#Nanoscale biodegradable drug-delivery method could provide a year or more of steady doses About one in four older adults suffers from chronic pain.
Many of those people take medication usually as pills. But this is not an ideal way of treating pain:
Patients must take medicine frequently and can suffer side effects since the contents of pills spread through the bloodstream to the whole body.
Now researchers at MIT have refined a technique that could enable pain medication and other drugs to be released directly to specific parts of the bodynd in steady doses over a period of up to 14 months.
The method uses biodegradable nanoscale thin films laden with drug molecules that are absorbed into the body in an incremental process.
It's been hard to develop something that releases medication for more than a couple of months says Paula Hammond the David H. Koch Professor in Engineering at MIT
and a co-author of a new paper on the advance. Now we're looking at a way of creating an extremely thin film or coating that's very dense with a drug and yet releases at a constant rate for very long time periods.
and do anything about it says Bryan Hsu Phd'14 who helped develop the project as a doctoral student in Hammond's lab. You don't have to go recover it.
The paper was authored co by Hsu Myoung-Hwan Park of Shamyook University in South korea Samantha Hagerman'14 and Hammond
whose lab is in the Koch Institute for Integrative Cancer Research at MIT. The research project tackles a difficult problem in localized drug delivery:
Any biodegradable mechanism intended to release a drug over a long time period must be sturdy enough to limit hydrolysis a process by which the body's water breaks down the bonds in a drug molecule.
In this specific case the researchers used diclofenac a nonsteroidal anti-inflammatory drug that is often prescribed for osteoarthritis and other pain or inflammatory conditions.
The film can be applied onto degradable nanoparticles for injection into local sites or used to coat permanent devices such as orthopedic implants.
In tests the research team found that the diclofenac was released steadily over 14 months. Because the effectiveness of pain medication is evaluated subjective they the efficacy of the method by seeing how well the diclofenac blocked the activity of cyclooxygenase (COX) an enzyme central to inflammation in the body.
an illness such as tuberculosis for instance requires at least six months of drug therapy. It's not only viable for diclofenac Hsu says.
because it's broadly applicable to a lot of systems says Kathryn Uhrich a professor in the Department of chemistry
and Chemical Biology at Rutgers University adding that the research is really a nice piece of work.
The next steps for the researchers include studies to optimize these properties in different bodily environments and more tests perhaps with medications for both chronic pain and inflammation.
A major motivation for the work Hammond notes is the whole idea that we might be able to design something using these kinds of approaches that could create an easier lifestyle for people with chronic pain and inflammation.
and Park helped analyze the data a
#New material allows for ultra-thin solar cells Extremely thin, semitransparent, flexible solar cells could soon become reality.
At the Vienna University of Technology, Thomas Mueller, Marco Furchi and Andreas Pospischil have managed to create a semiconductor structure consisting of two ultra-thin layers,
which appears to be suited excellently for photovoltaic energy conversion Several months ago, the team had produced already an ultra-thin layer of the photoactive crystal tungsten diselenide.
Now, this semiconductor has successfully been combined with another layer made of molybdenum disulphide, creating a designer-material that may be used in future low-cost solar cells.
With this advance the researchers hope to establish a new kind of solar cell technology. Ultra-thin materials,
which consist only of one or a few atomic layers are currently a hot topic in materials science today.
Research on two-dimensional materials started with graphene, a material made of a single layer of carbon atoms.
Like other research groups all over the world, Thomas Mueller and his team acquired the necessary know-how to handle,
analyse and improve ultra-thin layers by working with graphene. This know-how has now been applied to other ultra-thin materials."
"Quite often, two-dimensional crystals have electronic properties that are completely different from those of thicker layers of the same material,
His team was the first to combine two different ultra-thin semiconductor layers and study their optoelectronic properties.
Tungsten diselenide is a semiconductor which consists of three atomic layers. One layer of tungsten is sandwiched between two layers of selenium atoms."
"We had already been able to show that tungsten diselenide can be used to turn light into electric energy
and vice versa",says Thomas Mueller. But a solar cell made only of tungsten diselenide would require countless tiny metal electrodes tightly spaced only a few micrometers apart.
If the material is combined with molybdenium disulphide, which also consists of three atomic layers, this problem is circumvented elegantly.
The heterostructure can now be used to build large-area solar cells. When light shines on a photoactive material single electrons are removed from their original position.
metallic electrodes can be used, through which the charge is sucked away -or a second material is added."
if the energies of the electrons in both layers are tuned exactly the right way. In the experiment, this can be done using electrostatic fields.
Florian Libisch and Professor Joachim Burgdörfer (TU Vienna) provided computer simulations to calculate how the energy of the electrons changes in both materials
and which voltage leads to an optimum yield of electrical power.""One of the greatest challenges was to stack the two materials,
the solar cell will not work.""Eventually, this feat was accomplished by heating both layers in vacuum and stacking it in ambient atmosphere.
and converted into electric energy. The material could be used for glass fronts, letting most of the light in,
but still creating electricity. As it only consists of a few atomic layers, it is extremely light weight (300 square meters weigh only one gram),
but increase the electrical power o
#Surprise discovery could see graphene used to improve health (Phys. org) chance discovery about the'wonder material'graphene already exciting scientists because of its potential uses in electronics,
energy storage and energy generation takes it a step closer to being used in medicine and human health.
Researchers from Monash University have discovered that graphene oxide sheets can change structure to become liquid crystal droplets spontaneously and without any specialist equipment.
With graphene droplets now easy to produce, researchers say this opens up possibilities for its use in drug delivery and disease detection.
The findings, published in the journal Chemcomm build on existing knowledge about graphene. One of the thinnest and strongest materials known to man,
graphene is a 2d sheet of carbon just one atom Thick with a'honeycomb'structure the'wonder material'is 100 times stronger than steel, highly conductive and flexible.
because graphene droplets change their structure in response to the presence of an external magnetic field,
because these particles can be toxic in certain physiological conditions, "Dr Majumder said.""In contrast, graphene doesn't contain any magnetic properties.
Under certain PH conditions they found that graphene behaves like a polymer-changing shape by itself.
potentially paving the way for new methods of disease detection as well.""Commonly used by jewelers,
the team used an advanced version of a polarised light microscope based at the Marine Biological Laboratory, USA,
"We used microscopes similar to the ones jewelers use to see the clarity of precious gems.
The only difference is the ones we used are much more precise due to a sophisticated system of hardware and software.
Dr Majumder and his team are working with graphite industry partner, Strategic Energy resources Ltd and an expert in polarized light imaging, Dr. Rudolf Oldenbourg from the Marine Biological Laboratory, USA,
to explore how this work can be translated and commercialised. Mr Mark Muzzin CEO of Strategic Energy resources Ltd said the collaboration with Monash was progressing well."
"We are pleased so to be associated with Dr Majumder's team at Monash University. The progress they have made with our joint project has been said astonishing,
"he. The research was made possible by an ARC Linkage grant awarded to Strategic Energy resources Ltd
and Monash University and was the first linkage grant for graphene research in Australia s
#Nanoscale details of electrochemical reactions in electric vehicle battery materials Using a new method to track the electrochemical reactions in a common electric vehicle battery material under operating conditions,
scientists at the U s. Department of energy's Brookhaven National Laboratory have revealed new insight into why fast charging inhibits this material's performance.
The study also provides the first direct experimental evidence to support a particular model of the electrochemical reaction.
The results, published August 4, 2014, in Nature Communications, could provide guidance to inform battery makers'efforts to optimize materials for faster-charging batteries with higher capacity."
"Our work was focused on developing a method to track structural and electrochemical changes at the nanoscale as the battery material was charging,
"said Brookhaven physicist Jun Wang, who led the research. Her group was interested particularly in chemically mapping
what happens in lithium iron phosphate-a material commonly used in the cathode, or positive electrode, of electrical vehicle batteries-as the battery charged."
"We wanted to catch and monitor the phase transformation that takes place in the cathode as lithium ions move from the cathode to the anode,
"she said. Getting as many lithium ions as possible to move from cathode to anode through this process,
known as delithiation, is the key to recharging the battery to its fullest capacity so it will be able to provide power for the longest possible period of time.
Understanding the subtle details of why that doesn't always happen could ultimately lead to ways to improve battery performance,
enabling electric vehicles to travel farther before needing to be recharged. Many previous methods used to analyze such battery materials have produced data that average out effects over the entire electrode.
These methods lack the spatial resolution needed for chemical mapping or nanoscale imaging, and are likely to overlook possible small-scale effects and local differences within the sample,
Wang explained. To improve upon those methods, the Brookhaven team used a combination of full-field, nanoscale-resolution transmission x-ray microscopy (TXM) and x-ray absorption near-edge spectroscopy (XANES) at the National Synchrotron Light source (NSLS),
a DOE Office of Science User Facility that provides beams of high-intensity x-rays for studies in many areas of science.
These x-rays can penetrate the material to produce both high-resolution images and spectroscopic data-a sort of electrochemical"fingerprint"that reveals,
pixel by pixel, where lithium ions remain in the material, where they've been removed leaving only iron phosphate,
and other potentially interesting electrochemical details. The scientists used these methods to analyze samples made up of multiple nanoscale particles in a real battery electrode under operating conditions (in operando.
But because there can be a lot of overlap of particles in these samples, they also conducted the same in operando study using smaller amounts of electrode material than would be found in a typical battery.
This allowed them to gain further insight into how the delithiation reaction proceeds within individual particles without overlap.
They studied each system (multi-particle and individual particles) under two different charging scenarios-rapid (like you'd get at an electric vehicle recharging station),
and slow (used when plugging in your vehicle at home overnight). These animated images of individual particles, taken
while the electrode is charging, show that lithiated (red) and delithiated (green) iron phosphate phases coexist within individual particles.
This finding directly supports a model in which the phase transformation proceeds from one phase to the other without the existence of an intermediate phase.
The detailed images and spectroscopic information reveal unprecedented insight into why fast charging reduces battery capacity.
the pixel-by-pixel images show that the transformation from lithiated to delithiated iron phosphate proceeds inhomogeneously.
That is, in some regions of the electrode all the lithium ions are removed leaving only iron phosphate behind,
and the electrode's capacity is well below the maximum level.""This is the first time anyone has been able to see that delithiation was happening differently at different spatial locations on an electrode under rapid charging conditions,
"Jun Wang said. Slower charging, in contrast, results in homogeneous delithiation, where lithium iron phosphate particles throughout the electrode gradually change over to pure iron phosphate
-and the electrode has a higher capacity. Scientists have known for a while that slow charging is better for this material,
"but people don't want to charge slowly, "said Jiajun Wang, the lead author of the paper."
and could give industry guidance to help them develop a future fast-charge/high-capacity battery,
For example, the phase transformation may happen more efficiently in some parts of the electrode than others due to inconsistencies in the physical structure or composition of the electrode-for example,
"So rather than focusing only on the battery materials'individual features, manufacturers might want to look at ways to prepare the electrode
so that all parts of it are the same, so all particles can be involved in the reaction instead of just some,
"These discoveries provide the fundamental basis for the development of improved battery materials, "said Jun Wang."
"In addition, this work demonstrates the unique capability of applying nanoscale imaging and spectroscopic techniques in understanding battery materials with a complex mechanism in real battery operational conditions."
"The paper notes that this in operando approach could be applied in other fields, such as studies of fuel cells and catalysts,
and in environmental and biological sciences. Future studies using these techniques at NSLS-II -which will produce x-rays 10,000 times brighter than those at NSLS-will have even greater resolution
#World's smallest propeller could be used for microscopic medicine If you thought that the most impressive news in shrinking technology these days was smart watches,
The impact of these miraculous microscopic machines on medicine can only be imagined, but there is no doubt that it will be significant.
mimicking the environment inside a living organism. The team is comprised of researchers from the Technion-Israel Institute of technology's Russell Berrie Nanotechnology Institute, the Max Planck Institute for Intelligent Systems,
and the Institute for Physical chemistry at the University of Stuttgart, Germany. The filament that makes up the propeller,
made of silica and nickel, is only 70 nm in diameter; the entire propeller is 400 nm long.
A nanometer is one billionth of a meter.""If you compare the diameter of the nanopropellers with a human blood cell,
then the propellers are 100 times smaller, "said Peer Fischer, a member of the research team
The hyaluronan gel contains a mesh of long proteins called polymers; the polymers are large enough to prevent micrometer-sized propellers from moving much at all.
But the openings are large enough for nanometer-sized objects to pass through. The scientists were able to control the motion of the propellers using a relatively weak rotating magnetic field.
The findings were somewhat surprising. The team expected that they would have trouble controlling the motion of the nanopropellers,
since at their size they start to be governed by diffusion, just as if they were molecules.
or negligible propulsion,"said study co-author Associate professor Alex Leshanksy of the Technion Faculty of Chemical engineering.
the real significance is how they might affect medicine.""One can now think about targeted applications,
#Existence of two-dimensional nanomaterial silicene questioned Sometimes scientific findings can shake the foundations of what was held once to be true causing us to step back
A recent study at the U s. Department of energy's Argonne National Laboratory has called into question the existence of silicene thought to be one of the world's newest and hottest two-dimensional nanomaterials.
The study may have great implications to a multi-billion dollar electronics industry that seeks to revolutionize technology at scales 80000 times smaller than the human hair.
Silicene was proposed as a two-dimensional sheet of silicon atoms that can be created experimentally by super-heating silicon
A metal semiconductor and insulator purified silicon is extremely stable and has become essential to the integrated circuits and transistors that run most of our computers.
Both silicene and silicon should react immediately with oxygen but they react slightly differently. In the case of silicon oxygen breaks some of the silicon bonds of the first one
or two atomic layers to form a layer of silicon-oxygen. This surprisingly acts a chemical barrier to prevent the decay of the lower layers.
Because it consists of only one layer of silicon atoms silicene must be handled in a vacuum.
Exposure to any amount of oxygen would completely destroy the sample. This difference is one of the keys to the researchers'discovery.
After depositing the atoms onto the silver platform initial tests identified that alloy-like surface phases would form until bulk silicon layers
which has been mistaken as two-dimensional silicene. Some of the bulk silicon platelets were more than one layer thick said Argonne scientist Nathan Guisinger of Argonne's Center for Nanoscale Materials.
We determined that if we were dealing with multiple layers of silicon atoms we could bring it out of our ultra-high vacuum chamber
Everybody assumed the sample would immediately decay as soon as they pulled it out of the chamber added Northwestern University graduate student Brian Kiraly one of the principal authors of the study.
Each new series of experiments presented a new set of clues that this was in fact not silicene.
We found out that what previous researchers identified as silicene is really just a combination of the silicon
and the silver said Northwestern graduate student Andrew Mannix. For their final test the researchers decided to probe the atomic signature of the material.
Materials are made up of systems of atoms that bond and vibrate in unique ways. Raman spectroscopy allows researchers to measure these bonds and vibrations.
Housed within the Center for Nanoscale Materials a DOE Office of Science User Facility the spectroscope allows researchers to use light to shift the position of one atom in a crystal lattice
which in turn causes a shift in the position of its neighbors. Scientists define a material by measuring how strong
or weak these bonds are in relation to the frequency at which the atoms vibrate. The researchers noticed something oddly familiar when looking at the vibrational signatures and frequencies of their sample.
Their sample did not exhibit characteristic vibrations of silicene but it did match those of silicon.
if you are trying to grow silicene. Explore further: Wonder material silicene has suicidal tendencie e
#Discovery is key to metal wear in sliding parts (w/Video) Researchers have discovered a previously unknown mechanism for wear in metals:
a swirling, fluid-like microscopic behavior in a solid piece of metal sliding over another.
The findings could be used to improve the durability of metal parts in numerous applications.""Wear is a major cause of failure in engineering applications,
"said Srinivasan Chandrasekar, a Purdue University professor of industrial engineering and materials engineering.""However, our findings have implications beyond wear itself,
"Using high-resolution imaging of sliding contacts in metals, we have demonstrated a new way by which wear particles and surface defects can form,
Narayan Sundaram, an assistant professor at the Indian Institute of Science; and Yang Guo, a research scientist at M4 Sciences.
and the sliding conditions did not generate enough heat to soften the metal. Yet, the swirling flow is more like behavior seen in fluids than in solids,
The team observed what happens when a wedge-shaped piece of steel slides over a flat piece of aluminum or copper.
The metals are used commonly to model the mechanical behavior of metals.""We speculated in the earlier paper that the swirly fluid-like surface flow discovered on sliding metal surfaces is likely to impact wear in sliding metal systems,
"he said.""Now we are confirming this speculation by direct observations
#Graphene and related materials promise cheap flexible printed cameras Dr Felice Torrisi University Lecturer in Graphene technology has been awarded a Young International Researchers'Fellowship from the National Science Foundation
of China to look at how graphene and two-dimensional materials could enable printed and flexible eyes.
or stamped on plastic or paper. For example it might eventually be embed possible to these printed flexible optoelectronic devices into clothes packaging wall papers posters touch screens or even buildings.
Everybody with a printer at home will be able to print their own artificial eye and physically stick it to a flexible mobile phone Felice said.
The goal of the 18 month project is to design develop and characterize inkjet printed 2d crystal-based flexible photodetectors and study their integration with commercial electronics.
Photodetectors are needed in cameras automotive applications sensing and telecommunications medical devices and security he says. If these could be made flexible they could be integrated in clothes rolled up
or printed over any irregular surface substantially increasing the quality of printed and flexible electronics.
The current generation of flexible photoactive materials based on organic polymers have a slow response time (few milliseconds)
which is too slow for photodetection. This represents a strong limitation for flexible electronics in a wide range of applications from active matrix displays to ultrafast light detectors and gas sensors.
Moreover organic polymers suffer from chemical instability at room conditions temperature and pressure) thus requiring extra protective layers
or special handling of the printed devices leading to an increase in cost. Graphene the ultimate thin membrane along with a wide range of two-dimensional (2d)- crystals (e g. hexagonal Boron nitride (h-BN) Molybdenum Disulfide (Mos2) and Tungsten Disulfide (WS2)) have changed radically the landscape
of science and technology with attractive physical properties for (opto) electronics sensing catalysis and energy storage. These 2d crystals can be exfoliated from layered compounds.
The layered compounds can be conductive semiconducting or insulating and their electronic properties depend on the number of layers.
For example graphene is highly conductive flexible and transparent and it is superior to conductive polymers in terms of cost stability and performance;
whereas Mos2 is optically active once reduced to a single 2d layer with a fast response time and excellent environmental stability.
In 2012 Drs Felice Torrisi Tawfique Hasan and Professor Andrea Ferrari at the Cambridge Graphene Centre invented a graphene ink
which conducts electricity and can be printed by a standard inkjet printer. The graphene-based ink enables cost-effective printed electronics on plastic.
Felice explains: Other conductive inks are made from precious metals such as silver which makes them very expensive to produce
and process whereas graphene is both cheap environmentally stable and does not require much processing after printing.
We used a simple sonication and centrifugation process to unveil graphene potential in inks and coating for printed electronicsover the last two years Dr Torrisi
and the team at the Cambridge Graphene Centre have been looking to formulate a set of inks based on various 2d crystals setting a new platform for printed electronics.
Felice says: This will create an entirely new set of tools for printable electronics with conductive semiconducting
and insulating properties with a faster response time outperforming the current organic semiconducting inks enabling printed flexible photodetectors
and possibly paving the way for printed flexible photo-cameras. When light impinges on a semiconducting 2d crystal (e g.
Mos2) due to their 2d nature electrons and holes are generated with a higher efficiency than the current photodetectors based on siliconthe project funded by the National Natural science Foundation of China looks into how to design printed flexible photodetectors
and environmental compatibility are key benefits to improving flexible optoelectronics Explore further: Formation of organic thin-film transistors through room-temperature printin n
#Cost-effective solvothermal synthesis of heteroatom (S or N)- doped graphene developed A research team led by group leader Yung-Eun Sung has announced that they have developed cost-effective technology to synthesize sulfur-doped and nitrogen-doped graphenes
which can be applied as high performance electrodes for secondary batteries and fuel cells. Yung-Eun Sung is both a group leader at the Center for Nanoparticle Research at Institute for Basic Science*(IBS) and a professor at the Seoul National University.
This achievement has great significance with regards to the development of relative simplicity, scalablity, and cost effectiveness processes that can produce heteroatom (S or N)- doped graphenes.
these materials enhance the performance of secondary batteries and drive down the cost of producing fuel cells.
This process using common laboratory reagent, sodium hydroxide (Naoh) and heteroatom-containing organic solvents as precursors.
In addition, the lithium-ion batteries that had applied modified graphenes to it, exhibited a higher capacity than the theoretical capacity of graphite
which was used previously in lithium-ion batteries. It presented high chemical stability which resulted in no capacity degradation in charge and discharge experiments.
The heteroatom-doped graphenes suggest the potential to be employed as an effective, alternative chemical material by demonstrating performance comparable to that of the expensive platinum catalyst used for the cathode of fuel cell batteries.
Platinum has a high profile because of its high chemical reactivity and electrocatalytic activity. However, limited resources and high expense have been stumbling blocks in its effective commercialization.
Group leader Yung-Eun Sung of the Center for Nanoparticle Research at IBS, says,"We expect that our synthetic approach will be developed to produce doped carbon materials based on other elements (e g.,
, florine, boron, phosphorus) which can then increase the method's potential applications in fuel cells lithium secondary batteries, sensors, and semiconductors
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