Monday, November 28, 2011

Patent application for innovative film - possible Indium Tin Oxide replacement

On Nov. 5, Iroh filed a provisional patent application with the U.S. Patent Office for a polymer-based film with remarkable properties. The film is highly transparent and electrically conductive. It has potential uses in energy, including applications in solar and . It is economical, easily processed, durable, flexible, and heat resistant.

"Because of its properties, this film is very flexible," Iroh said. "I can envision a very thin solar panel that can be unrolled and applied, perhaps to an automobile, while the sun is shining, then peeled off and stored."

More importantly, Iroh's innovative film has the potential to replace a substance known as ITO, an abbreviation for . While the acronym may be unfamiliar to most consumers, ITO's uses are not. ITO is behind most touch-screen devices like and video kiosks. It appears in flat panel displays, electronic inks, and (LEDs).

ITO is also expensive and rare. It is fragile, lacks flexibility, and it is requires complicated processes to apply. All the major sources of Indium lie outside the United States, lending a strategic value to a suitable replacement for ITO.

Development of the new film grew out of Iroh's work on coatings.

"My initial focus was in composites, particularly laminated composites," he said. "It was for that work that I received my first patents."

After earning his Ph.D. from the University of Connecticut in 1990 and a Post-doctoral stint at Temple University, Iroh accepted a position at the University of Cincinnati as an assistant professor on September 1, 1991. His research attracted the attention of the Office of Naval Research, which asked him to look into coatings to protect metal. Iroh's projects earned acclaim from the Office of Naval Research, and he was named an ONR Young Investigator for 1995-1999. This honor was followed by others. Iroh was selected as the Sigma Xi Young Investigator at the University of Cincinnati for 2001, and was named a Resident Senior Research Associate at the Air Force Research Laboratory for 2002-2003. In 2004 he was elected as a Fellow of the Society for the Advancement of Materials and Process Engineering, SAMPE.

For the naval work, Iroh adapted a laminating process to apply coatings to steel.

"I was using what was then a new class of polymer, intrinsically conducting polymer, and applying it for corrosion prevention measures," he said.

Over the years, Iroh has tackled substantial problems related to coating materials. For example, adding trace amounts of various substances can improve corrosion prevention, but these "dopants" can be lost due to weather, defeating the purpose of the coating. Other coatings are very effective, but must be cured at high temperatures.

"We have found methods to reduce curing temperatures by more than 100 degrees Celsius," Iroh said. "That is very significant."

Effective coatings must meet a wide range of requirements, Iroh said. Cost is a factor, as is ease of application, environmental safety, ability to adhere and impact resistance.

The impact resistance of nanocomposite coatings has opened a fruitful partnership between Iroh's laboratory and Jackson State University, a historically black university in Mississippi. Funded by the Office of Naval Research, Jackson State students are working with Iroh's lab on low temperature systems for high-impact epoxy coatings.

"I would hope to see some of these students return here one day as graduate student," he said.

As Iroh gained more insight into the function of various substances as coatings, it occurred to him that these coating had useful properties, even if they were not coating something.

"A coating is essentially a film. What properties does this film possess?" Iroh said.

It was the question that led to the development of the highly transparent, electrically conductive, polymer-based nanocomposite film.

"This breakthrough will give us a unique place in the broader field of composites and energy research," he said. "This is an exciting development, and I am glad that my research group is very well positioned to continue to make a significant impact in this area."

Provided by University of Cincinnati (news : web)

Research team achieves critical step to opening elusive class of compounds to drug discovery

Taxol®, the trade name for a chemical called paclitaxel first discovered in 1967 in the bark of a yew tree, is a highly successful drug used to treat ovarian, breast, lung, liver, and other cancer types. No less than seven different research groups have designed several ways to produce Taxol® synthetically, beginning in the 1990s with a team led by K.C. Nicolaou, chair of the Scripps Research Department of Chemistry.

While each synthesis was a significant accomplishment, each has also been exceedingly complex and inefficient. Using all these methods collectively, researchers have produced less than 30 milligrams of synthetic Taxol®. Producing other chemicals from the same promising taxanes chemical group is nearly as challenging, vastly limiting access to them for research.

Building Ferraris

Finding an efficient way to produce Taxol® in sizable quantity in the laboratory remains one of the most sought-after and elusive goals in organic chemistry. If accomplished, it would open the door to producing countless other taxanes that are not accessible from nature. Past methods were devised using conventional schemes where researchers plot a linear path of increasingly complex molecules leading to a target compound. Creating each increasingly complex molecule along that line is an inefficient process that often requires numerous extra steps to prevent unwanted reactions or to correct other chemical complications. "It's like trying to convert a Toyota Corolla into a Ferrari instead of just building a Ferrari," said Baran.

To build the Ferrari, Baran and his team are taking a different route. In 2009, the researchers showed that by using an unconventional scheme they could produce a simpler relative of Taxol® called eudesmane. They analyzed this target and then created what Baran calls a retrosynthesis pyramid. This is a diagram with the target compound at the top and lower levels filled with molecules that could theoretically be modified to reach the level above them. Such a pyramid reveals not a set linear path, but a variety of path options open to chemical exploration.

With taxanes and related there are two main phases in production, the cyclase phase and oxidase phase. Working up the bottom half of the pyramid involves mostly well-understood chemistry. During this cyclase phase, researchers construct a chemical scaffolding that Baran likens to a Christmas tree to which ornaments must then be attached. The ornaments are primarily reactive oxygen molecules and this "decoration," or oxidation, phase is the most challenging.

The eudesmane synthesis was something like decorating the Charlie Brown Christmas tree, while a completed Taxol® production could be compared to the lighting of the famous multi-story Rockefeller Center tree.

In the new paper, Baran's group reports erecting that Rockefeller tree and adding the first few ornaments -- a molecule called taxadiene. "It's a Herculean task," said Baran of Taxol® synthesis, "What we're doing here is merely part one."

A conventional taxadiene synthesis is inefficient and involves 26 steps to produce. The Baran group's method involves just 10 steps to produce many times what has been previously synthesized -- more than sufficient for planned research to find a way to efficiently produce Taxol®.

Innovation Leads to Access

The taxadiene synthesis is more than just a midway stop on the way to Taxol®. The researchers chose this molecule intentionally because, like a Christmas tree that can be decorated in any number of ways, this molecule can be modified to create a wide range of taxanes of varying complexities.

This is key, because at its heart the research isn't only about finding a better way to produce Taxol®, even though the group is working toward that goal. The current commercial Taxol® production method, which involves culturing cells from the yew tree, is more economical than any new synthesis is likely to be.

Instead, Baran and his team are aiming to understand the processes used in nature to produce the compound, which are many times more efficient than those used by scientists to date. "It's my opinion that when there's a huge discrepancy between the efficiency of nature and humans, in the space between, there's innovation."

More specifically, Baran believes that while developing an efficient synthesis for Taxol®, they will gain a fundamentally improved understanding of the chemistry involved and develop more widely applicable techniques. Such innovation could allow production of a whole range of taxanes currently inaccessible for drug discovery research either because the quantities researchers can produce are vanishingly small, or because they can't produce them at all. Control of the taxane oxidation process therefore offers the potential for discovering new and important drugs, perhaps even one or more that is better at fighting specific cancers than Taxol®.

Establishing the remaining steps between taxadiene and ® or other more complex taxanes remains a challenging task that Baran estimates will take years. "Nature has a choreography in the way she decorates the tree," he said. "It's a precise dance she has worked out over millennia. We have to figure out a way to bring that efficiency to the laboratory setting."

The project, led by Scripps Research chemist Phil Baran, is described November 6, 2011 in an advance, online issue of the journal Nature Chemistry.

Provided by The Scripps Research Institute (news : web)

USC team develops promising polymer for solar cells

One way to do this, researchers believe, is to create a based material that could be used instead of . Such material would cost less to produce and have sufficient bendiness that it could be printed onto bendable surfaces in much the same way newspapers are mass printed, i.e. via giant rollers. Up to now though, figuring out how to create such a polymer that is as efficient at converting sunlight into energy as silicon-based cells, hasn’t really worked out.

Now though, a team working out of USC, headed by Alan Heeger, who along with Guillermo Bazan won the Nobel Prize in Physics back in 2000 for groundbreaking work they did on polymer cells, believe they have made another breakthrough. In their paper, published in Nature Materials, they say they’ve figured out a way to use an organic material with a low molecular weight (small molecule) to produce a solar cell that is every bit as efficient as current silicon technology.

The small molecule technology came about as the result of work done by Bazan, who used theory and lots of trial and error to produce just the right material; one that could, unlike many others that had been tried, be formed into a layer that could be applied to other . Heeger then took the lead in applying the new material in a solar cell. The end result the team says, is a solar cell capable of matching the 6.7% energy efficiency of silicon cells. And not only that, they believe with some tweaking, they can get it to 9%.

Unfortunately, there is a dark cloud looming ahead, and that is because the team isn’t sure just yet if the new material will work as designed once it’s ramped up to commercial size. In the past, when polymers have been sized up, their efficiencies went down.

More information: Solution-processed small-molecule solar cells with 6.7% efficiency, Nature Materials (2011) doi:10.1038/nmat3160

Organic photovoltaic devices that can be fabricated by simple processing techniques are under intense investigation in academic and industrial laboratories because of their potential to enable mass production of flexible and cost-effective devices1, 2. Most of the attention has been focused on solution-processed polymer bulk-heterojunction (BHJ) solar cells3, 4, 5, 6, 7. A combination of polymer design, morphology control, structural insight and device engineering has led to power conversion efficiencies (PCEs) reaching the 6–8% range for conjugated polymer/fullerene blends8, 9. Solution-processed small-molecule BHJ (SM BHJ) solar cells have received less attention, and their efficiencies have remained below those of their polymeric counterparts10. Here, we report efficient solution-processed SM BHJ solar cells based on a new molecular donor, DTS(PTTh2)2. A record PCE of 6.7% under AM 1.5?G irradiation (100?mW?cm-2) is achieved for small-molecule BHJ devices from DTS(PTTh2)2:PC70BM (donor to acceptor ratio of 7:3). This high efficiency was obtained by using remarkably small percentages of solvent additive (0.25%?v/v of 1,8-diiodooctane, DIO) during the film-forming process, which leads to reduced domain sizes in the BHJ layer. These results provide important progress for solution-processed organic photovoltaics and demonstrate that solar cells fabricated from small donor molecules can compete with their polymeric counterparts.

? 2011

Team develops speedy software designed to improve drug development

Similarly, when a newly created drug doesn’t bind well to its intended target, the drug won’t work. Scientists are then forced to go back to the lab, often with very little indication about why the binding was weak. The next step is to choose a different “combination” and hope for better results. Georgia Tech researchers have now generated a computer model that could help change that blind process.

Symmetry-adapted perturbation theory (SAPT) allows scientists to study interactions between molecules, such as those between a drug and its target. In the past, computer algorithms that study these noncovalent interactions have been very slow, limiting the types of molecules that can be studied using accurate quantum mechanical methods. A research team headed by Georgia Tech Professor of Chemistry David Sherrill has developed a computer program that can study larger molecules (more than 200 atoms) faster than any other program in existence. 

“Our fast energy component analysis program is designed to improve our knowledge about why certain molecules are attracted to one another,“ explained Sherrill, who also has a joint appointment in the School of Computational Science and Engineering. “It can also show us how interactions between molecules can be tuned by chemical modifications, such as replacing a hydrogen atom with a fluorine atom.  Such knowledge is key to advancing rational drug design.”

Georgia tech develops speedy software designed to improve drug development

Computer Program Quickly Analyzes Molecular Interactions II

The algorithms can also be used to improve the understanding of crystal structures and energetics, as well as the 3D arrangement of biological macromolecules. Sherrill’s team used the to study the interactions between DNA and proflavine; these interactions are typical of those found between DNA and several anti-cancer drugs. The findings are published this month in the Journal of Chemical Physics.

Rather than selling the software, the Georgia Tech researchers have decided to distribute their code free of charge as part of the open-source computer program PSI4, developed jointly by researchers at Georgia Tech, Virginia Tech, the University of Georgia and Oak Ridge National Laboratory.  It is expected to be available in early 2012.

“By giving away our source code, we hope it will be adopted rapidly by researchers in pharmaceuticals, organic electronics and catalysis, giving them the tools they need to design better products,” said Sherrill.

Sherrill’s team next plans to use the software to study the noncovalent interactions involving indinavir, which is used to treat HIV patients.

Provided by Georgia Institute of Technology (news : web)