#Novel nanoparticle therapy promotes wound healing (w/video)( Nanowerk News) An experimental therapy developed by researchers at Albert Einstein College of Medicine of Yeshiva University cut in half the time it takes to heal
wounds compared to no treatment at all. Details of the therapy, which was tested successfully in mice,
were published online in the Journal of Investigative Dermatology("Fidgetin-like 2: a novel microtubule-based regulator of wound healing".
"e envision that our nanoparticle therapy could be used to speed the healing of all sorts of wounds,
including everyday cuts and burns, surgical incisions, and chronic skin ulcers, which are a particular problem in the elderly
and people with diabetes, said study co-leader David J. Sharp, Ph d.,professor of physiology & biophysics at Einstein.
Dr. Sharp and his colleagues had discovered earlier that an enzyme called fidgetin-like 2 (FL2) puts the brakes on skin cells as they migrate towards wounds to heal them.
They reasoned that the healing cells could reach their destination faster if their levels of FL2 could be reduced.
So they developed a drug that inactivates the gene that makes FL2 and then put the drug in tiny gel capsules called nanoparticles
and applied the nanoparticles to wounds on mice. The treated wounds healed much faster than untreated wounds.
FL2 belongs to the fidgetin family of enzymes, which play varying roles in cellular development and function.
To learn more about FL2 role in humans, Dr. Sharp suppressed FL2 activity in human cells in tissue culture.
When those cells were placed on a standard wound assay (for measuring properties like cell migration and proliferation),
they moved unusually fast. his suggested that if we could find a way to target FL2 in humans,
we might have a new way to promote wound healing, said Dr. Sharp. Dr. Sharp and project co-leader Joshua Nosanchuk, M d.,professor of medicine at Einstein and attending physician, infectious diseases at Montefiore Medical center, developed a wound-healing therapy that uses
molecules of silencing RNA (sirnas) specific for FL2. The sirnas act to silence genes. They do so by binding to a gene MESSENGER RNA (mrna),
preventing the mrna from being translated into proteins (in this case, the enzyme FL2). However, irnas on their own won be effectively taken up by cells,
particularly inside a living organismsaid Dr. Sharp. hey will be degraded quickly unless they are put into some kind of delivery vehicle.
To find a way to deliver sirnas for curbing FL2, Dr. Sharp collaborated with Joel Friedman, M d.,Ph d.,professor of physiology & biophysics and of medicine at Einstein,
and study co-leader Adam Friedman, M d.,director of dermatologic research at Einstein and Montefiore, who together had developed nanoparticles that protect molecules such as sirna from being degraded as they ferry the molecules to their intended targets.
The nanoparticles with their sirna cargoes were tested then by topically applying them to mice with either skin excisions or burns.
In both cases, the wounds closed more than twice as fast as in untreated controls. ot only did the cells move into the wounds faster,
but they knew what to do when they got there, said Dr. Sharp. e saw normal,
Dr. Sharp plans to start testing the therapy on pigs, whose skin closely resembles that of humans, within months a
The material's greatest asset--its monolayer thickness--is also its biggest challenge. Monolayer Mos2's ultra-thin structure is strong, lightweight,
and flexible, making it a good candidate for many applications, such as high-performance, flexible electronics. Such a thin semiconducting material,
however, has very little interaction with light, limiting the material's use in light emitting and absorbing applications."
"The problem with these materials is that they are just one monolayer thick, "said Koray Aydin, assistant professor of electrical engineering and computer science at Northwestern University's Mccormick School of engineering."
"So the amount of material that is available for light emission or light absorption is limited very. In order to use these materials for practical photonic and optoelectric applications,
"Aydin and his team tackled this problem by combining nanotechnology, materials science, and plasmonics, the study of the interactions between light and metal.
and fabricated a series of silver nanodiscs and arranged them in a periodic fashion on top of a sheet of Mos2.
Not only did they find that the nanodiscs enhanced light emission, but they determined the specific diameter of the most successful disc,
which is 130 nanometers. Silver nanodiscs on monolayer molybdenum disulfide.""We have known that these plasmonic nanostructures have the ability to attract
and trap light in a small volume, "said Serkan Butun, a postdoctoral researcher in Aydin's lab."Now we've shown that placing silver nanodiscs over the material results in twelve times more light emission."
"The use of the nanostructures--as opposed to using a continuous film to cover the Mos2--allows the material to retain its flexible nature and natural mechanical properties.
Supported by Northwestern's Materials Research Science and Engineering Center and the Institute for Sustainability and Energy at Northwestern,
the research is described in the March 2015 online issue of Nano Letters("Enhanced Light Emission from Large-Area Monolayer Mos2 Using Plasmonic Nanodisc Arrays").
"Butun is first author of the paper. Sefaatiin Tongay, assistant professor of materials science and engineering at Arizona State university, provided the large-area monolayer Mos2 material used in the study.
With enhanced light emission properties, Mos2 could be a good candidate for light emitting diode technologies.
The team's next step is to use the same strategy for increasing the material's light absorption abilities to create a better material for solar cells and photodetectors."
"This is a huge step, but it's not the end of the story, "Aydin said."
"There might be ways to enhance light emission even further. But, so far, we have shown successfully that it's indeed possible to increase light emission from a very thin material
#Next important step toward quantum computer with quantum dots Physicists at the Universities of Bonn and Cambridge have succeeded in linking two completely different quantum systems to one another.
The results have now been published in Physical Review Letters("Direct Photonic Coupling of a Semiconductor Quantum dot and a Trapped Ion".
There the so-called quantum dots (abbreviated: qdots) play the role of the forgetful genius. Quantum dots are unbeatably fast,
when it comes to disseminating quantum information. Unfortunately, they forget the result of the calculation
Experts speak of a hybrid system, because it combines two completely different quantum systems with one another. Absentminded qdots qdots are considered the great hopes in the development of quantum computers.
In principle, they are miniaturized extremely electron storage units. qdots can be produced using the same techniques as normal computer chips.
it is only necessary to miniaturize the structures on the chips until they hold just one single electron (in a conventional PC it is 10 to 100 electrons.
This decay produces a small flash of light: a photon. Photons are wave packets that vibrate in a specific plane the direction of polarization.
Dr. Michael Khl from the Institute of Physics at the University of Bonn.""Then we stored the direction of polarization of the photon".
They transported the photon via the fiber to the ion many meters away. The fiberoptic networks used in telecommunications operate very similarly.
To make the transfer of information as efficient as possible, they had trapped the ion between two mirrors.
In the long term, researchers around the world are hoping for true marvels from this new type of computer:
such as the factoring of large numbers, should be child's play for such a computer. In contrast, conventional computers find this a really tough nut to crack.
However, a quantum computer displays its talents only for such special tasks: For normal types of basic computations, it is pitifully slow w
#High-tech method allows rapid imaging of functions in living brain Researchers studying cancer and other invasive diseases rely on high-resolution imaging to see tumors and other activity deep within the body's tissues.
Using a new high-speed, high-resolution imaging method, Lihong Wang, Phd, and his team at Washington University in St louis were able to see blood flow, blood oxygenation, oxygen metabolism and other functions inside a living mouse brain at faster rates than ever before.
Using photoacoustic microscopy (PAM), a single wavelength, pulse-width-based technique developed in his lab, Wang,
the Gene K. Beare Professor of Biomedical engineering in the School of engineering & Applied science, was able to take images of blood oxygenation 50 times faster than their previous results using fast-scanning PAM;
100 times faster than their acoustic-resolution system; and more than 500 times faster than phosphorescence-lifetime-based two-photon microscopy (TPM.
The results are published March 30 in Nature Methods advanced online publication("High-speed label-free functional photoacoustic microscopy of mouse brain in action".
"Other existing methods, including functional MRI (fmri), TPM and wide-field optical microscopy, have provided information about the structure, blood oxygenation and flow dynamics of the mouse brain.
However, those methods have speed and resolution limits, Wang says. To make up for these limitations, Wang and his lab implemented fast-functional PAM,
which allowed them to get high-resolution, high-speed images of a living mouse brain through an intact skull.
and more than 35 times finer than ultrasound-array-based photoacoustic computed tomography. Most importantly, PAM allowed 3-D blood oxygenation imaging with capillary-level resolution at a one-dimensional imaging rate of 100 khz, or 10 microseconds."
"In addition, we were able to map the mouse brain oxygenation vessel by vessel using this method.""
Phd, program director for Optical Imaging at the National Institute of Biomedical Imaging and Bioengineering."
"Wang's work dramatically increases both the spatial and temporal resolution of photoacoustic imaging, which now has the potential to reveal blood flow dynamics and oxygen metabolism at the level of individual cells.
In the future, photoacoustic imaging could serve as an important complement to fmri, leading to critical insights into brain function and disease development."
Given the importance of oxygen metabolism in basic biology and diseases such as diabetes and cancer,
#A quantum sensor for nanoscale electron transport The word defect doesnt usually have a good connotation--often indicating failure.
But for physicists, one common defect known as a nitrogen-vacancy center (NV center) has applications in both quantum information processing and ultra-sensitive magnetometry, the measurement of exceedingly faint magnetic fields.
In an experiment, recently published in Science("Probing Johnson noise and ballistic transport in normal metals with a single-spin qubit),
"JQI Fellow Vladimir Manucharyan and colleagues at Harvard university used NV centers in diamond to sense the properties of magnetic field noise tens of nanometers away from the silver samples.
Graphic depiction of NV center sensors (red glowing spheres) used to probe electron motion in a conductor.
JQI) Diamond, which is a vast array of carbon atoms, can contain a wide variety of defects.
atomlike energy levels that can be probed using green laser light. Like atomic systems, the NV centers can be used as a qubit.
A conductive silver sample is deposited onto a diamond substrate that contains NV centers. While these defects can occur naturally
the team here purposefully creates them approximately 15 nanometers away from the silver layer. At temperatures above absolute zero, the electrons inside of the silver layer (or any conductor) bounce around
Since electrons are charged particles, their motion results in fluctuating magnetic fields, which extend outside of the conductor.
Typically, changing magnetic fields can wreak all sorts of havoc, including for the nearby NV centers.
Here, each NV center is used as a sensor that can be thought of as switching between two states
1 and 0. The sensor can be calibrated in the presence of a constant magnetic field such that it is in state 1
. If the sensor experiences an oscillating magnetic field, the sensor switches to state 0. There is one more important component to this sensor--it can detect magnetic field strength as well.
For weak magnetic field fluctuations, the NV sensor will slowly decay to state 0; for stronger fluctuations, it will decay much faster from 1 to 0. By detecting different decay times,
physicists can precisely measure the fluctuating magnetic fields, which tells them about the electron behavior at a very small length scale.
Like any good sensor, the NV centers are almost completely non-invasivetheir read-out with laser light does not disturb the sample they are sensing.
The team studied the scaling of the magnetic noise with different parameters such as temperature and distance from the silver surface and found excellent agreement with theoretical predictions.
In addition, by changing the nature of the silver sample from polycrystalline to single-crystalline they were able to observe a dramatic difference in the behavioral trends of the magnetic field noise
thus electrons travel dont travel very far--roughly 10 nanometers or less--before scattering off an obstacle.
In contrast, a single crystal is uniform at these length scales and electrons can travel over 100 times farther.
and corresponding magnetic field noise from the single silver crystal is a departure from so-called Ohmic predictions of the polycrystalline case,
These results demonstrate that single NV centers can be used to directly study electron behavior inside of a conductive material on the nanometer length scale.
as well as metrology for commercial materials science e
#Extremely sensitive temperature sensor developed with plant nanobionic materials Humans have been inspired by nature since the beginning of time.
We mimic nature to develop new technologies, with examples ranging from machinery to pharmaceuticals to new materials.
in order to develop an extremely sensitive temperature sensor they took a close look at temperature-sensitive plants. However, they did not mimic the properties of the plants;
"explains Chiara Daraio, Professor of Mechanics and Materials. The scientists were able to develop by far the most sensitive temperature sensor:
an electronic module that changes its conductivity as a function of temperature.""No other sensor can respond to such small temperature fluctuations with such large changes in conductivity.
Our sensor reacts with a responsivity at least 100 times higher compared to the best existing sensors,
"says Raffaele Di Giacomo, a post-doc in Daraio's group. Water is replaced by nanotubes It has been known for decades that plants have the extraordinary ability to register extremely fine temperature differences
and respond to them through changes in the conductivity of their cells. In doing so, plants are better than any man-made sensor so far.
Di Giacomo experimented with tobacco cells in a cell culture.""We asked ourselves how we might transfer these cells into a lifeless,
These electrically conductive carbon nanotubes formed a network between the tobacco cells and were also able to penetrate the cell walls.
When Di Giacomo dried the nanotube-cultivated cells, he discovered a woody, firm material that he calls'cyberwood'.
'In contrast to wood, this material is electrically conductive thanks to the nanotubes, and interestingly the conductivity is temperature-dependent and extremely sensitive,
Touchless touchscreen and heat-sensitive cameras As demonstrated by experiments, the cyberwood sensor can identify warm bodies even at distance;
for example, a hand approaching the sensor from a distance of a few dozen centimetres. The sensor's conductivity depends directly on the hand's distance from the sensor.
According to the scientists, cyberwood could be used in a wide range of applications; for instance, in the development of a'touchless touchscreen'that reacts to gestures,
with the gestures recorded by multiple sensors. Equally conceivable might be heat-sensitive cameras or night-vision devices.
Thickening agent pectin in a starring role The ETH scientists, together with a collaborator at the University of Salerno, Italy,
not only subjected their new material's properties to a detailed examination, they also analysed the origins of their extraordinary behaviour.
They discovered that pectins and charged atoms (ions) play a key role in the temperature sensitivity of both living plant cells and the dry cyberwood.
As a result, the material conducts electricity better when temperature increases. The scientists submitted a patent application for their sensor.
In ongoing work, they are now further developing it such that it functions without plant cells, essentially with only pectin and ions.
Their goal is to create a flexible, transparent and even biocompatible sensor with the same ultrahigh temperature sensitivity.
Such a sensor could be moulded into arbitrary shapes and produced at extremely low cost. This will open the door to new applications for thermal sensors in biomedical devices
consumer products and low cost thermal cameras s
#Soft, energy-efficient robotic wings Dielectric elastomers are novel materials for making actuators or motors with soft and lightweight properties that can undergo large active deformations with high-energy conversion efficiencies.
This has made dielectric elastomers popular for creating devices such as robotic hands, soft robots, tunable lenses and pneumatic valves--and possibly flapping robotic wings.
Reporting this week in the journal Applied Physics Letters("Phenomena of nonlinear oscillation and special resonance of a dielectric elastomer minimum energy structure rotary joint"),researchers from the Harbin Institute of technology in Weihai, China
and the University of California Los angeles (UCLA), have discovered a new resonance phenomenon in a dielectric elastomer rotary joint that can make the artificial joint bend up and down,
like a flapping wing. These images show:(Left) The structure of the rotary joint. Right) The system to measure the joint rotation.
Jianwen Zhao/Harbin Institute of technology in Weihai, University of California-Los angeles)" The dielectric elastomer is a kind of electro-active polymer that can deform
if you apply a voltage on it, "said Jianwen Zhao, an associate professor of the Department of Mechanical engineering at the Harbin Institute of technology.
He said that most studies on dielectric elastomers are using a static or stable voltage to stimulate the joint motion,
which makes the joint bend at a fixed angle, while they are interested in seeing how the artificial joint react to an alternating or periodically changing voltage."
"We found that alternating voltages can make the joint continuously bend at different angles. Especially, when the rotational inertia of the joint or the applied voltage is large enough,
the joint can deform to negative angles, in other words, it can bend beyond 90 degrees to 180 degrees,
"Zhao said this new phenomenon makes the dielectric elastomer joint a good candidate for creating a soft and lightweight flapping wing for robotic birds,
which would be more efficient than bird wings based on electrical motors due to the higher energy conversion efficiency (60 to 90 percent) of the dielectric elastomer.
Dielectric elastomers, due to their soft and lightweight inherent properties and superior electromechanical performances, are considered as a kind of material close to human muscles
Made by sandwiching a soft insulating elastomer film between two compliant electrodes, dielectric elastomers can be squeezed
and expanded in a plane when a voltage is applied between electrodes. In contrast to actuators based on rigid materials such as silicon, dielectric elastomers can reach a very large extent of stretch, often exceeding 100 percent elongation while not breaking,
enabling new possibilities in many fields including soft robotics, tunable optics, and cell manipulation. The dielectric elastomer actuator Zhao used is called a"dielectric elastomer minimum-energy structure"
which is composed of a thin elastic frame and pre-stretched dielectric elastomer films, Zhao said. After adhering the pre-stretched film to the thin elastic frame,
the restoring force of the dielectric elastomer film bends the elastic frame, balancing at a minimum energy state.
When applying kilovolts of low-current electricity on the dielectric elastomer, the frame flattens out and the bending angle decreases.
To restrict frame bending to only one axis, two stiffening frames are mounted to the primary frame as rigid nonbending edges,
the whole thing then forms a rotary joint. Dynamically changing the voltage can dynamically change the joint angle
which makes dielectric elastomer minimum-energy structures a useful structure for fabricating soft devices, Zhao said.
A New Oscillation Phenomenon Found In Zhao's experiment, the researchers stimulated the motion of the rotary joint using an alternating, square-wave voltage,
After experimenting with various parameters such as voltage values, frequencies and the joint mass in the dielectric elastomer joint system,
indicating a larger lift force in the special resonance. This new phenomenon and the principle, Zhao noted, may open doors for many novel soft devices,
such as soft and lightweight robots for circumstances with restricted space and weight requirements or flapping wings of soft robotic birds that can generate a large lift force.
Also, since dielectric elastomers feature high energy density (seventy times higher than conventional electromagnetic actuators) and high-energy conversion efficiency (60 to 90 percent), they could be good candidates for making energy-efficient devices,
The researchers'next step is to improve the function of the dielectric elastomer rotary joint and refine the fabrication technique to make a real flapping wing g
#Thermal properties of nanowires-Follow the heat A mathematical model of heat flow through miniature wires could help develop thermoelectric devices that efficiently convert heat even their own waste heat into electricity.
which are responsible for carrying heat in insulating materials. Phonons typically move in straight lines in nanowires threads barely a few atoms wide.
Previous calculations suggested that if parts of a nanowire contained random arrangements of two different types of atoms,
phonons would be stopped in their tracks. In actual alloy nanowires though, atoms of the same element might cluster together to form short sections composed of the same elements.
Now, Zhun-Yong Ong and Gang Zhang of the A*STAR Institute Of high Performance Computing in Singapore have calculated the effects of such short-range order on the behavior of phonons("Enhancement and reduction of one-dimensional
heat conduction with correlated mass disorder"."Their results suggest that heat conduction in a nanowire does not just depend on the relative concentrations of the alloy atoms and the difference in their masses;
it also depends on how the atoms are distributed. Their model simulated an 88-micrometer-long nanowire containing 160,000 atoms of two different elements.
They found that when the nanowire was ordered more containing clusters of the same elements low-frequency phonons struggled to Move in contrast,
high-frequency phonons could travel much further than the average length of the ordered regions in the alloy.
The high-frequency phonons were more mobile than we imagined, says Ong. The researchers used their model to study the thermal resistance of a nanowire containing an equal mix of silicon and germanium atoms.
Short-range ordering of the atoms allowed high-frequency phonons to travel freely through the wire giving it a relatively low thermal resistance.
In contrast, a random distribution of alloy atoms resulted in a higher resistance over triple that of the ordered case for a 2. 5-micrometer-long wire.
If this disorder can be realized in real composite materials then we could tailor the thermal conductivity of the system,
says Ong. Understanding the relative contribution of low -and high-frequency phonons to heat conduction could also help researchers tune the thermal properties of nanowires in the laboratory.
For instance, the surface roughening of nanowires is known to reduce the thermal conductivity contribution of high-frequency phonons
says Ong. The researchers hope their model will help scientists design composite materials with low thermal conductivity.
One attractive application is thermoelectric devices, explains Ong. As these devices rely on a thermal differential,
a low thermal conductivity is desirable for optimal performance e
#Smart micelles for marine environments martmaterials that alter their structure in response to specific, controllable stimuli have applications in various fields, from biomedical science to the oil industry.
when moved from water to an electrolyte solution, such as salt water("Dual hydrophilic and salt responsive schizophrenic block copolymers synthesis and study of self-assembly behavior").
"The material could help improve coatings used to protect surfaces from the build up of biological contaminants, particularly surfaces under the sea.
Materials composed of segments of two different monomers, each with different characteristics, are known as block copolymers.
Vivek Vasantha at A*STAR Institute of Chemical and Engineering sciences together with scientists from across Singapore under the Innovative Marine Antifouling Solutions (IMAS) program developed a new block copolymer that can self-assemble into spherical micelle structures in
which one monomer forms the core and the other forms the outer shell. The monomers are the hydrophilic poly (ethylene glycol
or PEG, which mixes well with water, and the halophilic polysulfabetaine (PSB), which has a preference for salt solution. e created salt-responsive block copolymers that self-assemble in water to form either onventionalor nversemicelles, states Vasantha.
The conventional micelles form in deionized water and have a core of halophilic PSB with a hydrophilic PEG shell.
However, the team showed that the micelles reassemble themselves when immersed in salt solution; PEG formed the core,
and PSB formed the shell to create an nversemicelle. he material is controlled easily by salt alone, rather than by a combination of several stimuli like ph, temperature or light,
which some other smart materials require, explains Vasantha. t appears to be highly tolerant of fluctuations in ph and temperature too,
The researchers mixed the block copolymers with primer to create a nontoxic coating to replace traditional antifouling paint.
Current coatings to prevent fouling by marine organisms include toxic chemicals, and become ineffective after a short time
In nature, molecules called aquaporins, discovered in the 1990s, move water from one side of a biological membrane to another,
Now, researchers from the A*STAR Institute of Bioengineering and Nanotechnology have synthesized a much smaller molecule,
For some years, Huaqiang Zeng of the Institute of Bioengineering and Nanotechnology has led a team aiming to produce tubular molecules that could pipe water across membranes.
unfortunately, this tube was not particularly good at holding water in its central tunnel. Undeterred, Zeng team set out to modify that molecule.
when inserted into biomimetic membranes. Zeng thinks this and derivative molecules, may become ext-generation nanofiltration membranes for water purification applications,
including seawater desalination and wastewater reclamation. He says that osmotic agents often have to be at concentrations exceeding 100 millimolar to drive water movement in forward osmosis nanofiltration. f a proton gradient is used as the driving force instead,
the concentration difference needed would be exceedingly small.""Zeng says.""This would translate into huge energy savings on an industrial scale. l
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