-dimensional textures. These surfaces, made by self-assembly of carbon nanotubes, could exhibit a variety of useful properties — including controllable mechanical stiffness and strength, or the ability to repel water in a certain direction.


“We have demonstrated that mechanical forces can be used to direct nanostructures to form complex three-dimensional microstructures, and that we can independently control … the mechanical properties of the microstructures,” says A. John Hart, the Mitsui Career Development Associate Professor of Mechanical Engineering at MIT and senior author of a paper describing the new technique in the journal Nature Communications.


The technique works by inducing carbon nanotubes to bend as they grow. The mechanism is analogous to the bending of a bimetallic strip, used as the control in old thermostats, as it warms: One material expands faster than another bonded to it.  But in this new process, the material bends as it is produced by a chemical reaction. 


The process begins by printing two patterns onto a substrate: One is a catalyst of carbon nanotubes; the second material modifies the growth rate of the nanotubes. By offsetting the two patterns, the researchers showed that the nanotubes bend into predictable shapes as they extend.


“We can specify these simple two-dimensional instructions, and cause the nanotubes to form complex shapes in three dimensions,” says Hart. Where nanotubes growing at different rates are adjacent, “they push and pull on each other,” producing more complex forms, Hart explains. “It’s a new principle of using mechanics to control the growth of a nanostructured material,” he says.


Few high-throughput manufacturing processes can achieve such flexibility in creating three-dimensional structures, Hart says. This technique, he adds, is attractive because it can be used to create large expanses of the structures simultaneously; the shape of each structure can be specified by designing the starting pattern. Hart says the technique could also enable control of other properties, such as electrical and thermal conductivity and chemical reactivity, by attaching various coatings to the carbon nanotubes after they grow.


“If you coat the structures after the growth process, you can exquisitely modify their properties,” says Hart. For example, coating the nanotubes with ceramic, using a method called atomic layer deposition, allows the mechanical properties of the structures to be controlled. “When a thick coating is deposited, we have a surface with exceptional stiffness, strength, and toughness relative to [its] density,” Hart explains. “When a thin coating is deposited, the structures are very flexible and resilient.”


This approach may also enable “high-fidelity replication of the intricate structures found on the skins of certain plants and animals,” Hart says, and could make it possible to mass-produce surfaces with specialized characteristics, such as the water-repellent and adhesive ability of some insects. “We’re interested in controlling these fundamental properties using scalable manufacturing techniques,” Hart says.  

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Scientists develop a 'nanovesicle' that delivers complementary molecules inside cells

Scientists develop a 'nanovesicle' that delivers complementary molecules inside cells | Amazing Science | Scoop.it

Researchers at the University of Miami and the University of Ulster have created self-assembling nanoparticles that can transport drugs and other molecules into target living cells.


The new nanocarriers are just 15 nanometers in diameter, based on building blocks called amphiphilic polymers: they have both hydrophilic (water-loving, polar) and lipophilic (fat-loving) properties). That allows the nanocarriers to hold the guest molecules within their water-insoluble interior and use their water-soluble exterior to travel through an aqueous environment. And that makes the nanocarriers ideal for transferring molecules that would otherwise be insoluble in water.


They also emit a fluorescent signal that can be observed with a microscope, allowing for tracking and photographing the nanoparticles in the body.


“The size of these nanoparticles, their dynamic character and the fact that the reactions take place under normal biological conditions (at ambient temperature and neutral environment) makes these nanoparticles an ideal vehicle for the controlled activation of therapeutics, directly inside the cells,” says lead investigator Francisco Raymo, professor of chemistry in the University of Miami College of Arts and Sciences and UM laboratory for molecular photonics.


The next phase of this investigation involves demonstrating that this method can be used to achieve chemical reactions inside cells, instead of energy transfers.

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The Motion of the Medium Matters for Self-assembling Particles

The Motion of the Medium Matters for Self-assembling Particles | Amazing Science | Scoop.it

By attaching short sequences of single-stranded DNA to nanoscale building blocks, researchers can design structures that can effectively build themselves. The building blocks that are meant to connect have complementary DNA sequences on their surfaces, ensuring only the correct pieces bind together as they jostle into one another while suspended in a test tube.


Now, a University of Pennsylvania team has made a discovery with implications for all such self-assembled structures.


Earlier work assumed that the liquid medium in which these DNA-coated pieces float could be treated as a placid vacuum, but the Penn team has shown that fluid dynamics play a crucial role in the kind and quality of the structures that can be made in this way.


As the DNA-coated pieces rearrange themselves and bind, they create slipstreams into which other pieces can flow. This phenomenon makes some patterns within the structures more likely to form than others.


The research was conducted by professors Talid Sinno and John Crocker, alongside graduate students Ian Jenkins, Marie Casey and James McGinley, all of the Department of Chemical and Biomolecular Engineering in Penn’s School of Engineering and Applied Science.


It was published in the Proceedings of the National Academy of Sciences.

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Ultrasound waves can spin a 200 nm wide gold nanomotor rod up to an impressive rotation of 150,000 rpm

Ultrasound waves can spin a 200 nm wide gold nanomotor rod up to an impressive rotation of 150,000 rpm | Amazing Science | Scoop.it

Scientists at the National Institute of Standards and Technology (NIST) have discovered that a gold nanorod submerged in water and exposed to high-frequency ultrasound waves can spin at an incredible speed of 150,000 RPM, about ten times faster than the previous record. The advance could lead to powerful nanomotors with important applications in medicine, high-speed machining, and the mixing of materials.


Take a rod only a few nanometers in size and find a way to make it spin as fast as possible, for as long as possible, and controlling it as precisely as possible. What you get is a nanomotor, a device that could one day be used to power hordes of tiny robots to build complex nanostructured materials or deliver drugs directly from inside a living cell.


Nanomotors have made giant strides in recent years: they've gotten much smaller and more reliable, and we can now also power them in many different ways. Available options include electricity, magnetic fields, blasting them with photons and, more recently, using ultrasound to rotate rods while they're submerged in water, which could prove very useful in a biological environment.


Previous studies have shown that applying a combination of ultrasound and magnetic fields can control both the spin and the forward motion of the nanorods, but nobody could tell just how fast they were spinning. Now, researchers at NIST have found that, despite being submerged in water, the rods are spinning at an impressive 150,000 RMP, which is 10 times faster than any nanoscale object submerged in liquid ever reported.


To clock the motor's speed, the researchers used gold rods which were 2 micrometers long and 300 nanometer wide. The rods were submerged in water and mixed with polystyrene nanoparticles, and positioned just above a speaker-type shaker.

The researchers will now focus on understanding exactly why the motors rotate (which is not yet well understood) and how the vortexes around the rods affects their interactions with each other.


A paper published in the journal ACS Nano describes the advance.

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Morphing material could allow robots to switch between hard and soft states

Morphing material could allow robots to switch between hard and soft states | Amazing Science | Scoop.it

A new Terminator T-1000 robot-style material made of wax and foam — and capable of switching between hard and soft states — could be used to build morphing surgical robots that move through the body to reach a desired location without damaging organs or vessels along the way.


Robots built from the material, described in a new paper in the journal Macromolecular Materials and Engineering, could also be used in search-and-rescue operations to squeeze through rubble looking for survivors, says Anette Hosoi, an MIT professor of mechanical engineering and applied mathematics who led the research team.


MIT is working on the project with robotics company Boston Dynamics, who began developing the material as part of DARPA’s Chemical Robots program, the Max Planck Institute for Dynamics and Self-Organization, and Stony Brook University.


Controlling a very soft structure is difficult, compared to a rigid robot. It’s much harder to predict how the material will move and what shapes it will form. So the researchers decided to develop a material that can switch between a soft and hard state by coating a foam structure in wax. Foam can be squeezed into a small fraction of its normal size, but once released will bounce back to its original shape.


The wax coating, meanwhile, can change from a hard outer shell to a soft, pliable surface with moderate heating. This could be done by running a wire along each of the coated foam struts and then applying a current to heat up and melt the surrounding wax. Turning off the current again would allow the material to cool down and return to its rigid state.

In addition to switching the material to its soft state, heating the wax in this way would also repair any damage sustained, Hosoi says. “This material is self-healing,” she says. “So if you push it too far and fracture the coating, you can heat it and then cool it, and the structure returns to its original configuration.”


To build the material, the researchers simply placed the polyurethane foam in a bath of melted wax. They also found that a 3D-printed lattice worked better than the polyurethane foam, which would still be fine for low-cost applications, Hosoi says. The wax coating could also be replaced by a stronger material, such as solder, she adds.


Hosoi is now investigating the use of other unconventional materials for robotics, such as magnetorheological and electrorheological fluids. These materials consist of a liquid with particles suspended inside, and can be made to switch from a soft to a rigid state with the application of a magnetic or electric field.


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Million-fold smaller "nano-pixels" hold huge potential for flexible, low-power, high-res screens

Million-fold smaller "nano-pixels" hold huge potential for flexible, low-power, high-res screens | Amazing Science | Scoop.it

The Retina displays featured on Apple's iPhone 4 and 5 models pack a pixel density of 326 ppi, with individual pixels measuring 78 micrometers. That might seem plenty good enough given the average human eye is unable to differentiate between the individual pixels, but scientists in the UK have now developed technology that could lead to extremely high-resolution displays that put such pixel densities to shame.


Led by Oxford University scientists, a research team has created a prototype device that features pixels just 30 x 30 nanometers in size. The high resolution potential of the technology was discovered while the team was exploring the link between the electrical and optical properties of phase change materials (PCMs) that can switch from an amorphous to a crystalline state.


By sandwiching a seven-nanometer thick layer of the PCM Germanium-Antimony-Tellurium (Ge2Sb2Te5 or GST) between two layers of transparent electrodes made of indium tin oxide (ITO), the scientists discovered they could "draw" still images within the sandwich "stack" using an atomic force microscope. They then found that the "nano-pixels" could be switched on and off electronically, creating colored dots that could be used as the basis for an extremely high-resolution display.


"We didn't set out to invent a new kind of display," said Professor Harish Bhaskaran of Oxford University's Department of Materials, who led the research. "We were exploring the relationship between the electrical and optical properties of phase change materials and then had the idea of creating this GST 'sandwich' made up of layers just a few nanometers thick. We found that not only were we able to create images in the stack but, to our surprise, thinner layers of GST actually gave us better contrast. We also discovered that altering the size of the bottom electrode layer enabled us to change the color of the image."


But extremely high-resolution isn't the only impressive quality of the technology. The layers that make up the GST sandwich are created using a sputtering technique, which would allow them to be deposited as thin films on extremely thin and flexible substrates.


"We have already demonstrated that the technique works on flexible Mylar sheets around 200 nanometres thick," said Professor Bhaskaran. "This makes them potentially useful for 'smart' glasses, foldable screens, windshield displays, and even synthetic retinas that mimic the abilities of photoreceptor cells in the human eye."

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Design of self-assembling protein nanomachines: A nanocage builds itself from engineered components

Design of self-assembling protein nanomachines: A nanocage builds itself from engineered components | Amazing Science | Scoop.it
Biological systems produce an incredible array of self-assembling protein tools on a nanoscale, such as molecular motors, delivery capsules and injection devices. Inspired by sophisticated molecular machines naturally found in living things, scientists want to build their own with forms and functions customized to tackle modern day challenges. A new computational method, proven to accurately design protein nanomaterials that arrange themselves into a symmetrical, cage-like structure, may be an important step toward that goal.
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Gold Nanoparticles and Near-infrared Light Kill Cancer Cells With Heat

Gold Nanoparticles and Near-infrared Light Kill Cancer Cells With Heat | Amazing Science | Scoop.it

Researchers devise a way to make gold nanoparticles absorb light cheaply and effectively.


Nanoparticles have been suggested as a way to kill cancer cells in a multitude of ways. Recent research has suggested a method for surrounding gold nanoparticles with nanobubbles that would rip open small pores in cancer cell membranes. This would allow drugs present outside the cells to get in. Another cancer killing treatment is tricking lymphoma cells into eating gold nanoparticles. Once ingested, the nanoparticles make it impossible for the cancer cells to eat anything else, dooming them to death by starvation.


You may have noticed the recurring use of gold nanoparticles in cancer research. Following that tradition, researchers at ETH Zurich in Switzerland have demonstrated that gold nanoparticles, in combination with near-infrared light, can turn up the heat on cancer cells enough to kill tumors.


While gold nanoparticles are well tolerated by the human body, they are not too good at absorbing long-wavelength red light, which is able to penetrate human tissue better than short-wavelength blue light. The nanoparticles that are effective at this are known as plasmonic nanoparticles. Plasmonics is a field in which free electrons in a metal can be excited by the electric component of light so that there are collective oscillations in the material with heat generation being one effect.


The ETH Zurich researchers knew that if they molded the gold nanoparticles into a particular shape, such as a rod or a shell, they could give it the plasmonic property for absorbing near-infrared light it otherwise lacked. The problem with this approach is that is complex and expensive.


In research published the journal Advanced Functional Materials ("Photothermal Killing of Cancer Cells by the Controlled Plasmonic Coupling of Silica-Coated Au/Fe2O3 Nanoaggregates"), the Swiss researchers devised a way to make sphere-shaped gold nanoparticles aggregate into a light-absorbing design. To do this, each particle was coated with a silicon dioxide layer that serves as a buffer between the individual spheres in the aggregate. Maintaining precise spacing between each nanoparticle makes the configuration absorb the near-infrared light.

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