Chemistry News Archive April 2009

Cousin of the "ice that burns" emerges as greener new way to fight fires

Researchers in Japan are reporting development of a new type of ice that may provide a more efficient, environmentally-friendly method for putting out fires, including out-of control blazes that destroy homes and forests. Their study appears in the current issue of ACS' Industrial & Engineering Chemistry Research, a bi-weekly journal.

Toshihisa Ueda and colleagues note in the new study that firefighters have used water and carbon dioxide as fire extinguishing agents for decades. That knowledge led the scientists on a quest to see if carbon dioxide hydrates, frozen crystals made of water and carbon dioxide bonded together, may serve as promising fire-suppressing materials. Such icy chunks occur naturally in some parts of the world, including hydrates containing methane. Methane hydrates are a potential new source of natural gas, and are renowned as the "ice that burns." They burst into flame when ignited.

To test their idea, the scientists used a special reactor to produce tiny pellets of carbon dioxide hydrates in the laboratory. They compared the fire-suppressing performance of these hydrates to similar-sized pellets made of normal ice (frozen water) and dry ice (frozen carbon dioxide) after sprinkling them onto several small, carefully controlled fires. The hydrates extinguished flames faster than the other two substances, they say. The hydrates also used less water than ordinary ice and released less carbon dioxide than dry ice, they note. Grinding the pellets into smaller pieces boosted their flame-fighting efficiency, the researchers say. - MTS

Industrial & Engineering Chemistry Research: "Fire Extinction Using Carbon Dioxide Hydrate" [Ind. Eng. Chem. Res., 2009, 48 (8), pp 4083?4087; DOI: 10.1021/ie8019533].

New biosensor for most serious form of Listeria food poisoning bacteria

Scientists in Indiana are reporting development of a new biosensor for use in a faster, more sensitive test for detecting the deadliest strain of Listeria food poisoning bacteria. That microbe causes hundreds of deaths and thousands of hospitalizations each year in the United States, particularly among people with weakened immune systems. Their study appears in the current issue of ACS' Analytical Chemistry, a semi-monthly journal.

Arun Bhunia and colleagues note in the new study that fast, highly effective tests already are available for five of the six known species of Listeria. These tests use antibodies that signal the presence of the bacteria. However, no rapid, sensitive tests are available for detecting Listeria monocytogenes, the deadliest of the species, the researchers say.

The scientists describe development of the biosensor using so-called heat shock proteins - which the body produces in response to stress - instead of the antibodies used in other tests. They showed that their new sensor was faster and more sensitive at detecting the deadly bacterium than antibody-based tests. It had a microbe capture rate up to 83 percent higher than antibody-based tests. The new biosensor will reduce the likelihood of false-positive results for Listeria monocytogenes and may lead to improved tests for detecting other types of dangerous pathogens, the researchers say. - MTS

Analytical Chemistry: "Targeted Capture of Pathogenic Bacteria Using a Mammalian Cell Receptor Coupled with Dielectrophoresis on a Biochip" [Anal. Chem., 2009, 81 (8), pp 3094?3101; DOI: 10.1021/ac9000833]

"Self-healing" polymer may facilitate recycling of hard-to-dispose plastic

Researchers in The Netherlands are reporting development of a new plastic with potential for use in the first easy-to-recycle computer circuit boards, electrical insulation, and other electronics products that now wind up on society's growing heaps of electronic waste. Their study appears in ACS' Macromolecules, a bi-weekly journal.

Antonius Broekhuis and colleagues note in the new study that so-called thermoset plastics are widely used in consumer electronics due to their hardness and heat resistance. These plastics, however, contain additives and reinforcement materials that make them almost impossible to recycle. So-called thermoplastics, in contrast, are softer and can be remelted easily. As a result, thermoset plastics often end up in landfills or incinerators, where they can contribute to pollution. Scientists have long-sought a simple, inexpensive process to make these plastics recyclable, but they have been largely unsuccessful until now.

Broekhuis and colleagues describe development of a new type of thermosetting plastic that can be melted and remolded without losing its original heat-resistance and strength. The scientists showed in laboratory tests that they could melt granules of what they term a "self-healing" polymer and reform them into uniform, rigid plastic bars. They also showed that the plastic could be remolded multiple times, setting the stage for a new generation of recyclable plastics. - MTS

Macromolecules: "Thermally Self-Healing Polymeric Materials: The Next Step to Recycling Thermoset Polymers?" [Macromolecules, 2009, 42 (6), pp 1906?1912; DOI: 10.1021/ma8027672].

Presto! Fast color-changing material may lead to improved sunglasses

Researchers in Japan are reporting development of a new so-called "photochromic" material that changes color thousands of times faster than conventional materials when exposed to light. The development could lead to a wide range of new products including improved sunglasses, more powerful computers, dynamic holograms, and better medicines, the researchers say. Their report appears in the Journal of the American Chemical Society, a weekly publication.

In the new study, Jiro Abe and colleagues note that photochromic materials are most familiar as the invisible layers found in the lenses of many high-end sunglasses, which change color when exposed to sunlight. For years, researchers have explored the possibility of using these unusual materials for optical data storage in computers and as "molecular switches" for more controlled drug delivery. Conventional photochromic materials, however, tend to be relatively slow-acting (tens of seconds to hours) and unstable, which prevents their use for many advanced applications, the scientists say.

The scientists describe development of a unique photochromic material that shows instantaneous coloration upon exposure to ultraviolet light and its disappearance within tens of milliseconds when the light is turned off. The decoloration speed is thousands of times faster than conventional materials. The material is also more stable and longer-lasting, they note. In laboratory studies, the scientists showed that the new material could instantly change from colorless to blue in both solid form and in solution when they exposed the molecules to ultraviolet light, and quickly back to colorless when the light is turned off. The development opens the door to futuristic technologies "with unprecedented switching speeds and remarkable stabilities," the article notes. - MTS

Journal of the American Chemical Society:
"A Fast Photochromic Molecule That Colors Only under UV Light",
[J. Am. Chem. Soc., 2009, 131 (12), pp 4227?4229; DOI: 10.1021/ja810032t];
Photochromic Material Video

Potholes on the road to ethanol from crop waste rather than food crops

Those highly publicized efforts to produce ethanol fuel from wheat straw, corn cobs, and other crop waste - rather than food crops - appear to be stalling as biofuel companies face mounting difficulties bringing it to the marketplace. That's according to an article scheduled for the April 27 issue of Chemical & Engineering News, ACS' weekly newsmagazine.

C&EN senior business editor Melody Voith explains in the magazine's cover story that the U.S. Department of Energy (DOE) in 2007 selected six "cellulosic ethanol" projects for up to $385 million in grants. The project's goal was to reduce America's reliance on foreign oil and make ethanol cost-competitive with gasoline by 2012. But construction has started on only one of the projects, with two cancelled outright, the article notes.

The biggest roadblock involves difficulty in scaling-up production from the small quantities of bioethanol that can be produced in the lab to the millions of gallons needed for commercial use. Other hurdles: Obtaining sufficient raw materials for commercial-scale production, financing construction costs in the hundreds of millions of dollars, and securing stable markets for bioethanol. Nevertheless, DOE managers express confidence that the emerging bioethanol industry can surmount these problems.

Chemical & Engineering News: "Cellulosic Scale-Up".

First broad spectrum anti-microbial paint to kill 'superbugs'

Scientists in South Dakota are reporting development of the first broad-spectrum antimicrobial paint, a material that can simultaneously kill not just disease-causing bacteria but mold, fungi, and viruses. Designed to both decorate and disinfect homes, businesses, and health-care settings, the paint is the most powerful to date, according to their new study. It appears in the current issue of the monthly ACS' Applied Materials & Interfaces. The paint shows special promise for fighting so-called "superbugs," antibiotic-resistant microbes that infect hospital surfaces and cause an estimated 88,000 deaths annually in the United States, the researchers say.

In the study, Yuyu Sun and Zhengbing Cao note in the antimicrobial paints already on are store shelves. These paints, however, are only effective against a narrow range of disease-causing microorganisms, limiting their usefulness.

The scientists already were aware of research on the germ-killing effects of that N-halamines, bleach-like substances already in wide use. They developed a new antimicrobial polymer that includes a type of N-halamine. It has no undesirable effects on the quality of latex paints. Laboratory tests showed that the new polymer kills a wide range of disease-causing microbes including those resistant to multiple antibiotics. The paint retains an anti-microbial punch for extended periods, and it can be easily "recharged" with a simple chlorination process, the researchers note. - MTS

ACS Applied Materials & Interfaces: "Polymeric N-Halamine Latex Emulsions for Use in Antimicrobial Paints" [ACS Appl. Mater. Interfaces, 2009, 1 (2), pp 494?504; DOI: 10.1021/am800157a].

Atmospheric engineering scheme to combat global warming could diminish solar power

A widely discussed "atmospheric engineering" scheme intended to combat global warming could have unanticipated consequences in reducing the effectiveness of certain kinds of solar power around the Earth, a new study has concluded. It is appears in the current issue of ACS' Environmental Science & Technology, a semi-monthly journal.

In the study, the National Oceanographic and Atmospheric Administration's Daniel M. Murphy examines a proposal to minimize climate change by enhancing the stratospheric aerosol layer, which reduces sunlight to Earth by scattering it to outer space. But this approach has considerable implications on the ability to concentrate solar power, Murphy says. For example, the increased aerosols resulting from the 1991 eruption of Mt. Pinatubo in the Philippines reduced global sunlight by less than three percent but decreased output from some solar generating plants by about 20 percent.

Murphy's study found that aerosols reduce direct sunlight - the kind that casts shadows - much more than total sunlight. Each one percent reduction in the Earth's sunlight due to aerosols will cause a four to 10 percent loss in output from concentrating solar power applications. He notes, however, that flat solar hot water and photovoltaic panels - which utilize both direct and diffuse (scattered) sunlight - will have smaller performance losses than concentrating solar collectors.

"One consequence of deliberate enhancement of the stratospheric aerosol layer would be a significant reduction in the efficiency of solar power generation systems," Murphy concludes. "Any cooling of the Earth that relies on light scattering, including tropospheric aerosol scattering and increased cloudiness, by particles will also result in reductions in direct sunlight that are several times the reductions in total sunlight." - JS

Environmental Science & Technology: "Effect of Stratospheric Aerosols on Direct Sunlight and Implications for Concentrating Solar Power" [Environ. Sci. Technol., 2009, 43 (8), pp 2784?2786; DOI: 10.1021/es802206b].

India's "holy powder" finally reveals its centuries-old secret

Scientists in Michigan are reporting discovery of the secret behind the fabled healing power of the main ingredient in turmeric - a spice revered in India as "holy powder." Their study on the ingredient, curcumin, appears in the Journal of the American Chemical Society, a weekly publication.

In the study, Ayyalusamy Ramamoorthy and colleagues point out that turmeric has been used for centuries in folk medicine to treat wounds, infections, and other health problems. Although modern scientific research on the spice has burgeoned in recent years, scientists until now did not know exactly how curcumin works inside the body.

Using a high-tech instrument termed solid-state NMR spectroscopy, the scientists discovered that molecules of curcumin act like a biochemical disciplinarian. They insert themselves into cell membranes and make the membranes more stable and orderly in a way that increases cells' resistance to infection by disease-causing microbes. - AD

Journal of the American Chemical Society: "Determining the Effects of Lipophillic Drugs on Membrane Structure by Solid-State NMR Spectroscopy ? the Case of the Antioxidant Curcumin" [J. Am. Chem. Soc., 2009, 131 (12), pp 4490?4498; DOI: 10.1021/ja809217u].

Oh rats! New wireless sensor first for instant monitoring of brain oxygen

Scientists in Italy and Ireland are reporting development of the first wireless sensor that gives second-by-second readings of oxygen levels in the brain. The new microsensor - smaller than a dime - could become the basis for tiny devices to help test drugs and other treatments for patients with traumatic brain injury, Alzheimer's and Parkinson's diseases, and other conditions. The study appears in ACS' Analytical Chemistry, a semi-monthly journal.

In the new report, Pier Andrea Serra and colleagues note that the most common method for monitoring brain neurochemical levels is microdialysis, a technique that requires insertion of a relatively big probe into the brain. That technique, however, has several disadvantages including low sample rate and the necessity of a complex analytical apparatus.

Serra and colleagues describe development and testing in laboratory rats of a wireless sensor that overcomes some of those drawbacks. The scientists used a variety of techniques - including physiological stimuli and pharmacological treatments - to raise or lower their brain oxygen levels. The simple sensor quickly and reliably recorded real-time changes in these oxygen levels and can help provide a better understanding of the brain in health and disease, the researchers say. The proposed system could be used in conjunction with a wide range of microsensors and biosensors for monitoring small molecules in the brain. - MTS

Analytical Chemistry: "Real-Time Monitoring of Brain Tissue Oxygen Using a Miniaturized Biotelemetric Device Implanted in Freely Moving Rats" [Anal. Chem., 2009, 81 (6), pp 2235?2241; DOI: 10.1021/ac802390f].

"Neglected" diseases neglected no more

A non-profit offshoot of famed Nobel Prize winning M?ecins sans Fronti?es is joining hands with pharmaceutical companies, government agencies and private donors in a new assault on neglected diseases. Those hard-to-treat diseases include leishmaniasis, sleeping sickness, and Chagas disease. These conditions infect millions of people worldwide each year, killing thousands. An article on this development is scheduled for the April 20 issue of Chemical & Engineering News, ACS' weekly newsmagazine.

C&EN senior editor Rick Mullin explains that just a decade ago major pharmaceutical companies devoted little attention to developing treatments for these diseases - thus the term, "neglected" diseases. That situation, however, has changed, with a nonprofit organization called Drugs for Neglected Diseases Initiative (DNDi) leading the way. DNDi hopes to have at least 6 new drugs for neglected diseases by 2014.

DNDi already has raised $150 million from public and private donors and seeks an additional $200 million by 2014. That cash, combined with a new commitment among pharmaceutical companies, brightens hopes for improving health and saving lives in the developing world, the article suggests.

Chemical & Engineering News: "Paying attention to neglected diseases".

Solving the mystery of what puts sperm "in the mood"

In a potential advance toward a male contraceptive pill and new treatments for infertility, researchers are reporting the identification of key biochemical changes that put sperm "in the mood" for fertilization. Their study, which addresses a long-standing biological mystery, appears in ACS' Journal of Proteome Research, a monthly publication.

Mark Platt and colleagues note in the new study that sperm cannot fertilize an egg immediately after entering the female reproductive tract. Sperm must acquire this ability after undergoing an activation process called "capacitation." Scientists have known for years that this process involves phosphorylation. That common biological modification causes cellular activities to be turned "on" by the addition of phosphate molecules to certain amino acids within proteins. However, the specific biochemical details have been a deep mystery.

Using laboratory mice, the researchers compared the extent of phosphorylation in both capacitated and noncapacitated sperm samples. They identified 44 peptides exhibiting differential phosphorylation, on 59 specific amino acids, suggesting that modification of these particular sites is essential for the capacitation process. The relative ratio of phosphorylation between the capacitated and noncapacitated samples were also reported, providing the first biochemical description of what puts sperm "in the mood." - MTS

Journal of Proteome Research: "Use of Differential Isotopic Labeling and Mass Spectrometry To Analyze Capacitation-Associated Changes in the Phosphorylation Status of Mouse Sperm Proteins" [DOI: 10.1021/pr800796j].

Long-awaited new tests for detecting the bioterrorism agent ricin

In a development that could help safeguard people against potential acts of terrorism involving ricin, two groups of scientists in Georgia and New York are reporting the development of faster, more sensitive tests for detecting the deadly poison. One can detect one billionth of a gram of toxin in a single droplet of fluid in just five minutes, the scientists say. Reports on the tests - the most sensitive to date for detecting ricin - appear in ACS' Analytical Chemistry, a semi-monthly journal.

The scientists note in the new studies that ricin, a ribosomal inactivating protein found in castor beans, is one of the agents most likely to be used in acts of aerosol or food-related bioterrorism. Ricin can be obtained easily and quickly causes death when inhaled or eaten in small amounts. There is no known antidote. Quantitation of ricin also has medical applications, since ricin immunoconjugates have been used as anticancer agents. Although earlier researchers have developed tests capable of identifying ricin by protein recognition methods, existing tests are generally slow, cumbersome, and inaccurate.

In one study, Vern Schramm and Matthew Sturm describe a new test that detects the presence of active ricin in any sample by measuring the release of adenine from specific ricin substrates. Ricin-catalyzed adenine release from ribosomes stops protein synthesis and is the mechanism of action of this deadly toxin. By coupling adenine release to light formation by firefly luciferase, scientists can visualize the presence of ricin by the simple detection of light. The test can detect nanogram (one-billionth of a gram) amounts of ricin in minutes, they note.

In the other, John Barr and Suzanne Kalb describe development of a highly selective three-part test that involves capturing the ricin protein using special antibodies, evaluating the enzymatic activity of the ricin protein by mass spectrometry, and identifying the ricin protein by its amino acid sequence through mass spectrometry. In laboratory tests using small amounts of ricin spiked into food and body fluids, including milk, apple juice, serum, and saliva, the scientists found that the test was highly specific and accurate in comparison to current tests. - MTS

Analytical Chemistry: "Detecting Ricin: A Sensitive Luminescent Assay for Ricin A-chain Ribosome Depurination Kinetics" [DOI: 10.1021/ac8026433].

Bioethanol's impact on water supply 3x higher than once thought

At a time when water supplies are scarce in many areas of the United States, scientists in Minnesota are reporting that production of bioethanol - often regarded as the clean-burning energy source of the future - may consume up to three times more water than previously thought. Their study is scheduled for the April 15 issue of ACS' Environmental Science & Technology, a semi-monthly publication.

Sangwon Suh and colleagues point out in the new study that annual bioethanol production in the U.S. is currently about 9 billion gallons and note that experts expect it to increase in the near future. The growing demand for bioethanol, particularly corn-based ethanol, has sparked significant concerns among researchers about its impact on water availability. Previous studies estimated that a gallon of corn-based bioethanol requires the use of 263 to 784 gallons of water from the farm to the fuel pump. But these estimates failed to account for widely varied regional irrigation practices, the scientists say.

The scientists made a new estimate of bioethanol's impact on the water supply using detailed irrigation data from 41 states. They found that bioethanol's water requirements can be as high as 861 billion gallons of water from the corn field to the fuel pump in 2007. And a gallon of ethanol may require up to over 2,100 gallons of water from farm to fuel pump, depending on the regional irrigation practice in growing corn. However, a dozen states in the Corn Belt consume less than 100 gallons of water per gallon of ethanol, making them better suited for ethanol production. "The results highlight the need to take regional specifics into account when implementing biofuel mandates," the article notes. - MTS

Environmental Science & Technology: "Water Embodied in Bioethanol in the United States" [DOI: 10.1021/es8031067].

It's the metal in the mussel that gives mussels their muscle power

Researchers in California are reporting for the first time that metals are key ingredients that give the coatings of anchoring byssal threads of marine mussels their amazing durability. The study could lead to the design of next-generation coatings for medical and industrial applications, including surgical coatings that protect underlying tissues from abrasion and also life-threatening bacterial infections, the researchers say. Their study appears in ACS' Langmuir, a bi-weekly journal.

In the new study, Herbert Waite and colleagues point out that many existing coatings are severely limited by the materials they cover. A rubber band dipped in molten wax is a good case in point. Once hardened at room temperature, the wax is several times harder and stiffer than the underlying rubber, but even moderate extension shatters the wax. Scientists have been trying for years to develop robust coatings for soft or delicate underlying materials. Until recently, however, scientists knew little about the chemical mechanisms that allow mussels to coat the tendon-like fibers in byssal threads with a material that is both hard and extensible.

The researchers conducted a detailed chemical analysis of the protective outer coating of the byssus in a common species of marine mussel. They found that removing iron and calcium from the coating resulted in a 50 percent decrease in hardness, demonstrating that these metals play a key role in maintaining its integrity. Further insights could lead to the development of futuristic coatings with optimal strength and flexibility for medical and industrial applications, they note. - MTS

Langmuir: "Metals and the Integrity of a Biological Coating: The Cuticle of Mussel Byssus" [DOI: 10.1021/la8027012].

Developing safer, more effective drugs to fight obesity

Safer and more effective drugs to fight obesity appear to be around the corner, but researchers still await a complete understanding of the biological underpinnings of the complex disease, according to an article scheduled for the April 13 issue of Chemical & Engineering News (C&EN), ACS' weekly newsmagazine. Obesity is a growing epidemic that affects more than 72 million people in the United States alone, according to the Centers for Disease Control and Prevention.

C&EN assistant editor Carmen Drahl notes in the magazine's two-part cover story that, despite billions of dollars spent on obesity research, researchers still do not fully understand the mechanisms of the disease. This lack of understanding is behind the recent setbacks among several once-promising anti-obesity drugs, according to the article. These problems include a wide range of side effects such as heart valve defects, high blood pressure, and psychiatric symptoms such as depression and anxiety, the article notes.

But researchers have recently made inroads into why some of those setbacks occurred in the first place. These insights have led to the development of promising new drugs that are more targeted for key appetite-control receptors in the brain and elsewhere in the body, according to the article. As a result, these drugs pose a lower likelihood of side effects while promoting weight loss. However, the reasons behind some obesity drugs' psychiatric side effects are not as clear cut, and researchers are still eager to learn more about how the brain controls food intake and how it communicates with the gut. "Obesity is so complex and so multi-factorial that it's hard to find a silver bullet," says one scientist involved in obesity drug development. "I think we're just scratching the surface."

Chemical & Engineering News: "Weighing options: Obesity researchers assess what it will take to move forward in the wake of drug-trial setbacks".