Lawrence Berkeley Lab team helps lead “+Charge-” to Revolutionize Energy Storage


1-Berkley Storage AR-141119272

Venkat Srinivasan, right, staff scientist in the Environmental Energy Technologies Division, talks about some of the new features as Project Director Richard C. Stanton listens in during a tour of the new General Purpose Laboratory at the Lawrence Berkeley Laboratory in Berkeley, Calif., on Tuesday, Oct. 28, 2014. The GPL, otherwise known as Building 33, is a new facility dedicated to pursuing research in energy storage and renewable energy. (Laura A. Oda/Bay Area News Group)

BERKELEY — Imagine an electric car with the range of a Tesla Model S — able to reach Lake Tahoe from the Bay Area on a single charge — but at one-fifth the $70,000 price tag for the luxury sedan.

Or a battery not only able to provide many times more energy than today’s technology but also at significantly cheaper prices, meaning longer-lasting and less expensive power for cellphones, laptops and even the home.

Those are among the ambitious goals of the $120 million, Department of Energy-funded Joint Center for Energy Storage Research, a 14-member partnership led by Argonne National Laboratory and including Lawrence Berkeley Lab, Sandia National Laboratories and a host of universities and private companies. In January, the center’s Berkeley hub is moving into the lab’s new $54 million General Purpose Laboratory, bringing its battery scientists, chemists and engineers together under one roof for the first time.1-yellow_electric_car_charger

The team, headed by JCESR Deputy Director Venkat Srinivasan, aims to achieve revolutionary advances in battery performance — creating devices with up to five times the energy capacity of today’s batteries at one-fifth the cost by 2017.

To accomplish the feat, Srinivasan is looking to replace the current standard-bearer for rechargeable batteries — lithium-ion — with batteries made of cheaper, more durable materials, including magnesium, aluminum and calcium.

“We want to go beyond and find the next generation of technology,” Srinivasan said. “It’s clear to us that the batteries we have today are not meeting the needs.”

While private companies such as Tesla and Toyota are working to improve on lithium-ion technology, in the United States it’s the government labs that are trying to move technology to the next level.

“There’s a real opportunity for next-generation storage,” Crabtree said. “You have to make a big step forward. Lithium-ion will not be able to make that step. … You need a big program and a group effort to make it happen.”

Nearly two years into the project, Crabtree said, researchers have narrowed down a list of about 100 types of “beyond lithium-ion” batteries to a handful of promising concepts that are already in the prototype phase.

In order to reach the Obama administration’s goals of producing a quarter of all the nation’s electricity from solar and wind by 2025, and having 1 million all-electric vehicles on the road in the coming years, consumers will need cheaper batteries with a higher energy density, faster charging time and more range, said Lawrence Berkeley Lab’s Srinivasan. A battery costing $100 per kilowatt hour — three to five times cheaper than today’s technology — would make electric vehicles and renewable energy affordable to the masses.

“Energy storage is a linchpin of the future,” Srinivasan said. “Today’s batteries are kind of expensive. How do we get it to the point where the battery can pay for itself? That’s the target we’re shooting for.”

Sharing the new state-of-the-art General Purpose Laboratory will be JCESR principal investigator and Lawrence Berkeley staff scientist Brett Helms, who is focusing his research on flow batteries, a type of large-scale rechargeable battery that stores energy in a liquid solution of electrolytes that can be pumped through a membrane, generating power when they circulate and react with electrodes.

Helms wants to use more cost-effective materials such as sulfur — a plentiful byproduct of refining crude oil — to create a battery with five to 10 times more energy than current flow batteries, at a much lower cost. Combined with solar panels and wind farms, massive high-density battery packs could store most of the energy generated for use at a later time, providing an uninterrupted power supply in homes day or night, rain or shine, allowing homeowners to go off-the-grid and access the energy at any time.

This would overcome one of the main problems with renewable systems: They can only produce energy when the conditions — sun or wind — are right, not necessarily when the energy is needed, as fossil fuel-fired generators do.

“We’re producing all of this energy, but where is it going to go and how is it going to be integrated into the grid?” Helms said. “The biggest concern is to take advantage of the investment we’ve been making in the renewables. If we don’t have an energy storage solution, we will have wasted that investment.”

Helms’ team is developing a membrane for the flow battery that would increase its durability and enable the battery to cycle, or charge, better. He aims to have a working prototype of a lithium-sulfur flow battery — the first of its kind — by the end of the five-year initiative. The technology, he said, could also someday power electric vehicles.

“We’ve done battery work in the past, but thinking about national problems with people all over the country is an amazing opportunity,” Helms said.

The future home of Berkeley’s battery research hub is next door to the Advanced Light Source building, where automaker Toyota has been researching magnesium-ion batteries.

Whereas lithium-ion batteries have a charge of +1, providing a single electron per electrical current, magnesium has a charge of +2.

“For the same weight, you can have twice the charge — you’re doubling the amount of capacity,” Srinivasan said. “That’s exciting.”

Using high-performance computing, Srinivasan’s team has whittled down the number of materials to a few that have sufficient energy capacity and can be classified as safe, cheaper and longer-lasting than lithium. Within the next year, Srinivasan hopes to have other new materials ready for testing, and optimized prototypes ready by 2017.

George Crabtree, director of JCESR at Argonne National Laboratory near Chicago, said the federal government is pursuing the research to dramatically transform the two areas that consume two-thirds of all the energy generated in the United States — transportation and the energy grid. If successful, Crabtree said, consumers would benefit with cheaper electric cars and less dependence on utility companies for power at home.

Tucson News: Synthetic Biology Market Expected to Reach $5.6 Billion in 2018


BioGraphene-320This article was originally distributed via PRWeb. PRWeb, WorldNow and this Site make no warranties or representations in connection therewith.

SOURCE:

The synthetic biology market is highly competitive with a large number of players, including both big and small players, operating in this market. http://www.marketsandmarkets.com/Market-Reports/synthetic-biology-market-889.html

(PRWEB) November 20, 2014

The report, “Synthetic Biology Market by Tool (XNA, Chassis, Oligos, Enzymes, Cloning kits), Technology (Bioinformatics, Nanotechnology, Gene Synthesis, Cloning & Sequencing), Application (Biofuels, Pharmaceuticals, Biomaterials, Bioremediation) – Global Forecast to 2018”, analyses and studies the major market drivers, threats, opportunities, and challenges.

This report studies the global synthetic biology market for the forecast period of 2013 to 2018. This market is expected to reach $5,630.4 million by 2018 from $1,923.1 million in 2013, growing at a CAGR of 24% during the forecast period.

The global synthetic biology market is segmented on the basis of tools, technologies, applications, and geographies.

On the basis of tools, the synthetic biology market is categorized into Xeno-nucleic acids, chassis organisms, oligonucleotides, enzymes, and cloning and assembly kits. The oligonucleotides segment accounted for a major share of the synthetic biology market, by tool, in 2013.

On the basis of technologies, the synthetic biology market is segmented into enabled and enabling technologies. Enabling technologies accounted for a major share of the synthetic biology market in 2013. On the basis of applications, the synthetic biology market is segmented into environmental, medical, and industrial applications. The medical applications segment accounted for a major share of the synthetic biology market in 2013.

On the basis of regions, the market is divided into North America, Europe, Asia, and Rest of the World (RoW). The Rest of the World region comprises Latin America, Pacific countries, and the Middle East and Africa. North America accounted for the largest share of the synthetic biology market, followed by Europe and Asia. However, the European market is expected to grow at the highest CAGR in the coming five years, and serves as a revenue pocket for the companies involved in the manufacturing of synthetic biology products.

Over the years, the demand for synthetic biology is likely to increase owing to the increasing R&D expenditure in pharmaceutical and biotechnology companies, growing demand for synthetic genes, rising production of genetically modified crops, and incessantly rising funding in the field of synthetic biology. However, ethical and social issues such as bio-safety and bio-security are major factors that are restricting the growth of this market. Furthermore, rising concerns over fuel consumption and increasing demand for protein therapeutics are likely to create opportunities for the synthetic biology market. However, standardization and integration of biological parts at system-level still remains a challenge for this market.

Some of the major players in the global synthetic biology market include Amyris, Inc. (U.S.), DuPont (U.S.), GenScript USA, Inc. (U.S.), Intrexon Corporation (U.S.), Integrated DNA Technologies (IDT) (U.S.), New England Biolabs, Inc. (NEB) (U.S.), Novozymes (Denmark), Royal DSM (Netherlands), Synthetic Genomics, Inc. (California), and Thermo Fisher Scientific, Inc. (U.S.).

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Silver Nanowire Ink Printed on Paper to Create Flexible Electronic Sensors


Nano Skin SensorsFlexible electronic sensors based on paper — an inexpensive material — have the potential to some day cut the price of a wide range of medical tools, from helpful robots to diagnostic tests.

Scientists have now developed a fast, low-cost way of making these sensors by directly printing conductive ink on paper. They published their advance in the journal ACS Applied Materials & Interfaces.

Anming Hu and colleagues point out that because paper is available worldwide at low cost, it makes an excellent surface for lightweight, foldable electronics that could be made and used nearly anywhere. Scientists have already fabricated paper-based point-of-care diagnostic tests and portable DNA detectors. But these require complicated and expensive manufacturing techniques. Silver nanowire ink, which is highly conductive and stable, offers a more practical solution. Hu’s team wanted to develop a way to print it directly on paper to make a sensor that could respond to touch or specific molecules, such as glucose.

Rice Sensors nanophotonic

The researchers developed a system for printing a pattern of silver ink on paper within a few minutes and then hardening it with the light of a camera flash. The resulting device responded to touch even when curved, folded and unfolded 15 times, and rolled and unrolled 5,000 times. The team concluded their durable, lightweight sensor could serve as the basis for many useful applications.

Source: http://www.acs.org/

Big Innovations Are Happening in Tiny Packages


We’re not supposed to judge a book by its cover nor should we judge an entrepreneur on the physical size of his or her work.

In the world of nanotechnology, big things are happening in tiny packages.

If you’re not deep into science and tech geekdom, nanotechnology essentially is the manipulation of matter at molecular and submolecular levels to create products that never existed before. It can also involve improving everyday items to make them more durable and lighter.

That’s the beauty of science — improving and creating new things in ways we never could imagine. And with innovation comes huge opportunity for science-minded entrepreneurs.

“You have innovators and researchers who are not only developing new concepts … some of them take that know-how and translate it to business and entrepreneurship,” says Alain Kaloyeros, a professor of nanoscience and CEO of New York’s SUNY Polytechnic Institute.

Entrepreneur visited SUNY’s College of Nanoscale Science and Engineering in Albany, N.Y., where we spoke with several entrepreneurs who have built businesses from the innovations they are creating in science labs.

Check out the short video above to find out what these brilliant minds are up to.

Related: In Nanotech’s Small World, Big Opportunities Abound

New 2-D quantum materials for nanoelectronics


new2dquantumResearchers at MIT say they have carried out a theoretical analysis showing that a family of two-dimensional materials exhibits exotic quantum properties that may enable a new type of nanoscale electronics.

These are predicted to show a phenomenon called the quantum spin Hall (QSH) effect, and belong to a class of materials known as , with layers a few atoms thick. The findings are detailed in a paper appearing this week in the journal Science, co-authored by MIT postdocs Xiaofeng Qian and Junwei Liu; assistant professor of physics Liang Fu; and Ju Li, a professor of nuclear science and engineering and materials science and engineering.

QSH materials have the unusual property of being electrical insulators in the bulk of the material, yet highly conductive on their edges. This could potentially make them a suitable material for new kinds of quantum , many researchers believe.

new2dquantum

This diagram illustrates the concept behind the MIT team’s vision of a new kind of electronic device based on 2-D materials. The 2-D material is at the middle of a layered “sandwich,” with layers of another material, boron nitride, at top and …more

But only two materials with QSH properties have been synthesized, and potential applications of these materials have been hampered by two serious drawbacks: Their bandgap, a property essential for making transistors and other electronic devices, is too small, giving a low signal-to-noise ratio; and they lack the ability to switch rapidly on and off. Now the MIT researchers say they have found ways to potentially circumvent both obstacles using 2-D materials that have been explored for other purposes.

Existing QSH materials only work at very low temperatures and under difficult conditions, Fu says, adding that “the materials we predicted to exhibit this effect are widely accessible. … The effects could be observed at relatively high temperatures.”

“What is discovered here is a true 2-D material that has this [QSH] characteristic,” Li says. “The edges are like perfect quantum wires.”

The MIT researchers say this could lead to new kinds of low-power quantum electronics, as well as spintronics devices—a kind of electronics in which the spin of electrons, rather than their electrical charge, is used to carry information.

Graphene, a two-dimensional, one-atom-thick form of carbon with unusual electrical and mechanical properties, has been the subject of much research, which has led to further research on similar 2-D materials. But until now, few researchers have examined these materials for possible QSH effects, the MIT team says. “Two-dimensional materials are a very active field for a lot of potential applications,” Qian says—and this team’s theoretical work now shows that at least six such materials do share these QSH properties.

The MIT researchers studied materials known as transition metal dichalcogenides, a family of compounds made from the transition metals molybdenum or tungsten and the nonmetals tellurium, selenium, or sulfur. These compounds naturally form thin sheets, just atoms thick, that can spontaneously develop a dimerization pattern in their crystal structure. It is this lattice dimerization that produces the effects studied by the MIT team.

While the new work is theoretical, the team produced a design for a new kind of transistor based on the calculated effects. Called a topological field-effect transistor, or TFET, the design is based on a single layer of the 2-D material sandwiched by two layers of 2-D boron nitride. The researchers say such devices could be produced at very high density on a chip and have very low losses, allowing high-efficiency operation.

By applying an electric field to the material, the QSH state can be switched on and off, making possible a host of electronic and spintronic devices, they say.

In addition, this is one of the most promising known materials for possible use in quantum computers, the researchers say. Quantum computing is usually susceptible to disruption—technically, a loss of coherence—from even very small perturbations. But, Li says, topological quantum computers “cannot lose coherence from small perturbations. It’s a big advantage for quantum information processing.”

Because so much research is already under way on these 2-D materials for other purposes, methods of making them efficiently may be developed by other groups and could then be applied to the creation of new QSH electronic devices, Qian says.

Nai Phuan Ong, a professor of physics at Princeton University who was not connected to this work, says, “Although some of the ideas have been mentioned before, the present system seems especially promising. This exciting result will bridge two very active subfields of condensed matter physics, topological insulators and dichalcogenides.”

Explore further: ‘Topological insulators’ promising for spintronics, quantum computers

Titanium Dioxide Nanotubes for Dye-Sensitized Solar Cells: Improving Efficiencies


16-CNT Dye Solar Cells figure1Titanium dioxide (TiO2) has distinct properties. It is a semiconductor that is photocatalytic, non-toxic, biocompatible and easy to fabricate. This makes it attractive for a wide range of applications such as sensors, human implants and dye-sensitized solar cells (DSSCs). In DSSCs, the one-dimensional (1D) structure of TiO2 nanotubes provides a direct pathway for electrons up to the collecting electrode. It also has fewer trapping sites than conventional structures. Highly ordered TiO2 nanotubes are required for more efficient devices and, reporting in Nanotechnology, researchers have investigated the factors influencing this.

Here, highly ordered TiO2 nanotube arrays are synthesized using the electrochemical anodization of Ti foils subjected to an electropolishing pre-treatment. The researchers unveil the decisive role played by the electropolishing of the Ti foil on the anodic TiO2 nanotubes to obtain a hexagonal closed-packed array distribution.

Surface ‘waviness’

Besides the usual advantages, such as size control, the electropolishing surface “waviness” improves the organization of anodic oxide nanopores or nanotubes. This new overriding application of electropolishing creates nanopatterns in the surface of titanium. This works as a pre-pattern prior to the anodization and ultimately leads to highly ordered oxide nanostructures.

Improving organization

A multidisciplinary team, which includes researchers from the Universidade do Porto in Portugal, studied the prior-anodization Ti surface topography with different electropolishing potentials. Optimized Ti surfaces with lower roughness and topographic nanopatterning are obtained. These lead to fast growth rates of nanotubes with higher organization (ideal hexagonal closed-packed array distribution).

The researchers found that the Ti surface roughness plays an important role in the onset of pore nucleation in enhancing the local focusing effect of the electrical field. Additionally, the electropolishing induces periodic dimple structures on the metal surface. This leads to a preferential ordered pore nucleation, offering an organization improvement of the anodic oxide NTs.

More information about this research can be found in the journal Nanotechnology 25 485301 (IOPselect article).

Further reading

Improving the performance of dye-sensitized solar cells at larger cell sizes (Jan 2013)
Nb-doped titania electrode helps make good solar cell (Oct 2013)
Patterning bumpy surfaces (July 2014)

About the author

Arlete Apolinário is a PhD student at the IFIMUP and IN- Institute of Nanoscience and Nanotechnology, from Universidade do Porto in Portugal. With a background in materials physics, her current research interests focus on nanostructured semiconductors (titania and hematite nanotubes) synthesis for photoelectrochemical and dye-sensitized solar cells.

The Speed of Light – “Switch” – Genesis Nanotechnology Online News & Updates


seo-speed-of-lightScientists have developed a light source which converts an electrical voltage pulse into a light pulse by means of a single molecule, possibly serving as a prototype for nano-components that convert electrical into optical signals with gigahertz frequencies.

Information is processed and transmitted by ever-smaller components, sometimes with electrons and sometimes with light. Scientists at the Max Planck Institute for Solid State Research in Stuttgart have now developed a light source which converts an electrical voltage pulse into a light pulse by means of a single molecule. Here the molecule functions as a transistor-controlled light switch which even allows the intensity of the light to be regulated.

Read the Full Article Here:

https://www.linkedin.com/pulse/article/20141120195303-84631162-speed-of-light-switch-genesis-nanotechnology-nano-news?trk=object-title

For More Articles, News and Updates Please Read Our Online Newspaper:

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NREL Teams with SolarCity to Maximize Solar Power on Electrical Grids


NREL 20140609_buildings_26954_hpWorking together with the Hawaiian Electric Companies to analyze and enable higher penetrations of distributed solar energy systems in Hawaii.

November 20, 2014

The Energy Department’s National Renewable Energy Laboratory (NREL) and SolarCity have entered into a cooperative research agreement to address the operational issues associated with large amounts of distributed solar energy on electrical grids. The work includes collaboration with the Hawaiian Electric Companies to analyze high penetration solar scenarios using advanced modeling and inverter testing at the Energy Systems Integration Facility (ESIF). The project is funded in part through an Energy Department solar cost-share program.

NREL 20140609_buildings_26954_hp

The ESIF on NREL’s Golden, Colorado campus, houses a broad array of capabilities and laboratories focused on energy integration research including megawatt-scale power hardware-in-the-loop testing, which will allow researchers to analyze the behavior of distributed electricity generation and distribution devices while connected to a testing system that dynamically emulates the characteristics of a power system. Testing with SolarCity and Hawaiian Electric at ESIF will cover the dynamics between inverter-based assets on a grid system, voltage regulation, and bi-directional power flows. Scientists and engineers from SolarCity and Hawaiian Electric were at NREL in September to kick off the research project and in October for a follow-up meeting.

NREL has completed load rejection over voltage (LRO) testing and will be completing ground fault overvoltage testing shortly. This testing will allow Hawaiian Electric to approve photovoltaic (PV) deployments to customers who have been waiting for interconnection on these high penetration solar circuits.

“This is an excellent opportunity to utilize ESIF’s unique power hardware-in-the-loop capability with inverter-based assets,” NREL Director of Partnerships for Energy Systems Integration Martha Symko-Davies said.  “This capability will be used to help utilities evaluate the impact of distributed energy resources like solar technologies on distribution systems and help them find solutions to utilizing these technologies in a safe, reliable, and cost-effective manner at scale.”

NREL will also evaluate SolarCity’s PV generation curtailment hardware and software based on the potential need for PV power curtailment, or the use of less solar power than is available at a specific time, through a remote signal.

Hawaiian Electric is partnering with NREL and SolarCity throughout the process, providing technical input on testing and setup, as well feedback on results.

“SolarCity is committed to ensuring that solar is an asset to grid operators, and this partnership will take us further towards that goal,” SolarCity Chief Technology Officer Peter Rive said.

“We know how important the option of solar is for our customers. Solving these issues takes everyone-utilities, the solar industry and other leading technical experts like NREL-working together. That’s what this work is all about,” Hawaiian Electric Vice President for Energy Delivery Colton Ching said.  “With the highest amount of solar in the nation, our utilities are facing potential reliability and safety issues before anywhere else.”

The research was supported by the Office of Energy Efficiency and Renewable Energy’s Grid Integration Initiative. Funding was equally shared between Solar City and the Energy Department’s SunShot Initiative.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

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Visit NREL online at www.nrel.gov

Scientists Develop a Nanolamp with a Lightning-Fast Switch


A-Nanolamp-with-Lightning-Fast-SwitchScientists have developed a light source which converts an electrical voltage pulse into a light pulse by means of a single molecule, possibly serving as a prototype for nano-components that convert electrical into optical signals with gigahertz frequencies.

Information is processed and transmitted by ever-smaller components, sometimes with electrons and sometimes with light. Scientists at the Max Planck Institute for Solid State Research in Stuttgart have now developed a light source which converts an electrical voltage pulse into a light pulse by means of a single molecule. Here the molecule functions as a transistor-controlled light switch which even allows the intensity of the light to be regulated. Since the molecular switch allows the light to be switched on and off extremely fast, the light source could serve as a prototype for nano-components that convert electrical into optical signals with gigahertz frequencies.

A-Nanolamp-with-Lightning-Fast-Switch

Researchers at the Max Planck Institute for Solid State Research apply a voltage between a gold surface coated with a layer of spherical carbon molecules and the tip of a scanning tunneling microscope. The resulting electric field (indicated by the grey arrows in the diagram) can be regulated by the level of the voltage and the distance between the tip and the metal surface. With a particular field strength, the single molecule (in magenta) becomes electrically charged, which immediately leads to electrical energy being converted to light (the yellow wave). Credit: MPI for Solid State Research

Today, organic dyes do not just provide color for carpets, newspapers or clothing when light shines on them. Now they themselves shine in electric light sources, in organic light-emitting diodes (OLEDs), like those in smartphone screens. However, the displays still contain transistors for regulating the brightness alongside the actual light sources (pixels). A team from the Max Planck Institute for Solid State Research, the Max Planck EPFL Center and the Karlsruhe Institute of Technology, has now combined the two functions in a single molecule.

The researchers working with Klaus Kern, Director of the Stuttgart-based Max Planck Institute, construct their nanolamp with integrated transistor control by placing a dye molecule on a layer of Buckminsterfullerenes – which are spherical carbon molecules. The layer of carbon spheres coats a metal carrier, in this case of gold, which serves as an electrode. “As the second electrode above the dye molecule, we use the tip of a scanning tunneling microscope,” says Klaus Kuhnke. “But a second metal layer would also be suitable.” However, the researchers were only able to discover the astonishing properties of the individual molecule because they used a movable tip for their investigation. What they actually did was to scan the surface with the tip, measuring the light emitted at the same time. “In the process we observed that light is produced on the dye molecules,” according to Kuhnke.

The voltage first produces light waves which are trapped on the metal surface

The researchers now regulate the electric field on the molecule with an electrical voltage between the gold carrier and the tip of the scanning tunneling microscope (STM), as well as the distance between the two electrical contacts. If this exceeds 2.5 volts per nanometer, the lamp is switched on. The molecule, however, does not just switch the light on and off. It actually allows continuous regulation of the light intensity, getting brighter and darker over a very narrow band of a few millivolts. It thus functions in this range similarly to a light-emitting transistor.

The electrical energy is not converted directly into light energy in the switching process, but indirectly via “plasmons”. These can be imagined as light waves that are trapped on the metallic surface and may be radiated by such things as surface irregularities. With their help, more information can be transmitted or processed in a small space in the form of light than with light alone: plasmons can run along metal tracks which are narrower than 100 nanometers, whereas optical fibers, for instance, must be at least half as wide as the wavelength of the light they transmit.

The switching process takes less than a billionth of a second

The organic molecule plays a decisive role in the generation of the trapped and radiated light waves on the metal surface: a minimal change in the electric field at the location of the molecule decides whether light is produced or not. This makes the nanolamp interesting for the transfer of digital information with light, where “light on” stands for the one of a data bit and “light off” for the zero. “A small modulation of the electric field at the molecule produces a bit stream that is emitted as light and can transfer a message,” says Klaus Kuhnke. And since a light source above the threshold value turns on with a tiny change in voltage, the switching process takes place extremely quickly: It takes less than a billionth of a second, and so may eventually permit data transfers with bit rates in the gigahertz range.

The control of the intensity of the light by a single molecule is decisive for the speed of the light switch. Mechanical light switches are operated by a lever, and the heavier this lever is the more effort it takes to move the switch from one switching position to another. These clumsy levers correspond in electronics to unavoidable capacitances which swallow a part of the current without producing any light. The larger the light-switching element is, the more time and energy is required to charge the “parasitic” capacitors. Here the minute size of the molecule helps: It costs hardly any additional energy to charge the environment of a single molecule the size of a millionth of a millimeter with a tiny voltage of a few millivolts – the switching process is correspondingly fast. “Such a molecular light source thus promises to become a new, efficient component for information transmission – especially as the light produced may still be weak, but is clearly perceptible with the naked eye,” says Klaus Kuhnke.

Publication: Christoph Große, et al., “Dynamic Control of Plasmon Generation by an Individual Quantum System,” Nano Letters, 2014, 14 (10), pp 5693–5697; DOI: 10.1021/nl502413k

Source: Max Planck Institute

Image: MPI for Solid State Research

Two sensors in one: Nanoparticles that enable both MRI and fluorescent imaging could monitor cancer, other diseases


12-Sensors 141118125600-largeNovember 18, 2014 Source: Massachusetts Institute of Technology

MIT chemists have developed new nanoparticles that can simultaneously perform magnetic resonance imaging (MRI) and fluorescent imaging in living animals. Such particles could help scientists to track specific molecules produced in the body, monitor a tumor’s environment, or determine whether drugs have successfully reached their targets.

In a paper appearing in the Nov. 18 issue of Nature Communications, the researchers demonstrate the use of the particles, which carry distinct sensors for fluorescence and MRI, to track vitamin C in mice. Wherever there is a high concentration of vitamin C, the particles show a strong fluorescent signal but little MRI contrast. If there is not much vitamin C, a stronger MRI signal is visible but fluorescence is very weak.

Future versions of the particles could be designed to detect reactive oxygen species that often correlate with disease, says Jeremiah Johnson, an assistant professor of chemistry at MIT and senior author of the study. They could also be tailored to detect more than one molecule at a time.

12-Sensors 141118125600-large

MIT chemists have developed new nanoparticles that can simultaneously perform magnetic resonance imaging (MRI) and fluorescent imaging in living animals.
Credit: Illustration by Christine Daniloff/MIT

“You may be able to learn more about how diseases progress if you have imaging probes that can sense specific biomolecules,” Johnson says.

Dual action

Johnson and his colleagues designed the particles so they can be assembled from building blocks made of polymer chains carrying either an organic MRI contrast agent called a nitroxide or a fluorescent molecule called Cy5.5.

When mixed together in a desired ratio, these building blocks join to form a specific nanosized structure the authors call a branched bottlebrush polymer. For this study, they created particles in which 99 percent of the chains carry nitroxides, and 1 percent carry Cy5.5.

Nitroxides are reactive molecules that contain a nitrogen atom bound to an oxygen atom with an unpaired electron. Nitroxides suppress Cy5.5’s fluorescence, but when the nitroxides encounter a molecule such as vitamin C from which they can grab electrons, they become inactive and Cy5.5 fluoresces.

Nitroxides typically have a very short half-life in living systems, but University of Nebraska chemistry professor Andrzej Rajca, who is also an author of the new Nature Communications paper, recently discovered that their half-life can be extended by attaching two bulky structures to them. Furthermore, the authors of the Nature Communications paper show that incorporation of Rajca’s nitroxide in Johnson’s branched bottlebrush polymer architectures leads to even greater improvements in the nitroxide lifetime. With these modifications, nitroxides can circulate for several hours in a mouse’s bloodstream — long enough to obtain useful MRI images.

The researchers found that their imaging particles accumulated in the liver, as nanoparticles usually do. The mouse liver produces vitamin C, so once the particles reached the liver, they grabbed electrons from vitamin C, turning off the MRI signal and boosting fluorescence. They also found no MRI signal but a small amount of fluorescence in the brain, which is a destination for much of the vitamin C produced in the liver. In contrast, in the blood and kidneys, where the concentration of vitamin C is low, the MRI contrast was maximal.

Mixing and matching

The researchers are now working to enhance the signal differences that they get when the sensor encounters a target molecule such as vitamin C. They have also created nanoparticles carrying the fluorescent agent plus up to three different drugs. This allows them to track whether the nanoparticles are delivered to their targeted locations.

“That’s the advantage of our platform — we can mix and match and add almost anything we want,” Johnson says.

These particles could also be used to evaluate the level of oxygen radicals in a patient’s tumor, which can reveal valuable information about how aggressive the tumor is.

“We think we may be able to reveal information about the tumor environment with these kinds of probes, if we can get them there,” Johnson says. “Someday you might be able to inject this in a patient and obtain real-time biochemical information about disease sites and also healthy tissues, which is not always straightforward.”

Steven Bottle, a professor of nanotechnology and molecular science at Queensland University of Technology, says the most impressive element of the study is the combination of two powerful imaging techniques into one nanomaterial.

“I believe this should deliver a very powerful, metabolically linked, multi-combination imaging modality which should provide a highly useful diagnostic tool with real potential to follow disease progression in vivo,” says Bottle, who was not involved in the study.

The research was funded by the National Institutes of Health, the Department of Defense, the National Science Foundation, and the Koch Institute for Integrative Cancer Research.


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. The original article was written by Anne Trafton. Note: Materials may be edited for content and length.


Journal Reference:

  1. Molly A. Sowers, Jessica R. McCombs, Ying Wang, Joseph T. Paletta, Stephen W. Morton, Erik C. Dreaden, Michael D. Boska, M. Francesca Ottaviani, Paula T. Hammond, Andrzej Rajca, Jeremiah A. Johnson. Redox-responsive branched-bottlebrush polymers for in vivo MRI and fluorescence imaging. Nature Communications, 2014; 5: 5460 DOI: 10.1038/ncomms6460
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