Sunday, December 11, 2011

NYU-Poly professor developing bioplastic that acts like regular plastic

The professor of chemical and biological science and partners recently received grants from the National Science Foundation (NSF) to develop an improved, bio-based alternative to petroleum-based plastics that could be used in everything from bottles to garment bags. One of the grants is for $590,000 and will fund research between Gross and PolyNew, a small Colorado-based company that produces nanocomposites. NYU-Poly will coordinate and also collaborate on the project, which is funded through the NSF’s Partnerships for Innovation program, an effort to commercialize academic research by requiring that grantees collaborate with small businesses. The other is for $150,000 and will fund research by Gross’s SyntheZyme startup company. 

Both projects will build on a method Gross created for producing a strong, highly ductile bioplastic using yeast. The Journal of the American Chemical Society published Gross’s findings in 2010. His method involves a fairly quick, relatively low-cost way to use engineered yeast to make large quantities of omega-hydroxyfatty acids from fatty acids of plant oils. When strung together, the omega-hydroxyfatty acids form a polymer, or .

“It was a very exciting development in the field, and not just because we created a bioplastic with desirable properties,” says Gross. “The process uses no fossil fuels, and every step is biologically friendly, from fatty acids in plant oils through the end product, which is a versatile, 100 percent biodegradable plastic.”

The polymer from omega-hydroxyfatty acids Gross created will provide tough and flexible new bioplastics. PolyNew will develop natural fibers from cellulose known as cellulose nanowhiskers that will act as a reinforcing agent increasing SyntheZyme’s bioplastic’s rigidity. SyntheZyme has also developed blends of their bioplastics with a commercial produced by NatureWorks known as polylactic acid. Various combinations of SyntheZyme’s polymer from omega-hydroxyfatty acids with polylactic acid and cellulose nanowhiskers will lead to the development of a suite of new bioplastics for uses in a wide range of applications including disposable gloves, multilayer food packaging films, produce bags, bottles, fibers in clothing and carpets, and molded plastic articles used as casings for electronic products.   

The U.S. Defense Advanced Research Projects Agency (DARPA) tapped Gross’s laboratory at NYU-Poly to develop his original bioplastics. The further development of that work led in part to the formation of SyntheZyme, which is a member of the New York City Accelerator for a Clean and Renewable Economy (NYC ACRE), a new-business accelerator for clean technology and renewable energy companies. NYU-Poly operates NYC ACRE with funding from the New York State Energy Research and Development Authority (NYSERDA) within the Varick Street Incubator, which is a partnership of NYU-Poly, the New York City Economic Development Corporation and Trinity Real Estate.  

Provided by Journal of American Chemical Society

'Fool's gold' aids discovery of new options for cheap, benign solar energy

These new compounds, unlike some solar cell materials made from rare, expensive or toxic elements, would be benign and could be processed from some of the most abundant elements on Earth. Findings on them have been published in Advanced Energy Materials, a professional journal.

Iron pyrite itself has little value as a future compound, the scientists say, just as the brassy, yellow-toned mineral holds no value compared to the precious metal it resembles. But for more than 25 years it was known to have some desirable qualities that made it of interest for solar energy, and that spurred the recent research.

The results have been anything but foolish.

"We've known for a long time that pyrite was interesting for its solar properties, but that it didn't actually work," said Douglas Keszler, a distinguished professor of chemistry at OSU. "We didn't really know why, so we decided to take another look at it. In this process we've discovered some different materials that are similar to pyrite, with most of the advantages but none of the problems.

"There's still work to do in integrating these materials into actual ," Keszler said. "But fundamentally, it's very promising. This is a completely new insight we got from studying fool's ."

Pyrite was of interest early in the solar energy era because it had an enormous capacity to absorb solar energy, was abundant, and could be used in layers 2,000 times thinner than some of its competitors, such as silicon. However, it didn't effectively convert the solar energy into electricity.

In the new study, the researchers found out why. In the process of creating solar cells, which takes a substantial amount of heat, pyrite starts to decompose and forms products that prevent the creation of electricity.

Based on their new understanding of exactly what the problem was, the research team then sought and found compounds that had the same capabilities of pyrite but didn't decompose. One of them was iron silicon sulfide.

"Iron is about the cheapest element in the world to extract from nature, silicon is second, and sulfur is virtually free," Keszler said. "These compounds would be stable, safe, and would not decompose. There's nothing here that looks like a show-stopper in the creation of a new class of solar energy materials."

Work to continue the development of the materials and find even better ones in the same class will continue at the National Renewable Energy Laboratory in Colorado, which collaborated on this research.

The work was done at the Center for Inverse Design, a collaborative initiative of the College of Science and College of Engineering at OSU, formed two years ago with a $3 million grant from the U.S. Department of Energy. It was one of the new Energy Frontier Research Centers set up through a national, $777 million federal program to identify energy solutions for the future.

The OSU program is different from traditional science, in which the process often is to discover something and then look for a possible application. In this center, researchers start with an idea of what they want and then try to find the kind of materials, atomic structure or even construction methods it would take to achieve it.

Finding cheap, environmentally benign and more efficient materials for solar energy is necessary for the future growth of the industry, researchers said.

"The beauty of a material such as this is that it is abundant, would not cost much and might be able to produce high-efficiency solar cells," Keszler said. "That's just what we need for more broad use of solar energy."

Provided by Oregon State University (news : web)

New technique puts chemistry breakthroughs on the fast track

The researchers report this month in the journal Science a technique to accomplish "accelerated serendipity" by using robotics to perform more than 1,000 chemical reactions a day with molecules never before combined. In a single day of trials, the Princeton researchers discovered a shortcut for producing pharmaceutical-like compounds that shaves weeks off the traditional process, the researchers report.

The basis of the research was to combine new technology with a unique, rapid-reaction approach that could allow chemists to explore unheard-of and potentially important chemical combinations without devoting years to the pursuit, explained senior researcher and co-author David MacMillan, the James S. McDonnell Distinguished University Professor of Chemistry at Princeton and chair of the department. MacMillan worked with lead author Andrew McNally, a research associate in MacMillan's lab, and Princeton graduate student and co-author Christopher Prier.

"This is a very different way of approaching how we come up with valuable chemical reactions," MacMillan said.

"Our process is designed specifically for serendipity to occur. The molecules that should be combined are those for which the result is unknown," he said. "In our lab, we used this technique to make new findings in a much more routine and rapid fashion, and we show that if you have enough events involved, serendipity won't be rare. In fact, you can enable it to happen on almost a daily basis."

The MacMillan lab's technique does more than just expedite the discovery process — the researchers actually developed a unique framework for creating new materials or finding better ways of producing existing ones, said Stephen Buchwald, a professor of chemistry at the Massachusetts Institute of Technology.

"This is a particularly brilliant approach," said Buchwald, who is familiar with the work but had no role in it.

"Usually, one takes molecules that one thinks will react and tries to figure out the best way to achieve that reaction," he said. "This team took molecules for which there was no obvious reaction between them and looked for 'accidental' reactivity. This approach could be useful for any field that requires new types of matter or a more efficient means of synthesizing known compounds."

Illustrating that principle, the Princeton researchers combined two molecules with no history of reacting to generate the type of chemical functionality found in eight of the world's top 100 pharmaceuticals, MacMillan said. The reaction involved a nitrogen-based molecule known as an amine that has a hydrogen and carbon pair, and a circle of atoms stabilized by their bonds known as an .

The result was a carbon-nitrogen molecule with an aromatic ring, a building block of many amine-based pharmaceuticals, explained MacMillan. This class of drugs mimics natural amine molecules in the body and includes medications such as antihistamines, decongestants and antidepressants. In drug development, chemists "tweak" organic molecules to enhance their ability to bind with and disrupt enzymes in a biological system, which is how pharmaceuticals basically operate, MacMillan said. A molecule with an aromatic ring has increased reactivity and makes the tweaking process much easier, he said, but attaching the aromatic ring is a process in itself that typically involves two to three weeks of successive chemical reactions.

The reaction MacMillan and his team found provides a quick way around that.

"We quickly realized that any pharmaceutical research chemist could immediately take these very simple components and, via a reaction no one had known about, start assembling molecules with an adjacent aromatic ring rapidly," MacMillan said.

"Instead of having to construct these important molecules circuitously using lots of different chemistry over a period of days if not weeks, we can now do it immediately in the space of one chemical reaction in one day."

Buchwald said that the rapid production of this molecule is as surprising as it is significant.

"The way these types of molecules — alpha aryl amines — were produced in this project is highly efficient, and no person could truthfully say that they would have predicted this reaction," Buchwald said. "This group was able to take a reaction that no one knew was possible and make it practical and useful in a very short time. This really speaks to the power of their overall method."

MacMillan conceived of accelerated serendipity after reflecting on his doctoral work at the University of California-Irvine during the 1990s. His work there hinged on two unforeseen yet important reactions that occurred in the span of six years, he said. When envisioning the project reported in Science, MacMillan calculated that if, in a single day, he ran the equivalent of one reaction per day for three years — nearly 1,100 reactions — the odds favored a new discovery, he said.

The Princeton team began running reactions once a day using a high-throughput, automated reaction accelerator in Princeton's Merck Center for Catalysis, combining on a one-to-one ratio molecules with no reported affect on each other.

Central to the process is a technique developed in MacMillan's lab and reported in Science in 2008 to synthesize chemical reactions using a low-power light source, such as a household light bulb. Known as photoredox catalysis, the reaction takes place when inorganic catalysts absorb light particles from the light source then pass an electron onto the organic molecules, which creates, or synthesizes, a new compound.

For the latest work, MacMillan and his team carried out this process on the molecules before each reaction cycle. Because the use of photoredox catalysts in organic-compound synthesis is relatively new — it has been typically used by chemists and in industry for processes such as energy storage and hydrogen production — it has not been as thoroughly explored as the more common method of using catalysts derived from metals such as nickel, gold and copper, MacMillan said. Thus, he said, elements with no history of reacting with each other could possibly produce results under this different approach.

"If one wanted to find new reactions, it would have to be done in a completely new area of chemistry research where the chances of finding something completely unknown are probably higher than continuing in an area that has been studied for the past 50 years," MacMillan said.

The Princeton researchers produced numerous new reactions, but "new" does not necessarily equal interesting or important, MacMillan said. They analyzed and experimented with each new reaction for its potential application, a process that revealed the nitrogen-carbon molecule with the aromatic ring.

An important feature of the Princeton researchers' molecule — like any important discovery — is that its application extends beyond the material itself, MacMillan said. He and his colleagues have begun mining the very process that created the molecule for indications that other novel reactions can be brought about.

"If we found this was one really valuable , we wondered what others exist that we just don't know about," MacMillan said.

"Another very valuable aspect of the molecule we created is that once we understood how it happened, it set us up to design other completely new reactions based upon our understanding of what happened initially," he said. "Now, we're applying similar techniques broadly, finding new reactions continually and determining which ones are important.

"To us that really proved the point of why you want serendipitous findings," MacMillan said. "They present new knowledge, and based upon that new knowledge you can invent."

Provided by Princeton University (news : web)

Just the two of us: Stable dinucleotide-RNA duplexes show promise in biotechnology

A Swedish team headed by R. Strömberg recently reported in the European Journal of Organic Chemistry that modification of oligonucleotides with a 2'-O-carbamoyl moiety greatly increases the stability of these compounds, which may render their use in constructs for biotechnological and therapeutic applications viable.

Efficiency in the regulation of gene expression is readily achieved if turnover of the target RNA is obtained, but this can only occur if native enzymes recognize the relevant oligonucleotide complex. The ability to catalytically cleave a specific sequence of RNA at a specific site is of high potential value in biotechnology and therapy. Thus, the development of oligonucleotide-based artificial nucleases (OBANs) as artificial enzymes capable of cleaving mRNA sequences arising from genetic or viral diseases is highly sought.

In this context, the scientists set out to modify oligonucleotides with the judicious choice of a 2'-carbamoylmethyl (CM) moiety. Substitution at the 2-position was an important prerequisite, as this has been shown to lead to the formation of stable duplexes with the target , and it was also believed that the CM moiety could further increase the stability of the duplex through hydrogen bonding.

The team was able to show that the 2'-O-carbamoyl modification substantially protected the dinucleotide against enzyme-catalyzed degradation by phosphodiesterase I and made it virtually resistant to degradation by phosphodiesterase II. This, together with the reported increased thermal stability of the duplexes, makes the often-neglected 2'-O-carbamoyl moiety an interesting modification in the pursuit of future compounds that may one day help in the treatment of .

More information: Roger Strömberg, Stability of a 2'-O-(Carbamoylmethyl)adenosine-Containing Dinucleotide, European Journal of Organic Chemistry, … oc.201101264

Provided by Wiley (news : web)