#Study suggests light may be skewing lab tests on nanoparticles'health effects Truth shines a light into dark places.
That's what recent findings at the National Institute of Standards and Technology (NIST) show about methods for testing the safety of nanoparticles.
It turns out that previous tests indicating that some nanoparticles can damage our DNA may have been skewed by inadvertent light exposure in the lab. Nanoparticles made of titanium dioxide are a common ingredient in paint
scientists have accepted long that these nanoparticles would not damage cells by forming free radicals from light activation.
However, some recent studies using cells suggest that titanium dioxide can damage DNA even in darkness disturbing possibility.
whether light was required indeed for the nanoparticles to cause DNA damage.""We didn't set out to test the safety of the particles themselveshat's for someone else to determine,
"The NIST team exposed samples of DNA to titanium dioxide nanoparticles under three different conditions: Some samples were exposed in the presence of visible
or ultraviolet light did the DNA form base lesions, a form of DNA damage associated with attack by radicals.
"The results suggest that titanium dioxide nanoparticles do not damage DNA when kept in the dark,
must be controlled carefully before drawing conclusions about nanoparticle effects on DNA
#Research team developing injectable treatment for soldiers wounded in battle Internal bleeding is a leading cause of death on the battlefield,
but a new, injectable material developed by team of researchers from Texas A&m University and the Massachusetts institute of technology could buy wounded soldiers the time they need to survive by preventing blood loss from serious internal injuries.
The potentially lifesaving treatment comes in the form of a biodegradable gelatin substance that has been embedded with nano-sized silicate discs that aid in coagulation.
Once injected, the material locks into place at the site of the injury and rapidly decreases the time it takes for blood to clot in some instances by a whopping 77 percent,
says Akhilesh Gaharwar, assistant professor of biomedical engineering at Texas A&m and member of the research team.
The team's findings are detailed in the scientific journal ACS Nano and supported by the U s army Research Office.
Gaharwar envisions the biomaterial being preloaded into syringes that soldiers can carry with them into combat situations.
If a soldier experiences a penetrating, incompressible injury one where it is difficult if not impossible to apply the pressure needed to stop the bleeding he
or she can inject the material into the wound site where it will trigger a rapid coagulation
and provide enough time to get to a medical facility for treatment, he says.""The time to get to a medical facility can take a half hour to an hour,
"Our material's combination of injectability, rapid mechanical recovery, physiological stability and the ability to promote coagulation result in a hemostat for treating incompressible wounds in out-of-hospital, emergency situations,
and his colleagues solidifies at the site of the wound and begins promoting coagulation in the targeted area.
patches and sealants.""Most of these penetrating injuries, which today are the result of explosive devices,
rupture blood vessels and create internal hemorrhages through which a person is constantly losing blood,"Gaharwar notes."
"You can't apply pressure inside your body, so you have to have something that can quickly clot the blood without needing pressure."
Hydrogels are used biodegradable materials in a number of biomedical applications because of their compatibility with the body and its processes.
By inserting two-dimensional nanoplatelets into the hydrogel, the team was able to tweak the mechanical properties of material.
and then regain its shape once inside the body something necessary for locking itself in place at the wound site,
represents a new direction in biomedical engineering. Two-dimensional materials are ultrathin substances with high surface area but a thickness of a few nanometers or less.
Think of a sheet of paper but on a much smaller scale. For example, a sheet of paper is 100,000 nanometers thick;
Gaharwar's nanoplatelets are one nanometer thick. Gaharwar and his colleagues employ two-dimensional, disc-shaped particles known as synthetic silicate nanoplatelets.
Because of their shape, these platelets have a high surface area, he explains. The structure, composition and arrangement of the platelets result in both positive and negative charges on each particle.
These charges, Gaharwar explains, cause the platelets to interact with the hydrogel in a unique way.
these disc-shaped nanoplatelets interact with blood to promote clotting, Gaharwar says, noting that animal models have shown clot formation occurring in about one minute as opposed to five minutes without the presence of these nanoparticles.
Animal model, he adds, also have demonstrated the formation of lifesaving clot formations when the enhanced biomaterial was used."
"These 2d, silicate nanoparticles are unprecedented in the biomedical field, and their use promises to lead to both conceptual and therapeutic advances in the important and emerging field of tissue engineering, drug delivery, cancer therapies and immune engineering,
"Gaharwar says. Encouraged by its results, the team plans on further enhancing the biomaterial so that it can initiate regeneration of damaged tissues through the formation of new blood vessels,
#Quantum dot technology makes LCD TVS more colorful energy-efficient If LCD TVS start getting much more colorful and energy-efficient in the next few years,
it will probably be thanks to MIT spinout QD Vision, a pioneer of quantum dot television displays.
Quantum dots are light-emitting semiconductor nanocrystals that can be tuned by changing their size, nanometer by nanometer to emit all colors across the visible spectrum.
By tuning these dots to red and green, and using a blue backlight to energize them,
QD Vision has developed an optical component that can boost the color gamut for LCD televisions by roughly 50 percent,
and increase energy-efficiency by around 20 percent. Last June, Sony used QD Vision product, called Color IQ, in millions of its Bravia riluminostelevisions, marking the first-ever commercial quantum dot display.
In September, Chinese electronics manufacturer TCL began implementing Color IQ into certain models. These are currently only available in China,
ecause a lot of growth for the TV market is there, says Seth Coe-Sullivan Phd, cofounder and chief technology officer of QD Vision,
who co-invented the technology at MIT. But within a couple of months, he says, these displays will be olling out to the rest of the world.
Replacing the bulb In conventional LCD TVS pixels are illuminated by a white LED backlight that passes through blue, red,
and green filters to produce the colors on the screen. But this actually requires phosphors to convert a blue light to white;
because of this process, much light is lost, and displays only reach about 70 to 80 percent of the National Television Standard Committee color gamut.
Manufacturers can potentially boost color by incorporating more LEDS, but this costs more and requires more energy to run.
Color IQ is a thin glass tube, filled with quantum dots tuned to red and green, that implemented during the synthesis process.
Manufacturers use a blue LED in the backlight, but without the need for conversion phosphors.
As blue light passes through the Color IQ tube, some light shines through as pure blue light
while some is absorbed and re-emitted by the dots as pure red and pure green.
With more light shining through the pixels, LCD TVS equipped with Color IQ produce 100 percent of the color gamut,
with greater power efficiency than any other technology. he value proposition is that you are not changing the display,
all youe doing is replacing the light bulb, and yet the entire display looks much better.
The colors are much more vivid known as much more saturated allowing you to generate a much more believable image,
says QD Vision cofounder and scientific advisor Vladimir Bulovic, the Fariborz Maseeh Chair in Emerging Technology at MIT, who also co-leads the MIT Innovation Initiative.
Green from radle to gravewhile QD Vision aims to bring consumers more color-saturated displays,
Color IQ also has a positive environmental impact, which earned the company the Presidential Green Chemistry Challenge Award from the U s. Environmental protection agency in October.
While developing its Color IQ which replaces phosphor in displays the company developed a much greener synthesis, according to the EPA.
This synthesis involves replacing alkyl phosphine solvents with long-chain hydrocarbons, which are less hazardous,
and replacing cadmium and zinc building blocks with less hazardous materials. This eliminates 40 000 gallons of toxic solvents and 100 kilograms of toxic cadmium waste in U s. production each year.
Using the components in 20 million TVS is projected to save 600 million kilowatt-hours of electricity per year worldwide enough electricity to power 50,000 average U s. homes. ee been able to show, cradle to grave,
from the materials we use to how we make it to how it put to rest, that there an environmental benefit,
Other technologies, called organic light-emitting diode (OLED) displays, use an organic compound to reach upward of 100 percent of the color gamut
LCD TVS made with Color IQ are just as colorful but are made for a few hundred dollars less
and operate with greater efficiency, Coe-Sullivan says. Lighting to displays, and back QD Vision technology began at MIT more than a decade ago.
Coe-Sullivan, then a Phd student in electrical engineering and computer science, was working with Bulovic and students of Moungi Bawendi, the Lester Wolfe Professor in Chemistry,
on implementing quantum dots into electronic devices. In a study funded by MIT Deshpande Center for Technological Innovation, Coe-Sullivan, QD Vision cofounder Jonathan Steckel Phd 6,
and others developed a pioneering technique for producing quantum dot LEDS (QLEDS). To do so, they sandwiched a layer of quantum dots, a few nanometers thick, between two organic thin films.
When electrically charged, the dots illuminated a light bulb 25 times more efficiently than traditional devices.
The resulting paper, published in Nature in 2002, became a landmark in the quantum dot-devices field. oon venture capitalists were calling Vladimir,
asking if we spin a company out, Coe-Sullivan says. Coe-Sullivan started toying around with the idea of starting a company.
Then, a chance encounter at a cocktail party at the Martin Trust Center for MIT Entrepreneurship with a former classmate
QD Vision cofounder Greg Moeller MBA 2 sped things along. Early in the evening, the two started discussing Coe-Sullivan QLED advancements;
they soon found themselves up all night in a lab in Building 13, fleshing out a business strategy.
Following that conversation, Coe-Sullivan enrolled in 15.390 (New Ventures) to further develop a business model. hat led to the more rigorous formation of a sales and marketing plans,
and product creation, he says. In 2004 Coe-Sullivan, Bulovic, Moeller, Steckel, and mentor Joe Caruso launched QD Vision.
In 2010, the company launched its first product, a QD light bulb, with partner Nexxus Lighting.
However, realizing this $100 light bulb would soon need to sell for $10 to remain competitive
quantum dot displays. aking a transition like that from lighting to displays tests the nerves of folks involved, from top to bottom,
Pooling all resources into displays, the company eventually caught the eye of Sony, and last year became the first to market with a quantum dot display.
Today, QD Vision remains one of only two quantum dot display companies that have seen their products go to market.
Now, with a sharp rise in commercial use, quantum dot technologies are positioned to penetrate the display industry
Coe-Sullivan says. Along with Color IQ-powered LCD TVS, Amazon released a quantum dot Kindle last year,
and Asus has a quantum dot notebook. nd there nothing in between that quantum dots can address,
he says. In the future, Coe-Sullivan adds, QD Vision may even go back and tackle its first challenge:
QD light bulbs. he market has stabilized quite a bit, he says. omewhere down the line, we think there an application
and value proposition for quantum dot lighting. n
#Streamlining thin film processing saves time energy Energy storage devices and computer screens may seem worlds apart but they're not.
When associate professor Qi Hua Fan of the electrical engineering and computer science department set out to make a less expensive supercapacitor for storing renewable energy he developed a new plasma technology that will streamline the production of display screens.
For his work on thin film and plasma technologies Fan was named researcher of the year for the Jerome J. Lohr College of Engineering.
His research focuses on nanostructured materials used for photovoltaics energy storage and displays. Last spring Fan received a proof-of-concept grant from the Department of energy through the North Central Regional Sun Grant Center to determine
if biochar a byproduct of the a process that converts plants materials into biofuel could be used in place of expensive activated carbon to make electrodes for supercapacitors.
Sun Grant promotes collaboration among researchers from land-grant institutions government agencies and the private sector to develop
and commercialize renewable bio-based energy technologies. The proof-of-concept grants allow researchers to advance promising research to the next level of toward product development and commercialization.
The amount of charge stored in a capacitor depends on the surface area Fan explained and the biochar nanoparticles can create an extremely large surface area
which can then hold more charge. He deposits the biochar on a substrate using a patent-pending electrochemical process he developed
and licensed to Applied Nanofilms LLC in Brookings. Applied Nanofilms and Wintek a company that makes flat panel displays for notebooks
and touch screens in Ann arbor Michigan provided matching funds. Through this project Fan developed a faster way of treating the biochar particles using a new technology called plasma activation.
Treating means you use plasma to change the material surface such as creating pores Fan said.
The plasma treatment activates the biochar in five minutes and at room temperature Fan explained. Conventional chemical activation takes several hours to complete
and must be done at high temperatures approximately 1760 degrees Fahrenheit. This saves energy and is much more efficient Fan said.
In this project he has been collaborating with assistant professor Zhengrong Gu in the agricultural and biosystems engineering department
whose research focuses on energy storage materials and devices. They plan to use these promising results to apply for federal funding.
The technique that treats biochar electrodes for supercapacitors can also be used in making displays explained Fan who was a research scientist at Wintek more than 10 years ago.
Since last fall Fan has been collaborating with Wintek on ways of producing more efficient better performing materials such as silicon and carbon thin films for the company's displays.
Plasma processing is a very critical technology in modern optoelectronic materials and devices Fan explained.
The high-energy plasma can deposit highly transparent and conductive thin films create high quality semiconductors and pattern micro-or nanoscale devices thus making the display images brighter and clearer.
Fan will work with Wintek to develop a prototype plasma system. The activation method has the potential to improve production efficiency saving time and energy he noted d
#New nanocomposites for aerospace and automotive industries The Center for Research in Advanced Materials (CIMAV) has developed reinforced graphite nanoplatelets seeking to improve the performance of solar cell materials.
The work done by Liliana Licea Jimenez uses this material because it has a large power capacity.
These polymer-based nanocomposites are reinforced with graphite nanoplatelets for use in industry. Nanocomposites are formed by two
or more phases in this case by reinforced graphite nanoplatelets. The sectors focused on the use of these nanomaterials are diverse;
nanoplatelets impart new properties to materials; this allows us to move into the automotive construction aerospace textile and electronics sectors
which are demanding and where the use of nanomaterials is an opportunity explains Licea Jimenez.
According to the specialist at CIMAV the research is applied already in some concept testing for mechanical and thermal modification in the construction industry.
Additionally nanocomposite materials are used already in fenders and panels in the automotive and textile industry.
The development of nanocomposites in this research center is an opportunity for different industry sectors; graphite nanoplatelets give added value to the product as they improve its mechanical thermal and electrical properties.
And they have an impact on the industry because the business demands are increasing and the use of nanocomposites is an opportunity to improve the product.
Even some of the companies we have worked with mentioned in several forums that they have had a good response in the use of these nanomaterials.
She also affirms that the nanocomposites Laboratory in Monterey has achieved success but recognizes that they need to engage with sectors such as aeronautics among other areas.
Jimenez Licea indicates that in addition to companies in the northern state of Nuevo Leon there are companies in other states that have shown interest in polymer nanocomposites;
It is an advantage to work with research projects demanded by the industry because they have a specific function for each company.
This is because each nanocomposite is a material that has two or more constituents in this case the polymer and a nano-sized reinforcing material:
the graphite nanoplatelets s
#Graphene/nanotube hybrid benefits flexible solar cells Rice university scientists have invented a novel cathode that may make cheap, flexible dye-sensitized solar cells practical.
The Rice lab of materials scientist Jun Lou created the new cathode, one of the two electrodes in batteries,
from nanotubes that are bonded seamlessly to graphene and replaces the expensive and brittle platinum-based materials often used in earlier versions.
The discovery was reported online in the Royal Society of Chemistry's Journal of Materials Chemistry A. Dye-sensitized solar cells have been in development
since 1988 and have been the subject of countless high school chemistry class experiments. They employ cheap organic dyes
drawn from the likes of raspberries, which cover conductive titanium dioxide particles. The dyes absorb photons and produce electrons that flow out of the cell for use;
a return line completes the circuit to the cathode that combines with an iodine-based electrolyte to refresh the dye.
While they are not nearly as efficient as silicon-based solar cells in collecting sunlight and transforming it into electricity,
dye-sensitized solar cells have advantages for many applications, according to co-lead author Pei Dong, a postdoctoral researcher in Lou's lab."The first is that they're low-cost,
because they can be fabricated in a normal area, "Dong said.""There's no need for a clean room.
They're semitransparent, so they can be applied to glass, and they can be used in dim light;
they will even work on a cloudy day.""Or indoors,"Lou said.""One company commercializing dye-sensitized cells is embedding them in computer keyboards
and mice so you never have to install batteries. Normal room light is sufficient to keep them alive."
"The breakthrough extends a stream of nanotechnology research at Rice that began with chemist Robert Hauge's 2009 invention of a"flying carpet"technique to grow very long bundles of aligned carbon nanotubes.
In his process, the nanotubes remained attached to the surface substrate but pushed the catalyst up as they grew.
The graphene/nanotube hybrid came along two years ago. Dubbed"James'bond"in honor of its inventor, Rice chemist James Tour, the hybrid features a seamless transition from graphene to nanotube.
The graphene base is grown via chemical vapor deposition and a catalyst is arranged in a pattern on top.
When heated again carbon atoms in an aerosol feedstock attach themselves to the graphene at the catalyst,
which lifts off and allows the new nanotubes to grow. When the nanotubes stop growing,
the remaining catalyst (the"carpet")acts as a cap and keeps the nanotubes from tangling.
The hybrid material solves two issues that have held back commercial application of dye-sensitized solar cells,
Lou said. First, the graphene and nanotubes are grown directly onto the nickel substrate that serves as an electrode,
eliminating adhesion issues that plagued the transfer of platinum catalysts to common electrodes like transparent conducting oxide.
Second the hybrid also has less contact resistance with the electrolyte, allowing electrons to flow more freely.
The new cathode's charge-transfer resistance, which determines how well electrons cross from the electrode to the electrolyte,
was found to be 20 times smaller than for platinum-based cathodes, Lou said. The key appears to be the hybrid's huge surface area,
estimated at more than 2, 000 square meters per gram. With no interruption in the atomic bonds between nanotubes and graphene, the material's entire area, inside and out, becomes one large surface.
This gives the electrolyte plenty of opportunity to make contact and provides a highly conductive path for electrons.
Lou's lab built and tested solar cells with nanotube forests of varying lengths The shortest,
which measured between 20-25 microns, were grown in 4 minutes. Other nanotube samples were grown for an hour
and measured about 100-150 microns. When combined with an iodide salt-based electrolyte and an anode of flexible indium tin oxide,
titanium dioxide and light-capturing organic dye particles, the largest cells were only 350 microns thickhe equivalent of about two sheets of papernd could be flexed easily and repeatedly.
Tests found that solar cells made from the longest nanotubes produced the best results and topped out at nearly 18 milliamps of current per square centimeter
compared with nearly 14 milliamps for platinum-based control cells. The new dye-sensitized solar cells were as much as 20 percent better at converting sunlight into power,
with an efficiency of up to 8. 2 percent, compared with 6. 8 for the platinum-based cells.
Based on recent work on flexible graphene-based anode materials by the Lou and Tour labs and synthesized high-performance dyes by other researchers,
Lou expects dye-sensitized cells to find many uses.""We're demonstrating all these carbon nanostructures can be used in real applications,
"he said
#Bio-inspired bleeding control: Researchers synthesize platelet-like nanoparticles that can do more than clot blood (Phys. org) Stanching the free flow of blood from an injury remains a holy grail of clinical medicine.
Controlling blood flow is a primary concern and first line of defense for patients and medical staff in many situations from traumatic injury to illness to surgery.
If control is established not within the first few minutes of a hemorrhage further treatment and healing are impossible.
At UC Santa barbara researchers in the Department of Chemical engineering and at Center for Bioengineering (CBE) have turned to the human body's own mechanisms for inspiration in dealing with the necessary and complicated process of coagulation.
By creating nanoparticles that mimic the shape flexibility and surface biology of the body's own platelets they are able to accelerate natural healing processes
while opening the door to therapies and treatments that can be customized to specific patient needs.
This is a significant milestone in the development of synthetic platelets as well as in targeted drug delivery said Samir Mitragotri CBE director who specializes in targeted therapy technologies.
Results of the researchers'findings appear in the current issue of the journal ACS Nano.
The process of coagulation is familiar to anyone who has suffered even the most minor of injuries such as a scrape or paper cut.
Blood rushes to the site of the injury and within minutes the flow stops as a plug forms at the site.
The tissue beneath and around the plug works to knit itself back together and eventually the plug disappears.
But what we don't see is the coagulation cascade the series of signals and other factors that promote the clotting of blood
and enable the transition between a free-flowing fluid at the site and a viscous substance that brings healing factors to the injury.
Coagulation is actually a choreography of various substances among the most important of which are platelets the blood component that accumulates at the site of the wound to form the initial plug.
While these platelets flow in our blood they're relatively inert said graduate student researcher Aaron Anselmo lead author of the paper.
As soon as an injury occurs however the platelets because of the physics of their shape and their response to chemical stimuli move from the main flow to the side of the blood vessel wall
and congregate binding to the site of the injury and to each other. As they do so the platelets release chemicals that call other platelets to the site eventually plugging the wound.
But what happens when the injury is too severe or the patient is on anticoagulation medication
or is impaired otherwise in his or her ability to form a clot even for a modest or minor injury?
That's where platelet-like nanoparticles (PLNS) come in. These tiny platelet-shaped particles that behave just like their human counterparts can be added to the blood flow to supply
or augment the patient's own natural platelet supply stemming the flow of blood and initiating the healing process
while allowing physicians and other caregivers to begin or continue the necessary treatment. Emergency situations can be brought under control faster injuries can heal more quickly
and patients can recover with fewer complications. We were actually able to render a 65 percent decrease in bleeding time compared to no treatment said Anselmo.
According to Mitragotri the key lies in the PLNS'mimicry of the real thing. By imitating the shape
and flexibility of natural platelets PLNS can also flow to the injury site and congregate there.
With surfaces functionalized with the same biochemical motifs found in their human counterparts these PLNS also can summon other platelets to the site
and bind to them increasing the chances of forming that essential Plug in addition and very importantly these platelets are engineered to dissolve into the blood after their usefulness has run out.
This minimizes complications that can arise from emergency hemostatic procedures. The thing about hemostatic agents is that you have to intervene to the right extent said Mitragotri.
If you do too much you cause problems. If you do too little you cause problems. These synthetic platelets also let the researchers improve on nature.
According to Anselmo's investigations for the same surface properties and shape nanoscale particles can perform even better than micron-size platelets.
Additionally this technology allows for customization of the particles with other therapeutic substances medications therapies
and such that patients with specific conditions might need. This technology could address a plethora of clinical challenges said Dr. Scott Hammond director of UCSB's Translational Medicine Research Laboratories.
One of the biggest challenges in clinical medicine right now which also costs a lot of money is that we're living longer
and people are more likely to end up on blood thinners. When an elderly patient presents at a clinic it's a huge challenge
because you have no idea what their history is and you might need an intervention.
With optimizable PLNS physicians would be able to strike a finer balance between anticoagulant therapy
and wound healing in older patients by using nanoparticles that can target where clots are forming without triggering unwanted bleeding.
In other applications bloodborne pathogens and other infectious agents could be minimized with antibiotic-carrying nanoparticles.
Particles could be made to fulfill certain requirements to travel to certain parts of the body across the blood-brain barrier for instance for better diagnostics
and truly targeted therapies. Additionally according to the researchers these synthetic platelets cost relatively less and have a longer shelf life than do human platelets a benefit in times of widespread emergency
or disaster when the need for these blood components is at its highest and the ability to store them onsite is essential.
Explore further: Shape of things to come in platelet mimicr r
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