#Nanoparticles for clean drinking water One way of removing harmful nitrate from drinking water is to catalyse its conversion to nitrogen.
This process suffers from the drawback that it often produces ammonia. By using palladium nanoparticles as a catalyst,
and by carefully controlling their size, this drawback can be eliminated partially. It was research conducted by Yingnan Zhao of the University of Twente's MESA+Institute for Nanotechnology that led to this discovery.
Due to the excessive use of fertilizers, our groundwater is contaminated with nitrates, which pose a problem
if they enter the mains water supply. Levels have fallen significantly in recent years as a result of various European directives.
While this can be achieved through biological conversion (using bacteria to convert the nitrate to nitrogen gas),
Yingnan Zhao decided to use nanometre-sized colloidal palladium particles, as their dimensions can be controlled easily.
so stabilizers such as polyvinyl alcohol are added. Unfortunately, these stabilizers tend to shield the surface of the palladium particles,
which reduces their effectiveness as a catalyst. By introducing additional treatments, Yingnan Zhao has managed to fully expose the catalytic surface once again
This has resulted in palladium nanoparticles that can catalyse the conversion to nitrogen while producing very little ammonia.
which is entitled"Colloidal Nanoparticles as Catalysts and Catalyst Precursors for Nitrite Hydrogenation"on Thursday 15 january a
New nanotechnology keeps bacteria from sticking to surfaces Just as the invention of nonstick pans was a boon for chefs,
a new type of nanoscale surface that bacteria can't stick to holds promise for applications in the food processing, medical and even shipping industries.
The technology, developed collaboratively by researchers from Cornell University and Rensselaer Polytechnic institute, uses an electrochemical process called anodization to create nanoscale pores that change the electrical charge and surface energy of a metal surface,
and prevents attachment and biofilm formation. These pores can be as small as 15 nanometers;
a sheet of paper is about 100,000 nanometers thick. When the anodization process was applied to aluminum, it created a nanoporous surface called alumina,
which proved effective in preventing surrogates of two well-known pathogens, Escherichia coli o157: H7 and Listeria monocytogenes, from attaching,
according to a study recently published in the journal Biofouling. The study also investigates how the size of the nanopores changes the repulsive forces on bacteria."
"It's probably one of the lowest-cost possibilities to manufacture a nanostructure on a metallic surface,
"said Carmen Moraru, associate professor of food science and the paper's senior author. Guoping Feng, a research associate in Moraru's lab, is the paper's first author.
Finding low-cost solutions to limiting bacterial attachments is key, especially in biomedical and food processing applications."
"The food industry makes products with low profit margins, "said Moraru.""Unless a technology is affordable it doesn't stand the chance of being applied practically."
"Anodized metals could be used to prevent buildups of biofilms slick communities of bacteria that adhere to surfaces
and are tricky to remove in biomedical clean rooms and in equipment parts that are hard to reach or clean,
Moraru said. Anodized metal could also have marine applications, such as keeping ship hulls free of algae.
The collaborating group from Rensselaer Polytechnic institute is led by Diana Borca-Tasciuc, associate professor of mechanical, aerospace and nuclear engineering.
Explore further: New tech application keeps bacteria from sticking to surfaces Provided by Cornell University search and more info websit e
#Carbon nanotube finding could lead to flexible electronics with longer battery life University of Wisconsin-Madison materials engineers have made a significant leap toward creating higher-performance electronics with improved battery lifend the ability
to flex and stretch. Led by materials science Associate professor Michael Arnold and Professor Padma Gopalan, the team has reported the highest-performing carbon nanotube transistors ever demonstrated.
In addition to paving the way for improved consumer electronics, this technology could also have specific uses in industrial and military applications.
In a paper published recently in the journal ACS Nano, Arnold, Gopalan and their students reported transistors with an on-off ratio that's 1
000 times better and a conductance that's 100 times better than previous state-of-the-art carbon nanotube transistors."
"Carbon nanotubes are very strong and very flexible, so they could also be used to make flexible displays
and electronics that can stretch and bend, allowing you to integrate electronics into new places like clothing,
"says Arnold.""The advance enables new types of electronics that aren't possible with the more brittle materials manufacturers are currently using."
"Carbon nanotubes are single atomic sheets of carbon rolled up into a tube. As some of the best electrical conductors ever discovered, carbon nanotubes have long been recognized as a promising material for next-generation transistors,
which are semiconductor devices that can act like an on-off switch for current or amplify current. This forms the foundation of an electronic device.
However, researchers have struggled to isolate purely semiconducting carbon nanotubes, which are crucial, because metallic nanotube impurities act like copper wires and"short"the device.
Researchers have struggled also to control the placement and alignment of nanotubes. Until now these two challenges have limited the development of high-performance carbon nanotube transistors.
Building on more than two decades of carbon nanotube research in the field, the UW-Madison team drew on cutting-edge technologies that use polymers to selectively sort out the semiconducting nanotubes,
achieving a solution of ultra-high-purity semiconducting carbon nanotubes. Previous techniques to align the nanotubes resulted in less than-desirable packing density,
or how close the nanotubes are to one another when they are assembled in a film. However, the UW-Madison researchers pioneered a new technique,
called floating evaporative self-assembly, or FESA, which they described earlier in 2014 in the ACS journal Langmuir.
In that technique, researchers exploited a self-assembly phenomenon triggered by rapidly evaporating a carbon nanotube solution.
The team's most recent advance also brings the field closer to realizing carbon nanotube transistors as a feasible replacement for silicon transistors in computer chips and in high-frequency communication devices,
which are rapidly approaching their physical scaling and performance limits.""This is not an incremental improvement in performance,
"Arnold says.""With these results, we've really made a leap in carbon nanotube transistors. Our carbon nanotube transistors are an order of magnitude better in conductance than the best thin film transistor technologies currently being used commercially
while still switching on and off like a transistor is supposed to function.""The researchers have patented their technology through the Wisconsin Alumni Research Foundation
and have begun working with companies to accelerate the technology transfer to industry t
#A new step towards using graphene in electronic applications A team of the University of Berkeley
and the Centre for Materials Physics (CSIC-UPV/EHU) has managed with atomic precision to create nanostructures combining graphene ribbons of varying widths.
The work is being published in the prestigious journal Nature Nanotechnology. Few materials have received as much attention from the scientific world
or have raised so many hopes with a view to their potential deployment in new applications as graphene has.
This is largely due to its superlative properties: it is the thinnest material in existence almost transparent the strongest the stiffest and at the same time the most strechable the best thermal conductor the one with the highest intrinsic charge carrier mobility plus many more fascinating features.
Specifically its electronic properties can vary enormously through its confinement inside nanostructured systems for example. That is why ribbons or rows of graphene with nanometric widths are emerging as tremendously interesting electronic components.
On the other hand due to the great variability of electronic properties upon minimal changes in the structure of these nanoribbons exact control on an atomic level is an indispensable requirement to make the most of all their potential.
The lithographic techniques used in conventional nanotechnology do not yet have such resolution and precision. In the year 2010 however a way was found to synthesise nanoribbons with atomic precision by means of the so-called molecular self-assembly.
Molecules designed for this purpose are deposited onto a surface in such a way that they react with each other
and give rise to perfectly specified graphene nanoribbons by means of a highly reproducible process and without any other external mediation than heating to the required temperature.
In 2013 a team of scientists from the University of Berkeley and the Centre for Materials Physics (CFM) a mixed CSIC (Spanish National Research Council) and UPV/EHU (University of the Basque Country
) centre extended this very concept to new molecules that were forming wider graphene nanoribbons and therefore with new electronic properties This same group has managed now to go a step further by creating through this self-assembly heterostructures that blend segments of graphene nanoribbons of two different widths.
The forming of heterostructures with different materials has been a concept widely used in electronic engineering and has enabled huge advances to be made in conventional electronics.
We have managed now for the first time to form heterostructures of graphene nanoribbons modulating their width on a molecular level with atomic precision.
What is more their subsequent characterisation by means of scanning tunnelling microscopy and spectroscopy complemented with first principles theoretical calculations has shown that it gives rise to a system with very interesting electronic properties
which include for example the creation of what are known as quantum wells pointed out the scientist Dimas de Oteyza who has participated in this project.
This work the results of which are being published this very week in the prestigious journal Nature Nanotechnology
therefore constitutes a significant success towards the desired deployment of graphene in commercial electronic applications.
Dr Dimas G. de Oteyza who was previously at Berkeley and at the CFM is currently working at the Donostia International Physics Center (DIPC) as a Fellow Gipuzkoa.
The Fellows Gipuzkoa programme funded by the Chartered Provincial Council of Gipuzkoa is devoted in fact to bringing back young researchers with solid postdoctoral training in internationally prestigious groups and centres by offering them a platform for reincorporation through contracts with a duration
Manipulating nanoribbons at the molecular level More information: Bandgap Engineering of Bottom-up Synthesized Graphene nanoribbons by Controlled Heterojunctions.
Y.-C. Chen T. Cao C. Chen Z. Pedramrazi D. Haberer D. G. de Oteyza F. Fischer S. Loiue M
. F. Crommie Nature Nanotechnology (2015) DOI: 10.1038/nnano. 2014.307 7
#A speedy test for bladder cancer A fast and accurate urine test for bladder cancer developed by A*STAR researchers has the potential to replace the currently used invasive physical probe.
Cystoscopy clinical procedure that uses a narrow, tubular optical instrument called a cystoscope to view inside the bladders currently the gold standard for detecting cancer in this organ.
However, the technique is favored not by most patients because it is invasive, expensive and time consuming.
a recently discovered urinary antigen and a potential biomarker for bladder cancer. The new tool could be used as a high-throughput screening platform to identify patients at risk of developing the urologic condition.
The immunoassay employs two advanced technologies, namely surface-enhanced Raman scattering (SERS), a powerful spectroscopic technique for detecting analytes at low concentrations,
and bimetallic film over nanoparticles, a planar substrate for enhancing SERS signals. Together these technologies help to overcome interfering signals from the matrix background such as proteins in urine.
The bimetallic film over nanoparticles is coated also with osmium carbonyl clusters to which target-seeking antibodies can be conjugated for assaying A1at (see image).
The researchers first tested the immunoassay on a series of standard solutions containing A1at antigens at various concentrations in the range 10 to 1, 000 nanograms per milliliter.
They observed a'fingerprint'of A1at antigens spectral change in the 1, 850 to 2, 130 cm#1 region that increases with concentration.
The scientists then tried the immunoassay on urine samples from nine patients. They found significantly elevated levels of A1at in bladder cancer patients.
There was also a marked difference in the A1at concentrations of cancer and non-cancer patients,
which suggests that the technique is highly discriminative, specific and accurate. Importantly, only tiny amounts of sample were required:
the SERS-based bioassay has two practical advantages: the low-volume sample requires no purification prior to testing
"We have developed a smart SERS biosensor for the rapid screening of bladder cancer, "says Olivo."
the osmium carbonyl clusters can be swapped with other metal carbonyl species to account for different needs and purposes. p
#Researchers find exposure to nanoparticles may threaten heart health Nanoparticles extremely tiny particles measured in billionths of a meter are increasingly everywhere and especially in biomedical products.
Their toxicity has been researched in general terms but now a team of Israeli scientists has for the first time found that exposure nanoparticles (NPS) of silicon dioxide (Sio2) can play a major role in the development of cardiovascular diseases
when the NP cross tissue and cellular barriers and also find their way into the circulatory system.
Their study is published in the December 2014 issue of Environmental Toxicology. The research team was comprised of scientists from the Technion Rappaport Faculty of medicine Rambam Medical center
and the Center of Excellence in Exposure Science and Environmental Health (TCEEH Environmental exposure to nanoparticles is becoming unavoidable due to the rapid expansion of nanotechnology says the study's lead author Prof.
Michael Aviram of the Technion Faculty of medicine This exposure may be especially chronic for those employed in research laboratories
and in high tech industry where workers handle manufacture use and dispose of nanoparticles. Products that use silica-based nanoparticles for biomedical uses such as various chips drug or gene delivery and tracking imaging ultrasound therapy and diagnostics may also pose an increased cardiovascular
risk for consumers as well. In this study researchers exposed cultured laboratory mouse cells resembling the arterial wall cells to NPS of silicon dioxide
and investigated the effects. Sio2 NPS are toxic to and have significant adverse effects on macrophages a type of white blood cell that take up lipids leading to atherosclerotic lesion development and its consequent cardiovascular events such as heart attack or stroke.
Macrophages accumulation in the arterial wall under atherogenic conditions such as high cholesterol triglycerides oxidative stress#are converted into lipids or laden foam cells
which in turn accelerate atherosclerosis development. Macrophage foam cells accumulation in the arterial wall are a key cell type in the development of atherosclerosis
which is an inflammatory disease says co-author Dr. Lauren Petrick. The aims of our study were to gain additional insight into the cardiovascular risk associated with silicon dioxide nanoparticle exposure
and discover the mechanisms behind Si02's induced atherogenic effects on macrophages. We also wanted to use nanoparticles as a model for ultrafine particle (UFP) exposure as cardiovascular disease risk factors.
Both NPS and UFPS can be inhaled and induce negative biological effects. However until this study their effect on the development of atherosclerosis has been largely unknown.
Here researchers have discovered for the first time that the toxicity of silicon dioxide nanoparticles has a significant and substantial effect on the accumulation of triglycerides in the macrophages at all exposure concentrations analyzed
and that they also increase oxidative stress and toxicity. A recent update from the American Heart Association also suggested that fine particles in air pollution leads to elevated risk for cardiovascular diseases.
However more research was needed to examine the role of ultrafine particles (which are much smaller than fine particles) on atherosclerosis development and cardiovascular risk.
The number of nano-based consumer products has risen a thousand fold in recent years with an estimated world market of $3 trillion by the year 2020 conclude the researchers.
This reality leads to increased human exposure and interaction of silica-based nanoparticles with biological systems.
Because our research demonstrates a clear cardiovascular health risk associated with this trend steps need to be taken to help ensure that potential health
and environmental hazards are being addressed at the same time as the nanotechnology is being developed. Explore further: New driver of atherosclerosis offers potential as therapeutic targe r
#Researchers create novel nanobowl optical concentrator for organic solar cell Geometrical light trapping is a simple and promising strategy to largely improve the optical absorption and efficiency of solar cells.
Nonetheless implementation of geometrical light trapping in organic photovoltaic (OPV) is challenging due to the fact that uniform organic active layer can rarely be achieved on textured substrate.
Professor Zhiyong Fan and his group from Hong kong University of Science and Technology (HKUST) reported novel nanobowl optical concentrator fabricated on low-cost aluminum foil
and aiming at tackling this problem. They have fabricated successfully OPV devices based on such optical concentrator
and demonstrated over 28%enhancement in power conversion efficiency over the devices without nanobowl. This work was published in Science Bulletin.
Solar energy is one of the most promising renewable energy resources and represents a clean and ultimate replacement for fossil fuels in the future.
Over the past decades enormous efforts have been invested in developing efficient and cost effective photovoltaic devices
and using indium-doped tin oxide as electrode. However such substrate is not flexible and the relatively high resistance of ITO electrode will compromises the OPV device performance.
Comparatively an aluminum foil substrate has the advantages of excellent conductivity flexibility cost-effectiveness and roll-to-roll processibility.
Meanwhile light trapping by nano-textured substrate is an appealing strategy to improve solar cell efficiency.
The novel nanobowl optical concentrator developed by Professor Zhiyong Fan can largely enhance the optical absorption in the active layer of organic solar cell
In addition they have investigated the effect of geometry of nanobowl on the solar cell performance and three types of nanobowl with pitch of 1000 nm 1200 nm and 1500 nm were studied.
Solar cells based on nanobowl with pitch of 1000 nm exhibited the best photon absorption in photoactive layer leading to the highest short-circuit current density of 9. 41 ma cm-2 among all nanobowl substrates.
With open-circuit voltage of 0. 573 V and fill factor of 57.9%this nanobowl solar cell achieved a solar energy conversion efficiency of 3. 12
This work not only revealed the in depth understanding of light trapping by nanobowl optical concentrator but also demonstrated the feasibility of implementing geometrical light trapping in low-cost solution processible OPV.
The development of the novel nanobowl optical concentrator and its application on OPV were a collaborative effort involving Professors in Department of chemistry of HKUST including Professor Shihe Yang
and Professor He (Henry) Yan who are working on cutting-edge researches about organic photovoltaics. The research project was supported by General Research Funds from Hong kong Research Grants Council and Hong kong Innovation Technology Commission.
Imec demonstrates organic photovoltaics modules showing excellent optical properties high efficiencies More information: Nanobowl optical concentrator for efficient light trapping and high-performance organic photovoltaics.
Science Bulletin. DOI: 10.1007/s11434-014-0693
#Carbon nanoballs can greatly contribute to sustainable energy supply Researchers at Chalmers University of Technology have discovered that the insulation plastic used in high-voltage cables can withstand a 26 per cent higher voltage
if nanometer-sized carbon balls are added. This could result in enormous efficiency gains in the power grids of the future,
which are needed to achieve a sustainable energy system. The renewable energy sources of tomorrow will often be found far away from the end user.
Wind turbines, for example, are most effective when placed out at sea. Solar energy will have the greatest impact on the European energy system
if focus is on transport of solar power from North africa and Southern Europe to Northern europe.""Reducing energy losses during electric power transmission is one of the most important factors for the energy systems of the future,
"says Chalmers researcher Christian Müller.""The other two are development of renewable energy sources and technologies for energy storage."
"Together with colleagues from Chalmers University of Technology and the company Borealis in Sweden, he has found a powerful method for reducing energy losses in alternating current cables.
The results were published recently in Advanced Materials. The researchers have shown that different variants of the C60 carbon ball,
a nanomaterial in the fullerene molecular group, provide strong protection against breakdown of the insulation plastic used in high-voltage cables.
It is sufficient to add very small amounts of fullerene to the insulation plastic for it to withstand a voltage that is 26 per cent higher, without the material breaking down,
than the voltage that plastic without the additive can withstand. Carbon nanoballs can greatly contribute to sustainable energy supply An electrical tree,
which is a major electrical breakdown mechanism of insulation plastic. Fullerenes prevent electrical trees from forming by capturing electrons that would
otherwise destroy chemical bonds in the plastic. Credit: Anette Johansson and Markus Jarvid"Being able to increase the voltage to this extent would result in enormous efficiency gains in power transmission all over the world,
"says Christian Müller.""A major issue in the industry is how transmission efficiency can be improved without making the power cables thicker,
"Using additives to protect the insulation plastic has been known a concept since the 1970s, but until now it has been unknown exactly
In recent years, other researchers have experimented with fullerenes in the electrically conductive parts of high-voltage cables.
Carbon nanoballs can greatly contribute to sustainable energy supply Wind turbines are most effective when placed out at sea.
Lina Bertling The Chalmers researchers have demonstrated now that fullerenes are the best voltage stabilizers identified for insulation plastic thus far.
the researchers tested a number of molecules that are used also within organic solar cell research at Chalmers.
and were added to pieces of insulation plastic used for high-voltage cables. The pieces of plastic were subjected then to an increasing electric field until they crackled.
Fullerenes turned out to be the type of additive that most effectively protects the insulation plastic.
The next step involves testing the method on a large scale in complete high-voltage cables for alternating current.
The researchers will also test the method in high-voltage cables for direct current, since direct current is more efficient than alternating current for power transmission over very long distances c
#Arming nanoparticles for cancer diagnosis and treatment UCD researchers have manipulated successfully nanoparticles to target two human breast cancer cell lines as a tool in cancer diagnosis and treatment.
Coating nanoparticles with different substances allows their interaction with cells to be tuned in a particular way.
For example using an optically active particle like gold (Au) will provide excellent contrast in near infrared (NIR) imaging
and if heated can actually destroy the surrounding tissue. This is called photothermal ablation therapy. Magnetically active particles like iron (Fe) can enable physical therapies by generating heat
when exposed to alternating magnetic fields causing cell death (magnetic hyperthermia). The UCD team led by Conway Fellows Professor Gil Lee in the School of Chemistry
and Chemical Biology and Professor Walter Kolch in Systems Biology Ireland synthesised nanorods with a long iron segment coated with polyethylene glycol
and a short gold tip coated with single layer of the protein heregulin (HRG). HRG is a growth factor that binds to
and activates the Erbb family of protein receptors. Erbb2 is overexpressed in certain breast cancers and linked with poor prognosis.
The team believe that Fe-Au functionalised nanorods used in conjunction with these drugs could be useful in cancer treatment.
After characterising and tuning the interaction of the nanorods with the cells the research team assessed how the cells respond to mechanical stimulation.
and used a novel microfluidic chip to monitor the interaction of individual nanorods with two human breast cancer cell lines that express the Erbb family of receptors at different rates.
When the HRG-nanorods bind to cancer cells expressing Erbb they kick off a cascade of signalling events that lead to cell death.
Using magnetic tweezers to stretch cells we were able to further activate cell signalling pathways to trigger cell death.
This was even more effective in causing cancer cell death than magnetic hyperthermia the other therapeutic approach we assessed explained Dr Devrim Kilinc first author and research fellow in the Lee group.
The results are a positive indication for nanoscale targeting and localised manipulation of cancer cells with a specific receptor profile.
#Stacking two-dimensional materials may lower cost of semiconductor devices A team of researchers led by North carolina State university has found that stacking materials that are only one atom thick can create semiconductor junctions that transfer charge efficiently regardless of
whether the crystalline structure of the materials is mismatched-lowering the manufacturing cost for a wide variety of semiconductor devices such as solar cells lasers and LEDS.
This work demonstrates that by stacking multiple two-dimensional (2-D) materials in random ways we can create semiconductor junctions that are as functional as those with perfect alignment says Dr. Linyou Cao senior author of a paper on the work
and an assistant professor of materials science and engineering at NC State. This could make the manufacture of semiconductor devices an order of magnitude less expensive.
For most semiconductor electronic or photonic devices to work they need to have a junction
which is where two semiconductor materials are bound together. For example in photonic devices like solar cells lasers and LEDS the junction is where photons are converted into electrons or vice versa.
All semiconductor junctions rely on efficient charge transfer between materials to ensure that current flows smoothly
and that a minimum of energy is lost during the transfer. To do that in conventional semiconductor junctions the crystalline structures of both materials need to match.
However that limits the materials that can be used because you need to make sure the crystalline structures are compatible.
And that limited number of material matches restricts the complexity and range of possible functions for semiconductor junctions.
But we found that the crystalline structure doesn't matter if you use atomically thin 2-D materials Cao says.
We used molybdenum sulfide and tungsten sulfide for this experiment but this is a fundamental discovery that we think applies to any 2-D semiconductor material.
or more semiconductor materials and you can stack them randomly but still get efficient charge transfer between the materials.
Currently creating semiconductor junctions means perfectly matching crystalline structures between materials -which requires expensive equipment sophisticated processing methods and user expertise.
This manufacturing cost is a major reason why semiconductor devices such as solar cells lasers and LEDS remain very expensive.
But stacking 2-D materials doesn't require the crystalline structures to match. It's as simple as stacking pieces of paper on top of each other-it doesn't even matter
if the edges of the paper line up Cao says. The paper Equally Efficient Interlayer Exciton Relaxation and Improved Absorption in Epitaxial and Non-epitaxial Mos2/WS2 Heterostructures was published as a just-accepted manuscript in Nano Letters Dec 3.
Researchers capture microimages of micropillar P/N junctions on a semiconductor More information: Nano Letters pubs. acs. org/doi/abs/10.1021/nl503817 7
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