Nanoparticle assembly is like building with LEGOs

New processes that allow nanoparticles to assemble themselves into designer materials could solve some of today's technology challenges, Alex Travesset of Iowa State University and the Ames Laboratory reports in the Oct. 14 issue of the journal Science.

Travesset, an associate professor of physics and astronomy and an associate of the U.S. Department of Energy's Ames Laboratory, writes in the journal's Perspectives section that the controlled self-assembly of nanoparticles could help researchers create new materials with unique electrical, optical, mechanical or transport properties.

"Nanoparticle self-assembly has entered the LEGO era," Travesset said. "You can really work with nanoparticles in the same way you can work with LEGOs. This represents a breakthrough in the way we can manipulate matter. Really revolutionary applications will come."

In his commentary, Travesset reports on the ramifications of a scientific paper also published in the Oct. 14 issue of Science. Lead authors of the scientific paper are Chad Mirkin, director of the International Institute for Nanotechnology at Northwestern University in Evanston, Ill., and George Schatz, a professor of chemistry at Northwestern. Their research team describes new technologies that use complementary DNA strands to link nanoparticles and control how the particles precisely assemble into target structures.

Nanoparticles are so small -- just billionths of a meter -- that it is practically impossible to assemble real materials particle by particle. Past attempts to induce their self-assembly have been successful in only a handful of systems and in very restrictive conditions.

The developments by the Mirkin and Schatz research team are "likely to elevate DNA-programmed self-assembly into a technique for the design of nanoparticle structures a la carte," Travesset wrote.

Travesset's research program includes theoretical studies of the assembly of nanoparticles and how they can be uniformly mixed with polymers. A research paper describing some of his findings was published in the May 27 issue of the journal Physical Review Letters (Dynamics and Statics of DNA-Programmable Nanoparticle Self-Assembly and Crystallization).

With the development of efficient self-assembly technologies, Travesset said there's tremendous potential for nanoparticle science.

"Being able to assemble nanoparticles with such control represents a major accomplishment in our quest to manipulate matter," he wrote in Science. "There are immediate important applications related to catalysis, medical sensing, new optical materials or metamaterials, and others that will follow from these studies.

"Most likely, however, many other applications will arise as we dig deeper, understand better, expand further, and tinker with the opportunities provided by these materials."

Other bookmarking and sharing tools:

The above story is reprinted (with editorial adaptations ) from materials provided by Iowa State University.

Journal Reference:

Alex Travesset. Self-Assembly Enters the Design Era. Science, 2011; 334 (6053): 183-184 DOI: 10.1126/science.1213070

X-rays help advance the battle against heart disease

Scientists from Imperial College London and Diamond Light Source have revealed the structure of a cholesterol-lowering-drug target. Published in the journal Nature, this finding could lead to much more effective drugs to tackle high cholesterol levels, a condition that increases the risk of heart disease.

The researchers from Imperial College London used intense X-rays, generated by the Diamond synchrotron and the European Synchrotron Radiation Facility (ESRF), to determine for the first time the structure of bacterial homologue of the Apical Sodium dependent Bile Acid Transporter (ASBT) protein, a target for hypercholesterolemia drugs since it can affect the level of cholesterol in the blood.

Picture to the right shows a cartoon representation of the ASBTnm structure embedded in the membrane. The protein transports bile acids across the membrane. A bile acid has been trapped in a cavity on the inside face of the protein (shown in wine-red). Energy to drive the transport is provided by sodium ions. Two sodium ions are bound to the structure and these are shown as pink spheres.

In the liver, cholesterol makes bile acids which are used in the intestine to absorb fat. These bile acids are then reabsorbed by ASBT to be transported to the liver and recycled. It is known that by blocking ASBT, bile acid levels returning to the liver are lowered, the liver therefore converts more cholesterol into bile acids, which lowers the level of cholesterol in the blood.

“There are currently a number of existing ASBT inhibitors effective in animal models, which were developed without structural knowledge of the protein. Now that we know the shape and size of the drug-binding site within a bacterial model of the protein, this detailed structural information should enable the design of improved drugs which are much more targeted and will “fit” much better.” said Professor So Iwata, David Blow Chair of Biophysics at Imperial College London.

This new knowledge could have a wider impact on drug design. Dr Alexander Cameron from Imperial College London and the Membrane Protein Laboratory at Diamond explains: “As some drugs are poorly absorbed in the intestine or need to be targeted to the liver, ASBT has also received attention as a pro-drug carrier, capable of transporting various compounds coupled to bile acid. This means that there could be scope to improve a number of drugs tackling different problems, for example, cytostatic compounds targeting liver tumours.”

Picture to the left shows a surface representation of ASBTnm looking from the inside face of the membrane showing bile acid bound in a deep cavity.

Enlarge

ASBT is a membrane protein, one of over 7,000 within the human body, of which many are important drug targets. Over 50% of current commercially available drugs target membrane proteins but they are notoriously hard to crystallise – a step that is a pre-requisite in solving protein structures using a synchrotron. Dr David Drew, Royal Society Research Fellow in the Life Sciences Department at Imperial College London said: “Key to the success was to find a suitable detergent that yielded good protein crystals, this arduous task was facilitated greatly by a large-scale stability screen we carried out."

The ESRF and Diamond Light Source were essential to screen their crystals and collect the data used to obtain the structure. At Diamond they were also able to access specialised equipment that dehydrates the crystals, improving the resolution of their diffraction data, thus leading to much more accurate results.

“Since membrane proteins are so hard to crystallise, you have to make sure that you try everything possible to improve the quality of data you can extract from each crystal. I am very pleased that the technical effort we have put into this development has resulted in some great scientific results. We will continue to integrate this equipment to help our users with new, challenging projects.” said Dr Juan Sanchez-Weatherby, who played a key role in the development of the crystal dehydration equipment.

More information: ‘Crystal structure of a bacterial homologue of the bile acid sodium symporter ASBT’ Nien-Jen Hu, So Iwata, Alexander D. Cameron, David Drew
DOI: 10.1038/nature10450

Provided by Diamond Light Source

Polymeric material has potential for noninvasive procedures

Scientists at the University of California, San Diego have developed what they believe to be the first polymeric material that is sensitive to biologically benign levels of near infrared (NRI) irradiation, enabling the material to disassemble in a highly controlled fashion. The study represents a significant milestone in the area of light-sensitive material for non-invasive medical and biological applications. Their work is published on line this week in the journal Macromolecules.

"To the best of our knowledge, this is the only polymeric material specifically designed to break down in to small fragments in response to very low levels of NIR irradiation," said Adah Almutairi, PhD, assistant professor at the UCSD Skaggs School of Pharmacy and Pharmaceutical Sciences and director of the Laboratory of Bioresponsive Materials at UC San Diego. "The material was also shown to be well-tolerated in cells before and after irradiation. We think there is great potential for use in human patients, allowing previously inaccessible targets sites to be reached for both treatment and diagnosis."

The properties of so-called "smart" polymeric materials – either synthetic or natural – respond readily to small changes in their environment. They are, therefore, the focus of widespread research to develop tools for such uses as tissue engineering, implants, wound-healing, drug delivery and biosensors.

NIR light can penetrate up to 10 cm into tissue with less damage, absorption and scattering than visible light, and can be remotely applied with high spatial and temporal precision. Most other light-degradable materials that have been developed to date can be difficult to clear from the body, and only a handful of organic materials respond to high-power NIR light. Until now, none were able to respond to low-level, thus safer, NIR light – which causes less photodamage to tissue and cells.

The UC San Diego researchers stated that further studies are warranted to improve the sensitivity of these smart polymeric materials to NIR, and they are currently pursuing several synthetic and engineering strategies to improve design of such biomaterials.

Provided by University of California - San Diego (news : web)

Glucosamine-like supplement suppresses multiple sclerosis attacks

A glucosamine-like dietary supplement suppresses the damaging autoimmune response seen in multiple sclerosis, according to a UC Irvine study.

UCI's Dr. Michael Demetriou, Ani Grigorian and others found that oral N-acetylglucosamine (GlcNAc), which is similar to but more effective than the widely available glucosamine, inhibited the growth and function of abnormal T-cells that in MS incorrectly direct the immune system to attack and break down central nervous system tissue that insulates nerves.

Study results appear online in The Journal of Biological Chemistry.

Earlier this year, Demetriou and colleagues discovered that environmental and inherited risk factors associated with MS – previously poorly understood and not known to be connected – converge to affect how specific sugars are added to proteins regulating the disease.

"This sugar-based supplement corrects a genetic defect that induces cells to attack the body in MS," said Demetriou, associate professor of neurology and microbiology & molecular genetics, "making metabolic therapy a rational approach that differs significantly from currently available treatments."

Virtually all proteins on the surface of cells, including immune cells such as T-cells, are modified by complex sugar molecules of variable sizes and composition. Recent studies have linked changes in these sugars to T-cell hyperactivity and autoimmune disease.

In mouse models of MS-like autoimmune disease, Demetriou and his team found that GlcNAc given orally to those with leg weakness suppressed T-cell hyperactivity and autoimmune response by increasing sugar modifications to the T-cell proteins, thereby reversing the progression to paralysis.

The study comes on the heels of others showing the potential of GlcNAc in humans. One reported that eight of 12 children with treatment-resistant autoimmune inflammatory bowel disease improved significantly after two years of GlcNAc therapy. No serious adverse side effects were noted.

"Together, these findings identify metabolic therapy using dietary supplements such as GlcNAc as a possible treatment for autoimmune diseases," said Demetriou, associate director of UCI's Multiple Sclerosis Research Center. "Excitement about this strategy stems from the novel mechanism for affecting T-cell function and autoimmunity – the targeting of a molecular defect promoting disease – and its availability and simplicity."

He cautioned that more human studies are required to assess the full potential of the approach. GlcNAc supplements are available over the counter and differ from commercially popular glucosamine. People who purchase GlcNAc should consult with their doctors before use.

Provided by University of California - Irvine

Colorful leaves: New chlorophyll decomposition product found in Norway maple

 Autumn is right around the corner in the northern hemisphere and the leaves are beginning to change color. The cause of this wonderful display of reds, yellows, and oranges is the decomposition of the compound that makes leaves green: chlorophyll.

Bernhard Kräutler and a team at the University of Innsbruck (Austria) have now published a report in the journal Angewandte Chemie about the discovery of a previously unknown chlorophyll decomposition product in the leaves of Norway maples. The different spatial arrangement of its atoms is indicative of a different decomposition pathway than those of other deciduous trees.

During the summer months, green leaves carry out photosynthesis: chlorophyll converts sunlight into chemical energy. In the fall, deciduous trees reabsorb critical nutrients, such as nitrogen and minerals, from their leaves. This releases the chlorophyll from the proteins that normally bind it. However, chlorophyll is phototoxic in this free from, and can damage the tree when exposed to light. It must therefore be “detoxified” by decomposition.

“Essential pieces of the puzzle of this biological phenomenon have been solved only within the last two decades,” reports Kräutler. Various colorless tetrapyrroles, molecules with a framework of four nitrogen-containing five-membered carbon rings, accumulate in the dying leaves of higher plants, and have been classified as decomposition products of chlorophyll. These are called “nonfluorescent” chlorophyll catabolytes (NCCs). Says Kräutler, “ they are considered to be the final breakdown products of a well-controlled, “linear” and widely common decomposition pathway.” This premise is beginning to get a little shaky.

Kräutler and his co-workers have studied the decomposition of chlorophyll in the Norway maple, a tree native to Eurasia. “We found none of the typical breakdown products in yellow-green or yellow Norway maple leaves,” says Kräuter. “Instead, the main product we found was a dioxobilane, which resembles a chlorophyll breakdown product found in barley leaves.”

However, there are small but important differences in the spatial arrangements of the atoms relative to each other. There is no plausible decomposition pathway that starts with the NCCs and leads to this new decomposition product. “There is clearly a chlorophyll breakdown pathway occurring in Norway maple leaves that differs from those previously known.”

The structure of this newly discovered dioxobilane is reminiscent of bile pigments, which are products of the breakdown of heme, and thus are important constituents of mammalian metabolisms as well as acting as light sensors in plants. “This supports the idea that chlorophyll breakdown is not only a detoxification process; the resulting decomposition products can also play a physiological role,” states Kräuter. “Chlorophyll breakdown products can act as antioxidants in the peel of ripening fruits, making the fruits less perishable. What role they play in leaves is not yet clear.”

More information: A Dioxobilane as Product of a Divergent Path of Chlorophyll Breakdown in Norway Maple, Angewandte Chemie International Edition, http://dx.doi.org/ … ie.201103934

Provided by Wiley (news : web)

Nuclear receptors battle it out during metamorphosis in new fruit fly model

Growing up just got more complicated. Thomas Jefferson University biochemistry researchers have shown for the first time that the receptor for a major insect molting hormone doesn't activate and repress genes as once thought. In fact, it only activates genes, and it is out-competed by a heme-binding receptor to repress the same genes during the larval to pupal transition in the fruit fly.

For the last 20 years, the nuclear receptor known as EcR/Usp was thought to solely control gene transcription depending on the presence or absence of the hormone ecdysone, respectively. But it appears, researchers found, that E75A, a heme-binding receptor that represses genes, replaces EcR/Usp during metamorphosis when ecdysone is absent.

The findings, which could shed light on new ways to better understand and treat hormone-dependent diseases, such as cancer, were published in the online October 6 issue of Molecular Cell.

"This is the first time we've shown that a steroid hormone receptor and heme-binding nuclear receptor are even interacting with each other," said Danika M. Johnston, Ph.D. "We didn't really think the two were competing against each other to bind to the same sequence of DNA and regulate the same genes."

More specifically, in the absence of ecdysone, both ecdysone receptor subunits localize to the cytoplasm, and the heme-binding nuclear receptor E75A replaces EcR/Usp at common target sequences in several genes. During the larval-pupal transition, a switch from gene activation by EcR/Usp to gene repression by E75A is triggered by a decrease in ecdysone concentration and by direct repression of the EcR gene by E75A.

An important nuance of this system is that the heme-binder E75A is sensitive to the amount of nitric oxide in the cell, and it cannot completely fulfill its repressive potential at high levels of this important molecule. Thus, the uncovered system uses changing amounts of two ligands, a steroid hormone and a gas, to regulate transcription during development.

"These were quite unexpected findings, given the longstanding thoughts of this process," said Dr. Johnston, "but we just didn't have the tools in the past to figure out what was going on mechanistically. We're painting a clearer picture now."

Knowing how nuclear receptors regulate gene expression in animal models can provide useful information in the development of drugs. Today, the molecular targets of roughly 13 percent of U.S. Food and Drug Administration approved drugs are nuclear receptors.

"It's very possible that similar situations exist in the mammalian system. That could ultimately lead to different treatments that regulate hormone levels in hormone-dependent diseases, such as cancer," said Dr. Johnston.

Provided by Thomas Jefferson University (news : web)

Israeli wins chemistry Nobel for quasicrystals (Update 3)

 

Israeli scientist Dan Shechtman was awarded the Nobel Prize in chemistry on Wednesday for a discovery that faced skepticism and mockery, even prompting his expulsion from his U.S. research team, before it won widespread acceptance as a fundamental breakthrough.

When Israeli scientist Dan Shechtman claimed to have stumbled upon a new crystalline chemical structure that seemed to violate the laws of nature, colleagues mocked him, insulted him and exiled him from his research group.

After years in the scientific wilderness, though, he was proved right. And on Wednesday, he received the ultimate vindication: the Nobel Prize in chemistry.

The lesson?

"A good scientist is a humble and listening scientist and not one that is sure 100 percent in what he read in the textbooks," Shechtman said.

The shy, 70-year-old Shechtman said he never doubted his findings and considered himself merely the latest in a long line of scientists who advanced their fields by challenging the conventional wisdom and were shunned by the establishment because of it.

In 1982, Shechtman discovered what are now called "quasicrystals" - atoms arranged in patterns that seemed forbidden by nature.

"I was thrown out of my research group. They said I brought shame on them with what I was saying," he recalled. "I never took it personally. I knew I was right and they were wrong."

The discovery "fundamentally altered how chemists conceive of solid matter," the Royal Swedish Academy of Sciences said in awarding the $1.5 million prize.

Since his discovery, quasicrystals have been produced in laboratories, and a Swedish company found them in one of the most durable kinds of steel, which is now used in products such as razor blades and thin needles made specifically for eye surgery, the academy said. Quasicrystals are also being studied for use in new materials that convert heat to electricity.

Shechtman is a professor at the Technion-Israel Institute of Technology in Haifa, Israel. He is the 10th Israeli Nobel winner, a great source of pride in a nation of just 7.8 million people. Shechtman fielded congratulatory calls from Israeli President Shimon Peres, who shared the Nobel Peace Prize in 1994, and Prime Minister Benjamin Netanyahu.

"Every citizen of Israel is happy today and every Jew in the world is proud," Netanyahu said.

Staffan Normark, permanent secretary of the Royal Swedish Academy, said Shechtman's discovery was one of the few Nobel Prize-winning achievements that can be dated to a single day.

On April 8, 1982, while on sabbatical at the National Bureau of Standards in Washington - now called the National Institute of Standards and Technology - Shechtman first observed crystals with a shape most scientists considered impossible.

The discovery had to do with the idea that a crystal shape can be rotated a certain amount and still look the same. A square contains four-fold symmetry, for example: If you turn it by 90 degrees, a quarter-turn, it still looks the same. For crystals, only certain degrees of such symmetry were thought possible. Shechtman had found a crystal that could be rotated one-fifth of a full turn and still look the same.

"I told everyone who was ready to listen that I had material with pentagonal symmetry. People just laughed at me," he said in an account released by his university.

He was asked to leave his research group, and moved to another one within the National Bureau of Standards, Shechtman said. He eventually returned to Israel, where he found one colleague prepared to work with him on an article describing the phenomenon. The article was at first rejected but was finally published in November 1984 to an uproar in the scientific world.

In 1987, friends in France and Japan succeeded in growing crystals large enough for X-rays to verify what he had discovered with the electron microscope.

"The moment I presented that, the community said, `OK, Danny, now you are talking. Now we understand you. Now we accept what you have found,'" Shechtman told reporters.

Shechtman, who also teaches at Iowa State University in Ames, Iowa, said he never wavered even in the face of stiff criticism from double Nobel winner Linus Pauling, who never accepted Shechtman's findings.

"He would stand on those platforms and declare, 'Danny Shechtman is talking nonsense. There is no such thing as quasicrystals, only quasi-scientists.'" Shechtman said. "He really was a great scientist, but he was wrong. It's not the first time he was wrong."

Shechtman's battle "eventually forced scientists to reconsider their conception of the very nature of matter," the academy said.

Nancy B. Jackson, president of the American Chemical Society, called Shechtman's breakthrough "one of these great scientific discoveries that go against the rules." Only later did some scientists go back to some of their own inexplicable findings and realize they had seen quasicrystals without understanding what were looking at, Jackson said.

"Anytime you have a discovery that changes the conventional wisdom that's 200 years old, that's something that's really remarkable," said Princeton University physicist Paul J. Steinhardt, who coined the term "quasicrystals" and had been doing theoretical work on them before Shechtman reported finding the real thing.

Steinhardt recalled the day a fellow scientist showed him Shechtman's paper in 1984: "I sort of leapt in the air."

More information: http://www.nobelpr … reates/2011/

For advanced information: http://www.nobelpr … ack_2011.pdf

A remarkable mosaic of atoms

In quasicrystals, we find the fascinating mosaics of the Arabic world reproduced at the level of atoms: regular patterns that never repeat themselves. However, the configuration found in quasicrystals was considered impossible, and Daniel Shechtman had to fight a fierce battle against established science. The Nobel Prize in Chemistry 2011 has fundamentally altered how chemists conceive of solid matter.

On the morning of 8 April 1982, an image counter to the laws of nature appeared in Daniel Shechtman's electron microscope. In all solid matter, atoms were believed to be packed inside crystals in symmetrical patterns that were repeated periodically over and over again. For scientists, this repetition was required in order to obtain a crystal.

Shechtman's image, however, showed that the atoms in his crystal were packed in a pattern that could not be repeated. Such a pattern was considered just as impossible as creating a football using only six-cornered polygons, when a sphere needs both five- and six-cornered polygons. His discovery was extremely controversial. In the course of defending his findings, he was asked to leave his research group. However, his battle eventually forced scientists to reconsider their conception of the very nature of matter.

Aperiodic mosaics, such as those found in the medieval Islamic mosaics of the Alhambra Palace in Spain and the Darb-i Imam Shrine in Iran, have helped scientists understand what quasicrystals look like at the atomic level. In those mosaics, as in quasicrystals, the patterns are regular - they follow mathematical rules - but they never repeat themselves.

When scientists describe Shechtman's quasicrystals, they use a concept that comes from mathematics and art: the golden ratio. This number had already caught the interest of mathematicians in Ancient Greece, as it often appeared in geometry. In quasicrystals, for instance, the ratio of various distances between atoms is related to the golden mean.

Following Shechtman's discovery, scientists have produced other kinds of quasicrystals in the lab and discovered naturally occurring quasicrystals in mineral samples from a Russian river. A Swedish company has also found quasicrystals in a certain form of steel, where the crystals reinforce the material like armor. Scientists are currently experimenting with using quasicrystals in different products such as frying pans and diesel engines.

?2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

'Perfect plastic' created

Researchers at the University of Leeds and Durham University have solved a long-standing problem that could revolutionize the way new plastics are developed.

The breakthrough will allow experts to create the 'perfect plastic' with specific uses and properties by using a high-tech 'recipe book.' It will also increase our ability to recycle plastics. The research paper is published in the prestigious journal Science on Thursday.

The paper's authors form part of the Microscale Polymer Processing project, a collaboration between academics and industry experts which has spent 10 years exploring how to better build giant 'macromolecules.' These long tangled molecules are the basic components of plastics and dictate their properties during the melting, flowing and forming processes in plastics production.

Low-density polyethylenes (LDPEs) are used in trays and containers, lightweight car parts, recyclable packaging and electrical goods. Up until now, industry developed a plastic then found a use for it, or tried hundreds of different "recipes" to see which worked. This method could save the manufacturing industry time, energy and money.

The mathematical models used put together two pieces of computer code. The first predicts how polymers will flow based on the connections between the string-like molecules they are made from. A second piece of code predicts the shapes that these molecules will take when they are created at a chemical level. These models were enhanced by experiments on carefully synthesised 'perfect polymers' created in labs of the Microscale Polymer Processing project.

Dr. Daniel Read, from the School of Mathematics, University of Leeds, who led the research, said, "Plastics are used by everybody, every day, but until now their production has been effectively guesswork. This breakthrough means that new plastics can be created more efficiently and with a specific use in mind, with benefits to industry and the environment."

Professor Tom McLeish, formerly of the University of Leeds, now Pro-Vice Chancellor for Research at Durham University leads the Microscale Polymer Processing project. He said, "After years of trying different chemical recipes and finding only a very few provide useable products, this new science provides industry with a toolkit to bring new materials to market faster and more efficiently."

Professor McLeish added that as plastics production moves from oil-based materials to sustainable and renewable materials, the "trial and error" phase in developing new plastics could now be by-passed. He said, "By changing two or three numbers in the computer code, we can adapt all the predictions for new bio-polymer sources."

"This is a wonderful outcome of years of work by this extraordinary team. It's a testimony to the strong collaborative ethos of the UK research groups and global companies involved," he added.

Dr. Ian Robinson of Lucite International, one of the industrial participants in the wider project said, "The insights offered by this approach are comparable to cracking a plastics 'DNA.'"

The model was developed by Dr. Daniel Read, School of Mathematics, University of Leeds, Dr. Chinmay Das of the School of Physics & Astronomy, University of Leeds and Professor Tom McLeish, Department of Physics, Durham University. Their predictions were compared to the results of polymer analysis by Dr. Dietmar Auhl, at the time a physicist at Leeds.

Provided by University of Leeds (news : web)

'Genetic biopsy' of human eggs might help pick the best for IVF

Given the stakes of in vitro fertilization, prospective parents and their doctors need the best information they can get about the eggs they will extract, attempt to fertilize, and implant. New research at Brown University and Women & Infants Hospital of Rhode Island has found a way to see which genes each egg cell is expressing without harming it. As researchers learn more about how those genes affect embryo development, the new technique could ultimately give parents and doctors a preview of which eggs are likely to make the most viable embryos.

In the research, now in press in the Journal of Biological Chemistry, the team of physicians and biologists were able to sequence the transcribed genetic material, or mRNA, in egg cells and, in a scientific first, in smaller structures pinched off from them called "polar bodies." By comparing the gene expression sequences in polar bodies and their host eggs, the researchers were able to determine that the polar bodies offer a faithful reflection of the eggs' genetic activity.

"We can now consider the polar body a natural cytoplasmic biopsy," said study co-author Sandra Carson, professor obstetrics and gynecology at the Warren Alpert Medical School of Brown University and director of the Center for Reproduction and Infertility at Women & Infants Hospital.

Polar bodies are where egg cells dispense with the second copies of chromosomes that, as sex cells, they don't need. But the polar bodies also capture a microcosm of the egg's mRNA, the genetic material produced when genes have been transcribed and a cell is set to make proteins based on those genetic instructions.

Pairs of genes

Last year the team became the first to find mRNA in human polar bodies. Now they have transcribed it in 22 pairs of human eggs and their polar bodies, and confirmed that what is in the polar bodies is a good proxy for what is in the eggs.

Given how little mRNA is present in polar bodies, the task was not easy, said Gary Wessel, professor of biology, but through a combination of clever amplification and analysis techniques by lead author and graduate student Adrian Reich and second author Peter Klatsky, the team got it done.

"There's no reason this should have worked, just because there was so little material," Wessel said. "Single-cell sequencing is very challenging."

To hedge their bets the team analyzed most of their samples in two pools of 10 cells each, for instance comparing the mRNA in 10 eggs with the mRNA in the 10 related polar bodies. But to their pleasant surprise, they were also able to sequence two individual eggs and their polar bodies directly.

What they found is that more than 14,000 genes can be expressed in the eggs. Of those, more than 90 percent of the genes detected in the polar bodies were also detected in the eggs and of the 700 most abundant genes found in the polar bodies, 460 were also among the most abundant in the eggs.

Toward clinical use

"It seems that the polar body does reflect what is in the egg," Carson said. "Because the egg is the major driver of the first three days of human embryo development, what we find in the polar body may give us a clue into what is happening during that time."

But Carson and Wessel acknowledged that more research will be required to create a clinically useful tool.

Finding which genes affect embryo viability is the next major step. With the new knowledge and techniques developed in their study, the researchers said, scientists could analyze the mRNA from polar bodies of eggs that are fertilized and track the progress of the resulting embryos. Once the key genes are known, they could create fast assays to look for those genes in polar bodies so that clinicians and patients could pick the best eggs. A sufficiently developed technology could also be used for choosing which eggs to bank for later use.

"We don't quite have the answer of what those messages are doing exactly or necessarily the purpose of them in the cell function, but that's to come," Carson said. "Now we have the words, but not the sentences."

Provided by Brown University (news : web)

Researchers watch amyloid plaques form

Researchers at the University of Toronto Scarborough (UTSC) and Osaka University applied a new approach to take a close look at amyloid plaque formation, a process that plays important roles in Alzheimer's disease. The technique would greatly aid the development and screening for novel therapeutics that can manipulate the formation of the toxic amyloid aggregates.

Anthony Veloso, Prof. Kagan Kerman's PhD student in Chemistry, used a laser to trap amyloid-beta peptides and examined them under a fluorescence microscope as they aggregate, giving them an exceptionally detailed view of the process. The work appears on the cover of the current issue of Analyst, a journal of the Royal Society of Chemistry.

"This technique could accelerate the drug discovery process. It gives us a new way to examine the early phase of plaque formation, when the most toxic species of oligomers are formed," says Prof. Kerman, a faculty with the Department of Physical and Environmental Sciences at UTSC and the corresponding author on the paper.

Amyloid plaques are protein deposits that form around neurons and interfere with their function. The major constituent of these deposits are amyloid-beta, a peptide that clumps together to form harmful plaques in Alzheimer's patients, but is otherwise harmless in normal individuals.

To get a look at the early stages of the process, the Canadian researchers and their Japanese collaborators used a technique called optical trapping. A laser is focused into a very thin beam and aimed at solution containing amyloid-beta particles. The beam creates a small magnetic field, which attracts and holds the particles in place. Amyloid aggregates stained by a dye then glows under the laser light, and the image can be captured by fluorescence microscope.

By using this technique, A. Veloso and Prof. Kerman hope to explore how the aggregates are formed, and to eventually discover the role of amyloid aggregates in Alzheimer's disease. Utilizing the versatility of this technique, Prof. Kerman's research team can extend their studies to understand aggregate formation in other neurodegenerative diseases.

The technique will also become a novel strategy to test therapeutic compounds that could halt the formation of plaques. Prof. Kerman and A. Veloso are working towards the automation of the technique, allowing for many compounds to be tested efficiently.

Provided by University of Toronto Scarborough

New membrane lipid measuring technique may help fight disease

Could controlling cell-membrane fat play a key role in turning off disease?

Researchers at the University of Illinois at Chicago think so, and a biosensor they've created that measures membrane lipid levels may open up new pathways to disease treatment.

Wonhwa Cho, distinguished professor of chemistry, and his coworkers engineered a way to modify proteins to fluoresce and act as sensors for lipid levels.

Their findings are reported in Nature Chemistry, online on Oct. 9.

"Lipid molecules on cell membranes can act as switches that turn on or off protein-protein interactions affecting all cellular processes, including those associated with disease," says Cho. "While the exact mechanism is still unknown, our hypothesis is that lipid molecules serve sort of like a sliding switch."

Cho said once lipid concentrations reach a certain threshold, they trigger reactions, including disease-fighting immune responses. Quantifying lipid membrane concentration in a living cell and studying its location in real time can provide a powerful tool for understanding and developing new ways to combat a range of maladies from inflammation, cancer and diabetes to metabolic diseases.

"It's not just the presence of lipid, but the number of lipid molecules that are important for turning on and off biological activity," said Cho.

While visualizing lipid molecules with fluorescent proteins isn't new, Cho's technique allows quantification by using a hybrid protein molecule that fluoresces only when it binds specific lipids. His lab worked with a lipid known as PIP2 -- an important fat molecule involved in many cellular processes. Cho's sensor binds to PIP2 and gives a clear signal that can be quantified through a fluorescent microscope.

The result is the first successful quantification of membrane lipids in a living cell in real time.

"We had to engineer the protein in such a way to make it very stable, behave well, and specifically recognizes a particular lipid," Cho said. He has been working on the technique for about a decade, overcoming technical obstacles only about three years ago.

Cho hopes now to create a tool kit of biosensors to quantify most, if not all lipids.

"We'd like to be able to measure multiple lipids, simultaneously," he said. "It would give us a snapshot of all the processes being regulated by the different lipids inside a cell."

Provided by University of Illinois at Chicago (news : web)

Perspective article examines conductivity at the LaAlO3 and SrTiO3 (001) interface

Complex oxides have the potential to inject new functionalities into technologies that require semiconductors.  The correlated behavior of itinerant electrons in these materials sets complex oxides apart from traditional semiconductors such as Si and GaAs. Potential applications abound, but the fundamental properties of these materials, particularly when combined to make interfaces, must be understood.  In an invited Perspective article in Surface Science, Dr. Scott Chambers of PNNL examines conductivity at the interface of polar and nonpolar complex oxides from outside the reigning paradigm and considers how unintentional dopants and defects, resulting from interfacial mixing, might affect the electronic properties.

The common paradigm used to explain the observation of conductivity at interfaces of materials such as lanthanum aluminate and strontium titanate is that electrons move across the interface to alleviate the so-called polar catastrophe created by polar/nonpolar interface creation.  Based on a number of different experimental results, Chambers argues that this simple paradigm is inadequate to explain observed conductivity.

"Intermixing occurs, and the resulting cation rearrangement cannot be ignored," said Chambers, a Fellow of the AVS and the American Association for the Advancement of Science. "Moreover, defects and dopants appear to play a role in facilitating, if not enabling conductivity."

Providing insights into the fundamental relationships between composition/structure, and the resulting electronic, magnetic, and surface chemical properties of complex oxides could enable these materials to have an impact on next-generation electronics, chemical sensors, and photocatalysts. These advances could include more energy-efficient field effect transistors and photocatalysts that use visible light from the sun.

Chambers and his colleagues around the world are continuing to make strides in understanding the complex relationships between atom distributions near the interface and conductivity. One upshot is that significantly more insight into the growth process is necessary to characterize and ultimately control defect creation during heterojunction formation.

"Then and only then can interface structures suspected of facilitating conductivity be changed to see if doing so actually reduces or eliminates conductivity," said Chambers.

More information: Chambers SA. 2011. "Understanding the Mechanism of Conductivity at the LaAlO3 and SrTiO3 (001) Interface." Surface Science 605:1133-1140.

Provided by Pacific Northwest National Laboratory (news : web)

Building better catalysts: Chemists find new way to design important molecules

University of Utah chemists developed a method to design and test new catalysts, which are substances that speed chemical reactions and are crucial for producing energy, chemicals and industrial products. By using the new method, the chemists also made a discovery that will make it easier to design future catalysts.

The discovery: the sizes and electronic properties of catalysts interact to affect how well a catalyst performs, and are not independent factors as was thought previously. Chemistry Professor Matt Sigman and doctoral student Kaid Harper, report their findings in the Friday, Sept. 30, 2011, issue of the journal Science.

“It opens our eyes to how to design new catalysts that we wouldn’t necessarily think about designing, for a broad range of reactions,” Sigman says. “We’re pretty excited.”

Sigman believes the new technique for designing and testing catalysts “is going to be picked up pretty fast,” first by academic and then by industrial chemists, who “will see it’s a simple way to rapidly design better catalysts.”

The new study was funded by the National Science Foundation.

‘Catalysts Make the World Go ‘Round’

Catalysts speed chemical reactions without being consumed by those reactions. Their importance to society and the economy is tough to overstate. Products made with catalysts include medicines, fuels, foods and fertilizers.

Ninety percent of U.S. chemical manufacturing processes involve catalysts, which also are used to make more than one-fifth of all industrial products. Those processes consume much energy, so making catalytic reactions more efficient would both save energy and reduce emissions of climate-warming carbon dioxide gas.

“Catalysts make the world go ‘round,” says Sigman. “Catalysts are how we make molecules more efficiently and, more important, make molecules that can’t be made using any other method.”

The Utah researchers developed a new method for rapidly identifying and designing what are known as “asymmetric catalysts,” which are catalyst molecules that are considered either left-handed or right-handed because they are physically asymmetrical. In chemistry, this property of handedness is known as chirality.

Chemists want new asymmetric catalysts because they impart handedness or chirality to the molecules they are used to make. For example, when a left-handed or right-handed catalyst is used to speed a chemical reaction, the chemical that results from that reaction can be either left-handed or right-handed.

“Handedness is an essential component of a drug’s effectiveness,” Sigman says.

Drugs generally work by latching onto proteins involved in a disease-causing process. The drug is like a key that fits into a protein lock, and chirality “is the direction the key goes” to fit properly and open the lock, says Sigman.

“However, developing asymmetric catalysts [to produce asymmetric drug molecules] can be a time-consuming and sometimes unsuccessful undertaking” because it usually is done by trial and error, he adds.

Sigman says the new study “is a step toward developing faster methods to identify optimal catalysts and insight into how to design them.”

A Mathematical Approach to Catalyst Design

Harper and Sigman combined principles of data analysis with principles of catalyst design to create a “library” of nine related catalysts that they hypothesized would effectively catalyze a given reaction – one that could be useful for making new pharmaceuticals. Essentially, they used math to find the optimal size and electronic properties of the candidate catalysts.

Then the chemists tested the nine catalysts – known as “quinoline proline ligands” – to determine how well their degree of handedness would be passed on to the chemical reaction products the catalysts were used to produce.

Sigman and Harper depicted results of the reactions using the different catalysts as a three-dimensional mathematical surface that bulges upward. The highest part of the bulge represents those among the nine catalysts that had the greatest degree of handedness.

This technique was used – and can be used in the future – to identify the optimal catalysts among a number of candidates. But it also revealed the unexpected link between the size and electronic properties of catalysts in determining their effectiveness in speeding reactions.

“This study shows quantitatively that the two factors are related,” and knowing that will make it easier to design many future catalysts, Sigman says.

Provided by University of Utah (news : web)

Pressurized vascular systems for self-healing materials

Artificial microvascular systems for self-repair of materials damage, such as cracks in a coating applied to a building or bridge, have relied on capillary force for transport of the healing agents. Now, researchers at the University of Illinois' Beckman Institute have demonstrated that an active pumping capability for pressurized delivery of liquid healing agents in microvascular systems significantly improves the degree of healing compared with capillary force methods.

In a paper for the Royal Society journal Interface, Nancy Sottos, Scott White, and former graduate student Andrew Hamilton report on their investigation into using an active pumping method for microvascular systems in a paper titled Pressurized vascular systems for self-healing materials. Their inspiration, they write, comes from the fact that nature in its wisdom gives that ability to many biological systems: "Fluid flow in these natural vascular systems is typically driven by a pressure gradient induced by the pumping action of a heart, even in primitive invertebrates such as earthworms."

Sottos and White, faculty in the College of Engineering at the University of Illinois, and their fellow collaborators from Beckman, have developed different methods for self-healing, including microvascular systems for self-repair of polymers. The vascular system works when reactive fluids are released in response to stress, enabling polymerization that restores mechanical integrity.

For this project, Sottos, White, and Hamilton sought to determine the effectiveness of an active pumping mechanism in a microvascular system because, they wrote, relying on capillary flow to disperse the healing agents, "limits the size of healable damage," and because "unpressurized delivery of healing agents requires diffusional mixing -- a relatively slow and highly localized process for typical resin-hardener systems -- to occur for the healing reaction to initiate."

To achieve active pumping the researchers experimented with an external "pump" composed of two computer-controlled pressure boxes that allowed for more precise control over flow. The healing agents in the pump were fed into two parallel micro-channels. They found that active pumping improves the degree of mechanical recovery, and that a continuous flow of healing agents from dynamic pumping extends the repeatability of the self-healing response.

"Significant improvements," they write, "are achieved in the degree of healing and the number of healing events possible, compared with prior passive schemes that utilize only capillary forces for the delivery of healing agents."

Sottos said the study was a first step toward integrating active pumping into microvascular systems.

"This set-up could be used with any microvascular network, including the structural composites reported on recently," Sottos said. "In future materials, it would be ideal to have the pumping integrated in the materials itself.

"The advance of this paper is the study of active pumping/mixing for healing. We haven't applied this to healing with the structural composites yet; the present study was essential to understand what happens when we pump the healing agents."

Provided by Beckman Institute for Advanced Science and Technology

'Artificial leaf' makes fuel from sunlight (w/ video)

Researchers led by MIT professor Daniel Nocera have produced something they’re calling an “artificial leaf”: Like living leaves, the device can turn the energy of sunlight directly into a chemical fuel that can be stored and used later as an energy source.

The artificial leaf — a silicon solar cell with different catalytic materials bonded onto its two sides — needs no external wires or control circuits to operate. Simply placed in a container of water and exposed to sunlight, it quickly begins to generate streams of bubbles: oxygen bubbles from one side and hydrogen bubbles from the other. If placed in a container that has a barrier to separate the two sides, the two streams of bubbles can be collected and stored, and used later to deliver power: for example, by feeding them into a fuel cell that combines them once again into water while delivering an electric current.

The creation of the device is described in a paper published Sept. 30 in the journal Science. Nocera, the Henry Dreyfus Professor of Energy and professor of chemistry at MIT, is the senior author; the paper was co-authored by his former student Steven Reece PhD ’07 (who now works at Sun Catalytix, a company started by Nocera to commercialize his solar-energy inventions), along with five other researchers from Sun Catalytix and MIT.

The device, Nocera explains, is made entirely of earth-abundant, inexpensive materials — mostly silicon, cobalt and nickel — and works in ordinary water. Other attempts to produce devices that could use sunlight to split water have relied on corrosive solutions or on relatively rare and expensive materials such as platinum.

The artificial leaf is a thin sheet of semiconducting silicon — the material most solar cells are made of — which turns the energy of sunlight into a flow of wireless electricity within the sheet. Bound onto the silicon is a layer of a cobalt-based catalyst, which releases oxygen, a material whose potential for generating fuel from sunlight was discovered by Nocera and his co-authors in 2008. The other side of the silicon sheet is coated with a layer of a nickel-molybdenum-zinc alloy, which releases hydrogen from the water molecules.

This video is not supported by your browser at this time.

An 'artificial leaf' made by Daniel Nocera and his team, using a silicon solar cell with novel catalyst materials bonded to its two sides, is shown in a container of water with light (simulating sunlight) shining on it. The light generates a flow of electricity that causes the water molecules, with the help of the catalysts, to split into oxygen and hydrogen, which bubble up from the two surfaces.Video courtesy of the Nocera Lab/Sun Catalytix

“I think there’s going to be real opportunities for this idea,” Nocera says. “You can’t get more portable — you don’t need wires, it’s lightweight,” and it doesn’t require much in the way of additional equipment, other than a way of catching and storing the gases that bubble off. “You just drop it in a glass of water, and it starts splitting it,” he says.

Now that the “leaf” has been demonstrated, Nocera suggests one possible further development: tiny particles made of these materials that can split water molecules when placed in sunlight — making them more like photosynthetic algae than leaves. The advantage of that, he says, is that the small particles would have much more surface area exposed to sunlight and the water, allowing them to harness the sun’s energy more efficiently. (On the other hand, engineering a system to separate and collect the two gases would be more complicated in such a setup.)

The new device is not yet ready for commercial production, since systems to collect, store and use the gases remain to be developed. “It’s a step,” Nocera says. “It’s heading in the right direction.”

Ultimately, he sees a future in which individual homes could be equipped with solar-collection systems based on this principle: Panels on the roof could use sunlight to produce hydrogen and oxygen that would be stored in tanks, and then fed to a fuel cell whenever electricity is needed. Such systems, Nocera hopes, could be made simple and inexpensive enough so that they could be widely adopted throughout the world, including many areas that do not presently have access to reliable sources of electricity.

Professor James Barber, a biochemist from Imperial College London who was not involved in this research, says Nocera’s 2008 finding of the cobalt-based catalyst was a “major discovery,” and these latest findings “are equally as important, since now the water-splitting reaction is powered entirely by visible light using tightly coupled systems comparable with that used in natural photosynthesis. This is a major achievement, which is one more step toward developing cheap and robust technology to harvest solar energy as chemical fuel.”

Barber cautions that “there will be much work required to optimize the system, particularly in relation to the basic problem of efficiently using protons generated from the water-splitting reaction for hydrogen production.” But, he says, “there is no doubt that their achievement is a major breakthrough which will have a significant impact on the work of others dedicated to constructing light-driven catalytic systems to produce hydrogen and other solar fuels from water. This technology will advance side by side with new initiatives to improve and lower the cost of photovoltaics.”

Nocera’s ongoing research with the artificial leaf is directed toward “driving costs lower and lower,” he says, and looking at ways of improving the system’s efficiency. At present, the leaf can redirect about 2.5 percent of the energy of sunlight into hydrogen production in its wireless form; a variation using wires to connect the catalysts to the solar cell rather than bonding them together has attained 4.7 percent efficiency. (Typical commercial solar cells today have efficiencies of more than 10 percent). One question Nocera and his colleagues will be addressing is which of these configurations will be more efficient and cost-effective in the long run.

Another line of research is to explore the use of photovoltaic (solar cell) materials other than silicon — such as iron oxide, which might be even cheaper to produce. “It’s all about providing options for how you go about this,” Nocera says.

More information: http://www.science … 816.full.pdf

Provided by Massachusetts Institute of Technology (news : web)

1 room -- 63 different dust particles: Researchers aim to build dust library

Researchers recently isolated 63 unique dust particles from their laboratory – and that's just the beginning.

The chemists were testing a new kind of sensor when dust got stuck inside it, and they discovered that they could measure the composition of single dust particles.

In a recent issue of The Journal of Physical Chemistry C, they describe how the discovery could aid the study respiratory diseases caused by airborne particles.

Most dust is natural in origin, explained James Coe, professor of chemistry at Ohio State University. The 63 particles they identified were mainly irregular blobs containing bits of many different ingredients.

The most common ingredient of the dust particles was organic matter, Coe said. "Organic" indicates some kind of plant or animal material, though the researchers can't yet say precisely what kinds of organic matter they found. They are about to do an in-depth analysis to find out.

Quartz was the second-most common ingredient. Both quartz and organic matter were found in more than half of the dust particles the researchers classified. Man-made chemicals from air pollution, fertilizers, and construction materials were also present in small amounts.

"In that way, a single dust particle is like a snapshot of mankind's impact on the environment," Coe said.

 

This is a close up of a single dust particle on the sensor. Credit: Images courtesy of Ohio State University.

Scientists have had some difficulty getting precise measurements of dust composition, in part because standard techniques involve studying dust in bulk quantities rather than individual particles.

Nowhere is dust composition more important than in public health, where some airborne particulates have been linked to diseases. Coe cited silica dust from mining operations, which causes a lung disease called silicosis.

The patented sensor that Coe's team was testing – a type of metal mesh that transmits infrared light through materials caught in the holes – is ideal for picking up minute details in the composition of single dust grains.

"We can separate particles by size to isolate the ones that are small enough to get into people's lungs, and look at them in detail," he added.

Coe didn't set out to study dust. He and his team invented the metal mesh sensor in 2003, and discovered that they could use it to create surface plasmons – mixtures of conducting electrons and photons. The effect boosts the intensity of light passing through microscopic holes in the mesh, and lets scientists record a detailed infrared light spectrum. Any material stuck in the holes will leave a unique signature on the spectrum, so the sensor can be used to identify the chemicals in microscopic samples.

Early this year, the researchers were testing how light flows through the sensor, and they coated the mesh with a ring of tiny latex spheres to take a baseline measurement. The result should have been a spectrum unique to latex, but instead the spectrum carried the signature of several common minerals due to a single dust particle that had gotten inside the sensor – most likely from the laboratory air.

Coe launched a contest among his students to see who would be the first to take an infrared spectrum of a single dust particle – and an electron microscope image of the same particle. The winner got a free lunch and the chance to name the particle for publication.

Matthew McCormack, then an honors undergraduate student in the lab, won the contest and named the dust particle after his dog, Abby. His study of the particle formed the basis for his honors thesis, and the data has since been used by Coe and other members of the team in publications and presentations.

In subsequent tests, the students were able to isolate and study 63 individual dust particles from the air of their laboratory. The spectra they obtained with the sensor were free of scattering effects and stronger than expected.

The result is a library of common dust components from the lab. Forty of the particles (63 percent) contained organic material. The most common mineral was quartz, which was present in 34 (54 percent) of the particles, followed by carbonates (17 particles, or 27 percent), and gypsum (14 particles, or 22 percent).

Currently, Coe and his team are constructing computer algorithms to better analyze the mineral components and reveal details about the organic components.

A library of common dust components would be useful for many areas of science, he said.

Eventually, researchers in public health could use the sensor as a laboratory tool to analyze dust particles. It could also enable studies in astronomy, geology, environmental science, and atmospheric science.

Provided by The Ohio State University (news : web)

Faster, cheaper Mercury test could provide answers for China

Mercury pollution is a big problem, and it’s only getting bigger. It is most pronounced in developing countries like China and India, where coal-burning still remains a major resource of power generation. Worldwide, about 1,000 tons of mercury is produced per year. The resulting pollution makes water and soil unusable, and poses substantial health risks to people nearby.

University of Utah researcher Ling Zang hopes to address this growing problem in China and beyond with a new test for detecting mercury. The test promises to be faster and cheaper than conventional tests, which require samples to be sent to a laboratory, can take weeks to process and can cost hundreds of dollars.

“It’s very exciting as a scientist to be able to transfer what you are developing on the bench-top in the lab to the marketplace, and to serve society,” said Zang, who was recruited to the university’s Department of Material Science and Engineering in 2008 by the Utah Science Technology and Research (USTAR) initiative. USTAR is a state office that drives innovation and economic growth by attracting talented researchers to Utah.

“One of the main reasons I decided to move to University of Utah was the level of support for commercialization at this university,” Zang added. “It is essential to have support from the faculty, the administration and the state to increase the impact of new technologies on people’s lives.”

The inspiration for the new mercury test came four years ago, when Zang was reading an article about how mercury binds to DNA, causing irregularity of genetic processing. He identified the strong, specific binding between mercury and the DNA base thymine, and discovered a way to use this binding to measure mercury concentrations.

After years of work, Zang has proven his new test, and he is close to selling it to companies and governments across the world that want to monitor mercury pollution. The test can detect mercury down to 0.20 parts per billion (ppb), which is well below the Environmental Protection Agency’s standard of 2 ppb for drinking water. The cost of running the analysis has yet to be determined, but it is expected to cost a fraction of exiting tests.

The new test starts with a liquid solution of a perylene dye, which emits a green fluorescent light. Zang attached the mercury-binding group to the perylene, so when mercury is added, the liquid becomes less fluorescent. The less fluorescent the liquid, the more mercury is present. To measure the fluorescence, Zang uses a custom hand-held photodetector, an electronic device that measures light.

Zang is commercializing his test through a startup company called Metallosensors, Inc. The company launched in 2009, and now has the leadership and money needed to refine and market the test. Metallosensors was awarded a $150,000 phase I SBIR (Small Business Innovation Research) grant from the National Science Foundation. Next year, the company will apply for the $500,000 Phase II SBIR. In addition, Metallosensors recently secured a $50,000 VIP (Virtual Incubator Program) grant from the University of Utah.

The CEO of the company is Glenn Prestwich, a veteran entrepreneur – cofounder and chief science officer for five University of Utah startup companies – and Presidential Professor of Medicinal Chemistry at the U.

“Our molecular sensor has enormous potential,” Prestwich said. “In the short term, we are perfecting the underlying chemical test, developing the handheld photodetector with partners in China, establishing a marketing plan in China, and securing intellectual property protection. We are also engaging with Utah’s Mercury Working Group to develop products for monitoring in the United States. In the future, we hope to make the test smarter by adding GPS and real-time graphical displays. This will significantly improve the way we track mercury pollution.”

Metallosensors got an early boost from the Venture Bench program of the University of Utah’s Technology Commercialization Office (TCO). This program helps early stage university startups such as Metallosensors by creating a temporary management team that allows them to apply for an SBIR grant. Venture Bench also provides marketing materials, including a website and logo.

“Metallosensors is a big success for the Venture Bench program,” said Rajiv Kulkarni, Associate Director at the TCO who has helped Metallosensors through the patent and commercialization process. “The technology is very promising, and the company product line addresses a real need to monitor contamination, especially in developing countries. The portability of the instrument will make it very convenient for field use.”

Provided by University of Utah (news : web)

Researchers produce cheap sugars for sustainable biofuel production

Iowa State University's Robert C. Brown keeps a small vial of brown, sweet-smelling liquid on his office table.

"It looks like something you could pour on your pancakes," he said. "In many respects, it is similar to molasses."

Brown, in fact, calls it "pyrolytic molasses."

That's because it was produced by the fast pyrolysis of biomass such as corn stalks or wood chips. Fast pyrolysis involves quickly heating the biomass without oxygen to produce liquid or gas products.

"We think this is a new way to make inexpensive sugars from biomass," said Brown, an Anson Marston Distinguished Professor in Engineering, the Gary and Donna Hoover Chair in Mechanical Engineering and the Iowa Farm Bureau Director of Iowa State's Bioeconomy Institute.

That's a big deal because those sugars can be further processed into biofuels. Brown and other Iowa State researchers believe pyrolysis of lignocelluslosic biomass has the potential to be the cheapest way to produce biofuels or biorenewable chemicals.

Brown and Iowa State researchers will present their ideas and findings during tcbiomass2011, the International Conference on Thermochemical Conversion Science in Chicago Sept. 28-30. On Thursday, Sept, 29, Brown will address the conference with a plenary talk describing how large amounts of sugars can be produced from biomass by a simple pretreatment before pyrolysis. He'll also explain how these sugars can be economically recovered from the products of pyrolysis.

A poster session following Brown's talk will highlight thermochemical technologies developed by 19 Iowa State research teams, including processes that:
increase the yield of sugar from fast pyrolysis of biomass with a pretreatment that neutralizes naturally occurring alkali that otherwise interferes with the release of sugarsprevent burning of sugar released during pyrolysis by rapidly transporting it out of the hot reaction zonerecover sugar from the heavy end of bio-oil that has been separated into various fractionsseparate sugars from the heavy fractions of bio-oil using a simple water-washing process.In addition to Brown, key contributors to the pyrolysis research at Iowa State include Brent Shanks, the Mike and Jean Steffenson Professor of Chemical and Biological Engineering and director of the National Science Foundation Engineering Research Center for Biorenewable Chemicals based at Iowa State; Christopher Williams, professor of civil, construction and environmental engineering; Zhiyou Wen, associate professor of food science and human nutrition; Laura Jarboe, assistant professor of chemical and biological engineering; Xianglan Bai, adjunct assistant professor of aerospace engineering; Marjorie Rover and Sunitha Sadula, research scientists at the Center for Sustainable Environmental Technologies; Dustin Dalluge, a graduate student in mechanical engineering; and Najeeb Kuzhiyil, a former doctoral student who is now working for GE Transportation in Erie, Penn.

Their work has been supported by the eight-year, $22.5 million ConocoPhillips Biofuels Program at Iowa State. The program was launched in April 2007.

Brown said Iowa State will – literally – take a bus load of students and researchers to the Chicago conference to present their work on thermochemical technologies, including production of sugars from biomass.

"The Department of Energy has been working for 35 years to get sugar out of biomass," Brown said. "Most of the focus has been on use of enzymes, which remains extremely expensive. What we've developed is a simpler method based on the heating of biomass."

Provided by Iowa State University (news : web)

New technology enables molecular-level insight into carbon sequestration

 

Flaviu Turcu co-invented a novel NMR system for carbon sequestration research applications with EMSL staff, David Hoyt (Principal Investigator) and Jesse Sears, and PNNL colleagues, Jian Zhi Hu and Kevin Rosso. Turcu, pictured above, holds the high-pressure MAS rotor and stands behind the high-pressure rotor loading reaction chamber pieces of the system.

Carbon sequestration is a potential solution for reducing greenhouse gases that contribute to climate change, but its scientific challenges are complex. Analytical tools are needed that provide information about the mineral-fluid interactions of carbon dioxide (CO2) at the molecular level.

As part of Pacific Northwest National Laboratory (PNNL)'s Carbon Sequestration Initiative, a team of EMSL and PNNL researchers developed and patented such a tool—a unique high-pressure magic angle spinning (MAS) nuclear magnetic resonance (NMR) capability that operates in conditions characteristic of geologic carbon sequestration.

Described in the September 2011 issue of the Journal of Magnetic Resonance, this new technology consists of a reusable high-pressure MAS rotor, a high-pressure rotor loading/reaction chamber for in situ sealing and reopening of the high-pressure MAS rotor, and a MAS probe with a localized radiofrequency coil for background signal suppression.

This new capability can help determine reaction intermediates and final products that occur during mineral dissolution reactions relevant to the geologic disposal of CO2, as these researchers reported in the July 2011 issue of the International Journal of Greenhouse Gas Control.

Identifying reaction intermediates is not possible using only ex situ measurements and is critical to determining the mechanisms of mineral dissolution at high pressures. This new capability has the potential to further the exploration of solid-state chemistry at new levels of high pressure and temperature in many science areas.

More information: References: Hoyt DW, RVF Turcu, JA Sears, KM Rosso, SD Burton, AR Felmy, and JZ Hu. 2011. “High-pressure Magic Angle Spinning Nuclear Magnetic Resonance,” Journal of Magnetic Resonance, DOI:10.1016/j.jmr.2011.07.019

Hoyt DW, JA Sears, RVF Turcu, KM Rosso, and JZ Hu. 2011. U.S. Patent submission E-16894, “Devices and Process for High-Pressure Magic Angle Spinning Nuclear Magnetic Resonance,” filed July 28, 2011 (provisional patent submitted December 13, 2010).

Kwak JH, JZ Hu, RVF Turcu, KM Rosso, ES Ilton, C Wang, JA Sears, MH Engelhard, AR Felmy, and DW Hoyt. 2011. "The Role of H2O in the Carbonation of Forsterite in Supercritical CO2." International Journal of Greenhouse Gas Control 5:1081-1092.

Provided by Environmental Molecular Sciences Laboratory (news : web)

Understanding lethal synthesis

The chemical reaction which makes some poisonous plants so deadly has been described by researchers at the University of Bristol in a paper published today in Angewandte Chemie.

Professor Adrian Mulholland in the School of Chemistry and colleagues successfully analyzed why a particular toxic product originating from sodium fluoroacetate (a colourless salt used as a rat poison) is formed in an enzyme.

Professor Mulholland said: “The reaction could go in one of two ways, and only one of those two makes a poison.  The difference is very subtle, just in terms of which one of two hydrogen atoms is removed by the enzyme in the reaction.

 “This process gives rise to 'lethal synthesis', that is where something non-toxic is converted into a poison in the body.  It is responsible for the lethal toxicity of fluoroacetate to humans and other mammals and explains, for example, why plants such as gifblaar in South Africa and Gastrolobium bilobum (heart-leaved poison) in Australia kill sheep and cattle, and why ‘1080’ is such a potent rat poison.”

The Bristol team used high-level quantum mechanics/molecular mechanics (QM/MM) modelling to successfully explain how the enzyme citrate synthase (CS) converts fluoroacetyl-CoA from fluoroacetate to fluoricitrate, which is what makes fluoroacetate toxic.  Only the particular form of fluorocitrate made by the enzyme is poisonous; if it made the mirror image molecule instead, the result would not be a poison.  The Bristol team’s calculations show why the enzyme produces this form.

CS performs the first reaction in the citric acid cycle, a series of enzyme-catalysed chemical reactions which is of central importance in all living cells.  In this reaction, citrate, a six-carbon compound, is formed from a two-carbon acetate in the form of acetyl-CoA and the four-carbon acceptor compound oxaloacetate.

However, if fluoroacetyl-CoA from fluoroacetate is present instead of acetyl-CoA, fluorocitrate is formed.  The particular form (isomer) of fluorocitrate, and only this isomer, goes on to react with and inhibit (block) aconitase, the next enzyme in the citric acid cycle.  This causes citrate to build-up in tissue and blood, turning off most of the energy supply to cells and resulting in tissue damage and death.

By explaining the conversion of fluoroacetyl-CoA to fluorocitrate by CS, the Bristol research has shed light on an archetypal enzyme selectivity problem.  Greater understanding of such problems could assist the prediction of selectivity in enzyme-catalyzed reactions which has potential practical applications in catalyst design and drug metabolism.

The research is published today in Angewandte Chemie, the journal of the German Chemical Society.  The study has been classed as a Very Important Paper (VIP) according to the evaluation of three referees.

More information: “Lethal Synthesis” of Fluorocitrate by Citrate Synthase Explained through QM/MM Modeling’ by Marc W. van der Kamp, John D. McGeagh, and Adrian J. Mulholland in Angewandte Chemie. http://onlinelibra … 0.1002/(ISSN)1521-3773/

Provided by University of Bristol (news : web)

NASA scientist unveils new chemical detection technology

 NASA scientists are creating technology that can detect hazardous chemical compounds in the air with a smart phone.

Jing Li, a physical scientist at NASA's Ames Research Center, Moffett Field, Calif., demonstrated this innovative technology called Cell-All in a training exercise on Sept. 28, 2011, at the Los Angeles Fire Department, Los Angeles.

The technology was used to detect carbon monoxide in a response and rescue training exercise for Los Angeles fire and police departments. The U.S. Department of Homeland Security's Science and Technology (S&T) Directorate, in partnership with the Los Angeles Fire Department, Los Angeles Police Department and the California Environmental Protection Agency, sponsored the training exercise.

"This new technology can enhance both personal and public safety by utilizing a common device, such as a cell phone, to detect hazardous chemicals," said Stephen Dennis, technical director of S&T’s Homeland Security Advanced Research Projects Agency. "Our goal is to create a lightweight, cost-effective, power-efficient resource for widespread public use."

The Cell-All technology, consisting of an energy-efficient sensor and cell phone application, detects toxic chemicals and alerts individuals and public safety authorities. Users have the option of using the sensor in a personal mode, which provides personal alerts, or opting-in to a network service, providing anonymous reports of the environmental condition to local responder networks.

Two different prototypes of Cell-All were demonstrated: one developed by NASA’s Center for Nanotechnology at Ames and a prototype developed in partnership between Qualcomm Inc., San Diego, Calif. and Synkera Technologies Inc., Longmont, Colo.

To see images of the cell phone sensors, visit: http://www.nasa.go … sensors.html

Provided by JPL/NASA (news : web)

Imaging inflammation in the living brain

Inflammation occurs in the human brain during illnesses such as Alzheimer's disease, Parkinson’s disease, stroke and traumatic brain injury. Now, a research team in Japan has developed a probe that can bind to the pro-inflammatory enzyme cyclooxygenase (COX). The probe, 11C-ketoprofen methyl ester, enables researchers to observe when and where the enzyme is acting in the brains of living animals using positron emission tomography (PET) imaging.

In PET imaging, a radioactive tracer that binds specifically to a specific molecule in the body is injected into a living organism. Images are then taken with a PET scanner, indicating where in the body that tracer is found.

Led by Hirotaka Onoe at the RIKEN Center for Molecular Imaging Science in Kobe, the researchers had previously discovered that 11C-ketoprofen methyl ester could recognize COX, but not which of its two forms. To determine which isoform is responsible for binding their molecular probe, Miho Shukuri, a young member of Onoe’s team, utilized a series of mice lacking the genes for either COX-1 or COX-2. She found that the PET probe could bind to the brains of COX-2-deficient mice, but not to those lacking COX-1. According to the researchers, 11C-ketoprofen methyl ester is therefore the first PET probe that is specific to COX-1 in living animals.

When Shukuri injected bacterial antigens into the brain of rats to induce inflammation, she saw the PET probe build up in the brain within six hours to one day after antigen injection. The levels dropped a week later. Because COX-1 is rapidly activated by brain injury, this may mean that administration of drugs that block COX-1 soon after injury could prevent the progression of brain damage. “COX-1 could therefore be a promising target for the neurodegenerative diseases that exhibit neuro-inflammation,” explains Onoe.

Microglia are immune cells in the brain that proliferate in response to injury, while macrophages are immune cells normally found within the blood that invade the brain after injury. The researchers observed that the injury-induced increase in brain COX-1 seemed to occur within microglia and macrophages (Fig. 1), which also became more numerous in the brain after exposure to bacterial antigens. Other research groups have found COX-1-expressing microglia in diseases such as Alzheimer's disease, Parkinson’s disease and multiple sclerosis. This suggests to Onoe and colleagues that 11C-ketoprofen methyl ester could be used to track the time course and localization of increased COX-1 expression in living organisms, including humans, suffering from diseases linked to neuro-inflammation.

More information: Shukuri, M., et al. In vivo expression of cyclooxygenase-1 in activated microglia and macrophages during neuroinflammation visualized by PET with 11C-ketoprofen methyl ester. The Journal of Nuclear Medicine published online 1 July, 2011 (doi: 10.2967/jnumed.110.084046).

Takashima-Hirano, M., et al. General method for the 11C-labeling of 2-arylpropionic acids and their esters: construction of a PET tracer library for a study of biological events involved in COXs expression. Chemistry 16, 4250–4258 (2010).

Provided by RIKEN (news : web)

Laser pioneer or electrochemist for Nobel?

(AP) -- Americans William Moerner, Allen Bard and Richard Zare could be among the potential candidates when the Nobel Prize in chemistry is announced Wednesday.

Guessing a winner among scores of discoveries in such a broad field as chemistry is notoriously hard but that doesn't stop people from trying.

Recent discoveries are more or less ruled out because Nobel jurors look for research that has stood the test of time. Typically, Nobel winners have received plenty of other awards before they get the call from Stockholm.

Both Zare, a laser chemistry pioneer at Stanford University, and Bard, an electrochemistry expert of the University of Austin, Texas, have been decorated with multiple honors, including the Priestley Award, handed out by the American Chemical Society, and Israel's Wolf Prize.

Bard shared the latter in 2008 with Moerner, of Stanford University, for creating a new field of science: single-molecule spectroscopy and imaging.

Should the chemistry prize committee chose a woman, for a change, American Jacqueline Barton, of the California Institute of Technology, could get the nod for her work on the transport of electrons in DNA.

Only four women have won the chemistry prize since the awards were first handed out in 1901: French scientist Marie Curie (1911), her daughter Irene Joliot-Curie (1935), British chemist Dorothy Crowfoot Hodgkin (1964) and Ada Yonath of Israel (2009).

Other names that routinely pop up in Nobel speculation include Americans Stuart Schreiber and Gerald Crabtree for work that sheds light on how tiny molecules can be used on cell circuits and signaling pathways.

If the prize honors nanotechnology - the science dedicated to building materials from the molecular level - possible winners could include American Charles Lieber, British chemist James Fraser Stoddart or Japan's Sumio Iijima, who discovered carbon nanotubes in 1991.

The Nobel Prize in chemistry announcement will cap this year's science awards.

Immune system researchers Bruce Beutler of the U.S. and Frenchman Jules Hoffmann shared the medicine prize Monday with Canadian-born Ralph Steinman, who died three days before the announcement. U.S.-born scientists Saul Perlmutter, Brian Schmidt and Adam Riess won the physics prize on Tuesday for discovering that the universe is expanding at an accelerating pace.

Last year, the chemistry committee rewarded Japanese scientists Ei-ichi Negishi and Akira Suzuki and American Richard Heck for designing a technique to bind together carbon atoms, a key step in assembling the skeletons of organic compounds used in medicine, agriculture and electronics.

The 10 million kronor (US$1.4 million) Nobel Prizes are handed out every year on Dec. 10, the anniversary of award founder Alfred Nobel's death in 1896.

?2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Advance offers new opportunities in chemistry education, research

Researchers at Oregon State University have created a new, unifying method to describe a basic chemical concept called "electronegativity," first described almost 80 years ago by OSU alumnus Linus Pauling and part of the work that led to his receiving the Nobel Prize.

The new system offers simplicity of understanding that should rewrite high school and college chemistry textbooks around the world, even as it opens important new avenues in materials and chemical research, with possible applications in everything from solar energy to solid state batteries.

The findings were just published in the Journal of the American Chemical Society, in work supported by the National Science Foundation and the U.S. Department of Energy.

"This is a quantum leap forward in understanding basic tendencies in chemical bond formation," said John Wager, a professor of electrical engineering at OSU. "We can now take a concept that college students struggle with and I could explain it to a kindergarten class.

"Even advanced scientists will gain new insights and understanding into the chemical processes they study," Wager said. "Using this system, I could look at various materials being considered for use in new solar energy cells and determine quickly that this one might work, that one doesn't stand a chance."

Electronegativity, as defined by Pauling, is "the power of an atom in a molecule to attract electrons to itself." This concept is useful for explaining why some atoms tend to attract electrons, others share them and some give them away. In the 1930s, Pauling was the first to devise a method for numerically estimating the electronegativity of an atom. Other researchers later developed different approaches.

The new system developed at OSU – the first of its type since the early 1990s - is called an atomic "solid state energy scale." It characterizes electronegativity as the solid state energy of elements in a compound, and shows that electrons simply move from a higher energy to a lower energy.

"This is a remarkably intuitive approach to understanding electronegativity, and yet it's based on data that are absolute, not arbitrary," said Douglas Keszler, an OSU professor of chemistry, co-author on the study and an international expert in materials science research.

"This is already one of the best instruments in my tool box for predicting the properties of new materials and understanding inorganic reactions," Keszler said. "It's not only more accurate and comprehensive, it just offers a simplicity of understanding that is very important."

The electronegativity scale developed by Pauling is among the most widely known of his contributions in studies on the nature of the chemical bond, the work for which he received a Nobel Prize in chemistry.

According to Ram Ravichandran, an electrical engineering student at OSU and co-author of the study, the new approach is based on the study of how the "band gap," a fundamental property of materials, varies for a variety of compounds. This helps to derive an absolute energy reference and a new solid state energy scale, providing a surprisingly simple way to visualize the way materials will interact.

The system could aid research in new semiconductor devices, catalysts, solar cells, light emitting materials and many other uses.

Provided by Oregon State University (news : web)