#Single unlabelled biomolecules can be detected through light Being able to track individual biomolecules and observe them at work is every biochemist's dream.
This would enable the scientists to research in detail and better understand the workings of the nanomachines of life, such as ribosomes and DNA polymerases.
Researchers at the Max Planck Institute for the Science of Light have taken a big step closer to this goal.
Using an optical microstructure and gold nanoparticles, they have amplified the interaction of light with DNA to the extent that they can now track interactions between individual DNA molecule segments.
Their optical biosensor for single unlabelled molecules could also be a breakthrough in the development of biochips:
fingernail-size mini-labs in mobile analytical devices could test a drop of blood for multiple diseases simultaneously
Our understanding of fundamental life processes was made first possible by knowledge of how individual biomolecules interact with each other.
In cells, nanomachines such as ribosomes and DNA polymerases stitch individual molecules together to form complex biological structures such as proteins and DNA molecules, the repositories of genetic information.
and it can interfere with the function of the biological nanomachines. Although light can be used to detect unlabelled biomolecules,
the approach cannot be used to detect single DNA molecules, as the interaction of light waves with the molecule is too weak.
and gold nanowires approx. 12 nanometres in diameter and 42 nanometres in length. The gold wire is therefore only about one ten-thousandth the thickness of a hair.
The microsphere and nanowire amplify the interaction between light and molecules. With the help of a prism, the researchers shine laser light into the microsphere.
similar to the way sound waves travel along the walls of a circular enclosure or whispering gallery: when someone whispers at one end of the domed or vaulted gallery,
Vollmer and his colleagues therefore fix a nanowire to the surface of the glass bead.
The light whizzing past generates plasmons: collective oscillations of electrons.""The plasmons pull the light wave a little further out of the glass microsphere,
"Vollmer explains. This amplifies the field strength of the light wave by a factor of more than a thousand.
The gain in signal is then sufficient to detect single biomolecules, such as DNA fragments. The Erlangen-based researchers did precisely that.
to the nanowire mounted on the microsphere. When a matching, i e. COMPLEMENTARY DNA fragment binds to the"bait"on the nanowire
the wavelength of the light shifts and is amplified by the microsphere and nanowire. This shift can be measured.
Different strand sections can be distinguished by their binding behaviour However, the physicists used a shorter DNA fragment than is usual in similar procedures.
Like a short piece of tape on a wall, short DNA fragments do not adhere strongly to each other,
Even in nature, the bonds formed between molecules and nanomachines are fleeting. Thanks to the new method, it is now possible to explore such natural kinetics in greater detail,
says Frank Vollmer.""More research is needed, "says the physicist, who is looking forward to tackling future challenges.
The scientists would also like to integrate their photonic biodetector into optical microchips for use in clinical diagnostics s
#Engineers show light can play seesaw at the nanoscale University of Minnesota electrical engineering researchers have developed a unique nanoscale device that for the first time demonstrates mechanical transportation of light.
The discovery could have major implications for creating faster and more efficient optical devices for computation and communication.
The research paper by University of Minnesota electrical and computer engineering assistant professor Mo Li and his graduate student Huan Li has been published online
and will appear in the October issue of Nature Nanotechnology researchers developed a novel nanoscale device that can capture measure
The tiny device is just. 7 micrometers by 50 micrometer (about. 00007 by. 005 centimeters) and works almost like a seesaw.
which corresponds to about one-third of a thousand-trillionth of a pound or one-seventh of a thousand-trillionth of a kilogram.
Professor Li and his research team also used the seesaw to experimentally demonstrate for the first time the mechanical control of transporting light.
and leave the cavity on the right side empty the force generated by the photons started to oscillate the seesaw.
For comparison a 10w light bulb emits 1020 photons every second. The team's ultimate goal is to transport only one photon in a cycle
The ability to mechanically control photon movement as opposed to controlling them with expensive and cumbersome optoelectronic devices could represent a significant advance in technology said Huan Li the lead author of the paper.
The research could be used to develop an extremely sensitive micromechanical way to measure acceleration of a car
They expect that such devices could play a role in developing microelectronic circuits that would use light instead of electrons to carry data
and consume less power than traditional integrated circuits. Explore further: Breakthrough in light sources for new quantum technology More information:
Optomechanical photon shuttling between photonic cavities Nature Nanotechnology (2014) DOI: 10.1038/nnano. 2014.20 0
#A nanosized hydrogen generator (Phys. org) esearchers at the US Department of energy's (DOE) Argonne National Laboratory have created a small scale"hydrogen generator"that uses light
but also carbon dioxide greenhouse gas byproduct which escapes into the atmosphere. Argonne's early-stage generator, composed of many tiny assemblies,
Scaling this research up in the future may mean that you could replace the gas in your cars and generators with hydrogen greener option,
"Many researchers are looking to inorganic materials for new sources of energy, "said Elena Rozhkova, chemist at Argonne's Center for Nanoscale Materials, a DOE Office of Science (Office of Basic energy Sciences) User Facility."
"Our goal is to learn from the natural world and use its materials as building blocks for innovation."
"For Rozhkova, this particular building block is inspired by the function of an ancient protein known to turn light into energy.
Researchers have known long that some single-celled organisms use a protein called bacteriorhodopsin (br) to absorb sunlight
and pump protons through a membrane, creating a form of chemical energy. They also know that water can be split into oxygen
and hydrogen by combining these proteins with titanium dioxide and platinum and then exposing them to ultraviolet light.
titanium dioxide only reacts in the presence of ultraviolet light, which makes up a mere four percent of the total solar spectrum.
The researchers also needed a platform on which biological components, like br, could survive and connect with the titanium dioxide catalyst:
in short, a material like graphene. Graphene is a super strong, super light, near totally transparent sheet of carbon atoms and one of the best conductors of electricity ever discovered.
Graphene owes its amazing properties to being two-dimensional.""Graphene not only has all these amazing properties,
"Rozhkova's mini-hydrogen generator works like this: both the br protein and the graphene platform absorb visible light.
Electrons from this reaction are transmitted to the titanium dioxide on which these two materials are anchored, making the titanium dioxide sensitive to visible light.
Simultaneously, light from the green end of the solar spectrum triggers the br protein to begin pumping protons along its membrane.
These protons make their way to the platinum nanoparticles which sit on top of the titanium dioxide. Hydrogen is produced by the interaction of the protons
and electrons as they converge on the platinum. Examinations using a technique called Electron Paramagnetic Resonance (EPR)
and time-resolved spectroscopy at the Center for Nanoscale Materials verified the movements of the electrons within the system,
while electrochemical studies confirmed the protons were transferred. Tests also revealed a new quirk of graphene behavior."
"Rozhkova's hydrogen generator proves that nanotechnology, merged with biology, can create new sources of clean energy.
Her team's discovery may provide future consumers a biologically-inspired alternative to gasoline.""These are the types of discoveries we can make at Argonne,
"said Rozhkova.""Working in the basic energy sciences, we were able to demonstrate an energy-rich biologically-inspired alternative to gas."
"This research,"Photoinduced Electron Transfer pathways in Hydrogen-Evolving Reduced graphene oxide-Boosted Hybrid Nano-Bio Catalyst,
"appeared in the July 7 issue of ACS Nano C
#Graphene sensor tracks down cancer biomarkers 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.
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.
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.
When 8-OHDG attached to the bioreceptor molecules on the sensor there was a notable difference in the graphene channel resistance
and monitor a whole range of diseases as it is quite simple to substitute the specific receptor molecules on the graphene surface.
Now that we've created the first proof-of-concept biosensor using epitaxial graphene we will look to investigate a range of different biomarkers associated with different diseases and conditions as well as detecting a number of different biomarkers on the same chip.
Generic epitaxial graphene biosensors of ultrasensitive detection of cancer risk biomarker Z Tehrani et al 2014 2d Mater. 1 025004. iopscience. iop. org/2053
and supercapacitors An official of a materials technology and manufacturing startup based on a Purdue University innovation says his company is addressing the challenge of scaling graphene production for commercial applications.
Our graphene electrodes are created using a roll-to-roll chemical vapor deposition process and then they are combined with other materials utilizing a different roll-to-roll process he said.
We can give the same foundational graphene electrodes entirely different properties utilizing standard or custom materials that we are developing for our own commercial products.
In essence what we've done is developed scalable graphene electrodes that are foundational pieces and can be customized easily to unique customer applications.
He also is the James G. Dwyer Professor of Mechanical engineering at Purdue. The patented technology has been licensed exclusively to Bluevine Graphene Industries through the Purdue Office of Technology Commercialization.
and in particular our graphene petal technology called Folium#at production scales that provide tremendous pricing advantages.
biosensors and supercapacitors. Johnson said the company's first-generation glucose monitoring technology could impact the use of traditional testing systems like lancets
which are made with gold and other precious metals. The second-generation technology could allow people to use noninvasive methods to test their glucose levels through saliva tears or urine.
Patient noncompliance with doctor-recommended glucose testing frequency can be a problem. By making lancets more affordable and potentially noninvasive we are addressing a critical global need he said.
More frequent tests could lead to better control of the disease which could lead to an associated reduction in health risks.
Supercapacitors are Bluevine Graphene Industries'second application under development for its Folium graphene. Johnson said the company's graphene supercapacitors are reaching the energy density of lithium-ion batteries without a similar energy fade over time.
Our graphene-based supercapacitors charge in just a fraction of the time needed to charge lithium-ion batteries.
There are many consumer industrial and military applications he said. Wouldn't it be great if mobile phones could be recharged fully in only a matter of minutes
and if they kept working like new year after year? Johnson said the company will refine its production
and quality assurance processes to produce commercial volumes of the Folium graphene. We also are focused on working with potential customers to continue to develop baseline products for both our biosensor
and supercapacitor applications he said. Explore further: Graphene reinvents the futur t
#Nanoribbon film keeps glass ice-free: Team refines deicing film that allows radio frequencies to pass Rice university scientists who created a deicing film for radar domes have refined now the technology to work as a transparent coating for glass.
The new work by Rice chemist James Tour and his colleagues could keep glass surfaces from windshields to skyscrapers free of ice
and fog while retaining their transparency to radio frequencies (RF). The technology was introduced this month in the American Chemical Society journal Applied materials and Interfaces.
The material is made of graphene nanoribbons atom-thick strips of carbon created by splitting nanotubes a process also invented by the Tour lab
. Whether sprayed painted or spin-coated the ribbons are transparent and conduct both heat and electricity.
Last year the Rice group created films of overlapping nanoribbons and polyurethane paint to melt ice on sensitive military radar domes
which need to be kept clear of ice to keep them at peak performance. The material would replace a bulky and energy-hungry metal oxide framework.
The graphene-infused paint worked well Tour said but where it was thickest it would break down
when exposed to high-powered radio signals. At extremely high RF the thicker portions were absorbing the signal he said.
That caused degradation of the film. Those spots got so hot that they burned up.
The answer was to make the films more consistent. The new films are between 50 and 200 nanometers thick a human hair is about 50000 nanometers thick
and retain their ability to heat when a voltage is applied. The researchers were also able to preserve their transparency.
but can be used to coat glass and plastic as well as radar domes and antennas. In the previous process the nanoribbons were mixed with polyurethane
but testing showed the graphene nanoribbons themselves formed an active network when applied directly to a surface.
They were coated subsequently with a thin layer of polyurethane for protection. Samples were spread onto glass slides that were iced then.
when kept in a minus-20-Degree celsius environment the researchers reported. One can now think of using these films in automobile glass as an invisible deicer
and even in skyscrapers Tour said. Glass skyscrapers could be kept free of fog and ice but also be transparent to radio frequencies.
It's really frustrating these days to find yourself in a building where your cellphone doesn't work.
This could help alleviate that problem. Tour noted future generations of long-range Wi-fi may also benefit.
It's going to be important as Wi-fi becomes more ubiquitous especially in cities. Signals can't get through anything that's metallic in nature
but these layers are so thin they won't have any trouble penetrating. He said nanoribbon films also open a path toward embedding electronic circuits in glass that are both optically and RF transparent a
#For electronics beyond silicon a new contender emerges Silicon has few serious competitors as the material of choice in the electronics industry.
Yet transistors, the switchable valves that control the flow of electrons in a circuit, cannot simply keep shrinking to meet the needs of powerful, compact devices;
physical limitations like energy consumption and heat dissipation are too significant. Now, using a quantum material called a correlated oxide,
Harvard researchers have achieved a reversible change in electrical resistance of eight orders of magnitude, a result the researchers are calling"colossal."
a laboratory usually devoted to studying fuel cellshe kind that run on methane or hydrogened by Shriram Ramanathan, Associate professor of Materials science at the Harvard School of engineering and Applied sciences (SEAS.
it would be easy to integrate them into existing electronic devices and fabrication methods. The discovery, published in Nature Communications,
therefore firmly establishes correlated oxides as promising semiconductors for future three-dimensional integrated circuits as well as for adaptive, tunable photonic devices.
Challenging silicon Although electronics manufacturers continue to pack greater speed and functionality into smaller packages the performance of silicon-based components will soon hit a wall."
"Traditional silicon transistors have fundamental scaling limitations, "says Ramanathan.""If you shrink them beyond a certain minimum feature size,
they don't quite behave as they should.""Yet silicon transistors are hard to beat, with an on/off ratio of at least 10 4 required for practical use."
"It's a pretty high bar to cross, "Ramanathan explains, adding that until now, experiments using correlated oxides have produced changes of only about a factor of 10,
But Ramanathan and his team have crafted a new transistor, made primarily of an oxide called samarium nickelate,
that in practical operation achieves an on/off ratio of greater than 10 5hat is, comparable to state-of-the-art silicon transistors.
In future work the researchers will investigate the device's switching dynamics and power dissipation;
"Our orbital transistor could really push the frontiers of this field and say, you know what?
which is a foundational step in the use of any semiconductor, "says Ramanathan. Doping is the process of introducing different atoms into the crystal structure of a material,
and it affects how easily electrons can move through ithat is, to what extent it resists or conducts electricity.
Doping typically effects this change by increasing the number of available electrons, but this study was different.
The Harvard team manipulated the band gap, the energy barrier to electron flow.""By a certain choice of dopantsn this case, hydrogen or lithiume can widen
or narrow the band gap in this material, deterministically moving electrons in and out of their orbitals,
That's a fundamentally different approach than is used in other semiconductors. The traditional method changes the energy level to meet the target;
the new method moves the target itself. In this orbital transistor, protons and electrons move in or out of the samarium nickelate when an electric field is applied, regardless of temperature,
so the device can be operated in the same conditions as conventional electronics. It is solid-state,
meaning it involves no liquids, gases, or moving mechanical parts. And, in the absence of power, the material remembers its present staten important feature for energy efficiency."
"That's the beauty of this work,"says Ramanathan.""It's an exotic effect, but in principle it's highly compatible with traditional electronic devices."
"Quantum materials Unlike silicon, samarium nickelate and other correlated oxides are quantum materials, meaning that quantum-mechanical interactions have a dominant influence over the material propertiesnd not just at small scales."
"If you have two electrons in adjacent orbitals, and the orbitals are filled not completely, in a traditional material the electrons can move from one orbital to another.
But in the correlated oxides, the electrons repulse each other so much that they cannot move, "Ramanathan explains."
"The occupancy of the orbitals and the ability of electrons to move in the crystal are tied very closely togetherr'correlated.'
'Fundamentally, that's what dictates whether the material behaves as an insulator or a metal."
Similarly, samarium nickelate is likely to catch the attention of applied physicists developing photonic and optoelectronic devices."
"Opening and closing the band gap means you can now manipulate the ways in which electromagnetic radiation interacts with your material,
and joined the faculty of Rensselaer Polytechnic institute this fall.""Just by applying an electric field, you're dynamically controlling how light interacts with this material."
"Further ahead, Researchers at the Center for Integrated Quantum Materials, established at Harvard in 2013 through a grant from the National Science Foundation,
aim to develop an entirely new class of quantum electronic devices and systems that will transform signal processing and computation.
Ramanathan compares the current state of quantum materials research to the 1950s, when transistors were invented newly
and physicists were still making sense of them.""We are basically in that era for these new quantum materials,
#The future face of molecular electronics The emerging field of molecular electronics could take our definition of portable to the next level enabling the construction of tiny circuits from molecular components.
In these highly efficient devices individual molecules would take on the roles currently played by comparatively-bulky wires resistors and transistors.
A team of researchers from five Japanese and Taiwanese universities has identified a potential candidate for use in small-scale electronics:
Picene's sister molecule pentacene has been studied widely because of its high carrier mobilityts ability to quickly transmit electrons a critical property for nanoscale electronics.
To test picene's properties when juxtaposed with a metal as it would be in an electronic device the researchers deposited a single layer of picene molecules onto a piece of silver.
and metal surfaces we found that the zigzag-shaped picene basically just sits on the silver said University of Tokyo researcher Yukio Hasegawa.
The weak interaction is advantageous for molecular electronics applications because the modification of the properties of molecular thin film by the presence of the silver is negligible
According to Hasegawa picene's weak interactions with the silver allow it to deposit directly on the surface without a stabilizing layer of molecules between a quality he said is essential for achieving high-quality contact with metal electrodes.
Because picene displays its high carrier mobility when exposed to oxygen the researchers hope to investigate its properties under varying levels of oxygen exposure
#Study sheds new light on why batteries go bad A comprehensive look at how tiny particles in a lithium ion battery electrode behave shows that rapid-charging the battery
and using it to do high-power rapidly draining work may not be as damaging as researchers had thought
The results challenge the prevailing view that supercharging batteries is always harder on battery electrodes than charging at slower rates according to researchers from Stanford university and the Stanford Institute for Materials & Energy Sciences (SIMES) at the Department of energy's SLAC National Accelerator Laboratory.
They also suggest that scientists may be able to modify electrodes or change the way batteries are charged to promote more uniform charging
and discharging and extend battery life. The fine detail of what happens in an electrode during charging
and discharging is just one of many factors that determine battery life but it's one that until this study was understood not adequately said William Chueh of SIMES an assistant professor at Stanford's Department of Materials science and engineering and senior author of the study.
We have found a new way to think about battery degradation. The results he said can be applied directly to many oxide
and graphite electrodes used in today's commercial lithium ion batteries and in about half of those under development.
His team described the study September 14 2014 in Natural Materials. The team included collaborators from Massachusetts institute of technology Sandia National Laboratories Samsung Advanced Institute of technology America and Lawrence Berkeley National Laboratory.
One important source of battery wear and tear is the swelling and shrinking of the negative and positive electrodes as they absorb
and release ions from the electrolyte during charging and discharging. For this study scientists looked at a positive electrode made of billions of nanoparticles of lithium iron phosphate.
If most or all of these particles actively participate in charging and discharging they'll absorb
and release ions more gently and uniformly. But if only a small percentage of particles sop up all the ions they're more likely to crack
and get ruined degrading the battery's performance. Previous studies produced conflicting views of how the nanoparticles behaved.
To probe further researchers made small coin cell batteries charged them with different levels of current for various periods of time quickly took them apart
and rinsed the components to stop the charge/discharge process. Then they cut the electrode into extremely thin slices
and took them to Berkeley Lab for examination with intense X-rays from the Advanced Light source synchrotron a DOE Office of Science User Facility.
We were able to look at thousands of electrode nanoparticles at a time and get snapshots of them at different stages during charging
and discharging said Stanford graduate student Yiyang Li lead author of the report. This study is the first to do that comprehensively under many charging
and discharging conditions. Analyzing the data using a sophisticated model developed at MIT the researchers discovered that only a small percentage of nanoparticles absorbed and released ions during charging even
when it was done very rapidly. But when the batteries discharged an interesting thing happened: As the discharge rate increased above a certain threshold more and more particles started to absorb ions simultaneously switching to a more uniform and less damaging mode.
This suggests that scientists may be able to tweak the electrode material or the process to get faster rates of charging
and discharging while maintaining long battery life. The next step Li said is to run the battery electrodes through hundreds to thousands of cycles to mimic real-world performance.
The scientists also hope to take snapshots of the battery while it's charging and discharging rather than stopping the process and taking it apart.
This should yield a more realistic view and can be done at synchrotrons such as ALS or SLAC's Stanford Synchrotron radiation Lightsource also a DOE Office of Science User Facility.
Li said the group has also been working with industry to see how these findings might apply in the transportation and consumer electronics sectors.
Explore further: Live from inside a battery: Researchers observe the phenomenon of'lithium plating'during the charging process More information:
W. Chueh et al. Nature Materials 14 september 2014. DOI: 10.1038/NMAT408 8
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