ACS Chemistry for Life

Making solar panels with cleaner, greener technology
Chemical & Engineering News

Current silicon-based solar panels, which represent about 80 percent of the global market, are energy-intensive to manufacture and rely on materials that pose potential health and environmental risks. C&EN Associate Editor Sarah Everts describes the beginning of a scientific effort to manufacture solar panels in a way that better fits the public perception. To be “green,” manufacturers must adopt more environmentally friendly manufacturing processes and plan for the safe end-of-service-life disposal of the panels. Some solar panel manufacturers are setting up programs that will collect and recycle panels after their 20-25 year lifespan. Many solar companies are trying to reduce the amount of energy required to produce the panels, while others are trying to change the production process in order to replace toxic materials with more eco-friendly ones. At the same time, manufacturers are faced with the challenge of developing more efficient solar cells, which could require the use of more energy-intensive processes and more materials. “Resolving these challenges – perhaps with new manufacturing processes altogether – will ensure that photovoltaics [solar panels] don’t just produce renewable energy but are themselves renewably produced,” the article states.

Discovery of the secrets that enable plants near Chernobyl to shrug off radiation
Environmental Science & Technology

Martin Hajduch and colleagues note that plants had an unexpected ability to adapt to an environment contaminated with radiation following the April 26, 1986 accident at the Chernobyl Nuclear Power Plant. Their previous research, for example, showed that soybean plants in the area have adapted to the contaminated soil with certain changes in their proteome. A proteome is the full complement of proteins produced by the genes in a plant or animal. The scientists grew flax seeds in radiation-contaminated soil in the Chernobyl region and compared their growth to those of seeds grown in non-radioactive soil. Radiation exposure had relatively little effect on the protein levels in the plants, with only about five percent of the proteins altered, they note. Among them were certain proteins involved in cell signaling, or chemical communication, which might help the plants shrug off radioactivity, the scientists suggest.

“Toxic toy crisis” requires fresh solutions
Environmental Science & Technology

Manufacturer recalls of toys, promotional drinking glasses, and other children’s products constitute an ongoing “toxic toys crisis” that requires banning potentially harmful ingredients in these products and other changes in policy and practices. Since 2007, the government has recalled more than 17 million toys due to high levels of lead. Monica Becker, Sally Edwards and Rachel Massey say in their report that these and other incidents have raised concern about the problem of toxic substances in toys and other children’s products, many of which are made overseas. The substances include ingredients either suspected or recognized as potentially damaging to children’s health. The authors recommend several actions for the government, including banning or restricting the use of all substances with well-documented toxicity in toys and other children’s products. They also offer recommendations for how the toy industry can be proactive, including establishing an industry-wide list of toxic substances to avoid.

“Thirdhand smoke” may be bigger health hazard than previously believed
Environmental Science & Technology

Yael Dubowski and colleagues note that thirdhand smoke – the invisible remains of cigarette smoke that deposits on carpeting, clothing, furniture and other surfaces – is a newly recognized contributor to the health risks of tobacco and indoor air pollution. Studies show that nicotine in thirdhand smoke can react with the ozone in indoor air and surfaces like clothing and furniture, to form other pollutants. Exposure to them can occur to babies crawling on the carpet, people napping on the sofa, or people eating food tainted by thirdhand smoke. In an effort to learn more about thirdhand smoke, the scientists studied interactions between nicotine and indoor air on a variety of different materials, including cellulose (a component of wood furniture), cotton, and paper to simulate typical indoor surfaces. They found that nicotine interacts with ozone, in indoor air, to form potentially toxic pollutants on these surfaces. “Given the toxicity of some of the identified products and that small particles may contribute to adverse health effects, the present study indicates that exposure to [thirdhand smoke] may pose additional health risks,” the article notes.

First report on fate of underwater dispersants in Deepwater Horizon oil spill
Environmental Science & Technology

Elizabeth Kujawinski and colleagues reported that key chemical components of the 770,000 gallons of oil dispersants applied below the ocean surface in the Deepwater Horizon spill did mix with oil and gas spewing out of the damaged wellhead and remained in the deep ocean for two months or more without degrading. The scientists collected and analyzed seawater samples from the Gulf of Mexico for the presence of a key dispersant ingredient, called DOSS (dioctyl sodium sulfosuccinate), during the active oil flow and again after the flow had ceased. They found DOSS became concentrated in the deepwater plumes of suspended oil and gas at depths of up to three-quarters of a mile and did not mix with the surface applications of dispersant. They also detected the dispersant ingredient at distances of nearly 200 miles from the well two months after deepwater dispersant applications ceased, indicating it was not rapidly biodegraded. Their data are not sufficient to resolve whether the dispersant was effective in dispersing the oil coming out of the wellhead. However, the scientists argue that the persistence of the dispersant over long distances and time periods justifies further study of the effects of chemical dispersant and oil mixture exposure.

Fish smile but some consumers frown at new genre of phosphate-free detergents
Chemical & Engineering News

C&EN Assistant Managing Editor Michael McCoy described how new laws in 16 states require manufacturers to eliminate phosphates from automatic dishwasher detergents sold in the United States. Once hailed as a wonder for making dishes squeaky clean, sodium tripolyphosphate later became a villain in the fight against water pollution. Just like the phosphate fertilizer applied to crops, it kick-starts growth of algae, which die, decay, and deplete oxygen from the water, causing fish kills and other problems. McCoy explains that the well-intentioned phosphate-removal laws, however, have caused an unintended problem for some consumers, leaving dishes and glassware with spots and unsightly films. Detergent manufacturers are now turning to chemists and the chemical industry in a search for phosphate-free formulas that don’t leave dishes dirty. Some manufacturers have already found promising alternatives, while others are testing new detergent ingredients, including polymers and enzymes, that can clean like phosphates without contributing to water pollution.

“Red mud” disaster’s main threat to crops is not toxic metals
Environmental Science & Technology

As farmers in Hungary ponder spring planting on hundreds of acres of farmland affected by last October’s red mud disaster, scientists are reporting that high alkalinity is the main threat to a bountiful harvest, not toxic metals. Erik Smolders and colleagues note that a dam burst at a factory processing aluminum ore, flooding the surrounding land with more than 700,000 cubic yards of a byproduct termed red mud, which contains toxic metals like arsenic, chromium, cadmium and nickel. The mud also contains radioactive elements and is highly alkaline, caustic enough to burn skin and eyes. The scientists’ tests showed that plants in contaminated soil grew about 25 percent slower than crops grown in uncontaminated soil. The main culprit, however, appeared to be not toxic metals or radioactivity, but red mud’s intense alkalinity and salt content. Adding gypsum to the red mud can reduce alkalinity and will accelerate the removal of the salts, the scientists add, recommending long-term monitoring of metals in the crops to remove any concerns with food chain contamination.

Preventing cancer, quite naturally
Chemical & Engineering News

Exciting headlines about the cancer-preventing potential of berries, red wine, and other foods are in the news almost every day. C&EN Associate Editor Carmen Drahl highlights researchers trying to make medicines based on substances in those foods and turn their potential into reality. She notes that scientists have tried for years to develop drugs that reduce the risk of cancer, with only a few successes. So-called “natural products” – chemicals derived from plants and other living organisms – are the basis for almost one-third of today’s prescription medicines. There are a variety of candidates, including resveratrol, a substance found in red wine; abyssinone, a substance found in a plant from traditional Chinese medicine; and potential cancer-preventing substances in deep-ocean microbes. Even though some natural products have failed to prevent cancer in human clinical trials, Drahl cites continued optimism that the search will pay off.

Toward making “extended blood group typing” more widely available
Analytical Chemistry

Christophe Marquette and colleagues are reporting an advance toward enabling more blood banks to adopt so-called “extended blood group typing,” which increases transfusion safety by better matching donors and recipients. Most blood banks still use a century-old blood approach to blood typing, which identifies blood group antigens on red blood cells – proteins that must match in donor and recipient to avoid potentially serious transfusion reactions. Most blood currently is typed for only a few of the 29 known human blood groups, even though some rare blood groups can affect outcomes. Commercial technology does exist for extended typing with DNA tests, but it is expensive, difficult to use, and suited more for research labs than high-volume blood centers. The study describes evaluation of the new more affordable method, called the HiFi Blood 96, which types blood with DNA testing in a high-speed automated procedure. Tests on 293 human blood samples demonstrated the performance and reliability of the new method.

Supercharged proteins enter biology’s forbidden zone
ACS Chemical Biology

David Liu and his colleagues are reporting discovery of a way to help proteins such as the new generation of protein-based drugs – sometimes heralded as tomorrow’s potential “miracle cures” – get past the biochemical “Entrance Forbidden” barrier that keeps them from entering cells and doing their work. Nearly all of the blockbuster drugs that are proteins must do their work on the exterior of cells, activating receptors that send signals to the interior. This constraint greatly limits the scope of protein-based drugs. Liu’s solution: Attaching proteins to molecules of “supercharged” green fluorescent protein, which they mutated to give it a very high positive charge. When the hybrid proteins bump into the surface of a cell, they get pulled inside by negatively charged molecules called proteoglycans. Liu and his team tested the hybrid proteins on five types of cells, and found that the supercharged protein was up to 100 times better at getting proteins into cells compared to other approaches. The delivered proteins were able to go to their target locations in the cell, such as the nucleus or cytoplasm, and perform their jobs.

New insights into link between anti-cholesterol statin drugs and depression
Biochemistry

Amitabha Chattopadhyay and colleagues note in the study that statins (anti-cholesterol drugs) work by blocking a key enzyme involved in the body’s production of cholesterol. Some studies link the drugs to an increased risk of anxiety and depression, but the reasons are unclear. The scientists previously showed that maintaining normal cholesterol levels is important for the function of cell receptors for serotonin, a brain hormone that influences mood and behavior. But the long-term effect of cholesterol depletion on these receptors, which can occur in patients taking anti-cholesterol drugs, is unknown. In lab tests using human serotonin receptors expressed in animal cells, they showed that long-term use of the statin medication mevastatin caused significant changes in the structure and function of serotonin cell receptors. Adding cholesterol to cells treated with mevastatin restored them to normal.

Nano-sized advance toward next big treatment era in dentistry
ACS Nano

Nadia Benkirane-Jessel and colleagues are reporting an advance toward the next big treatment revolution in dentistry – the era in which root canal therapy brings diseased teeth back to life, rather than leaving a “non-vital” or dead tooth in the mouth. They describe a first-of-its-kind, multilayered, nano-sized film – only 1/50,000th the thickness of a human hair containing a substance that could help regenerate dental pulp. Previous studies show that the substance, called alpha melanocyte stimulating hormone, or alpha-MSH, has anti-inflammatory properties. The scientists showed in laboratory tests that alpha-MSH combined with a widely-used polymer produced a material that fights inflammation in fibroblasts, the main type of cell found in dental pulp. Nano-films containing alpha-MSH also increased the number of these cells. This could help revitalize damaged teeth and reduce the need for a root canal procedure, the scientists suggest.

How safe and effective are herbal dietary supplements?
Chemical & Engineering News

Millions of people are taking herbs and other plant-based dietary supplements to improve their health, but they have precious little information on the actual effectiveness or potential ill effects of these products. C&EN Senior Editor Celia Henry Arnaud suggests that consumers are taking a gamble when it comes to the safety and effectiveness of hundreds of pills and potions cluttering store shelves. Scientists are concerned that some supplements, such as black cohosh and red clover, used by menopausal women to reduce hot flashes, and kava, which is used to treat anxiety and insomnia, may contain high levels of toxic metals, such as lead and mercury, or pesticides. There’s also the possibility that the plant itself might be toxic or that a supplement can cause harm by reacting with conventional drugs. The U.S. Food & Drug Administration, which regulates supplements as foods rather than drugs, recently took a step toward improving the situation by requiring all supplement manufacturers to test their products for contaminants. Ongoing research is providing new information that will help address these concerns in the future, including the long-term safety of these products for consumers.

“Nanodragster” races toward the future of molecular machines
Langmuir

James Tour, Kevin Kelly and colleagues are reporting the development of a “nanodragster” that may speed the course toward development of a new generation of futuristic molecular machines. The vehicle – only 1/50,000th the width of a human hair – resembles a hot-rod in shape and can outperform previous nano-sized vehicles. They note that the ability to control the motion of small molecules is essential for building much-anticipated molecular machines, which may find use in manufacturing computer circuits and other electronic components in the future. The new vehicle addresses some of the problems related to the control of its movement. The front end has a smaller axle and wheels made of special materials that roll easier. The rear wheels sport a longer axle but are still made of buckyballs, which provide strong surface grip. These changes result in a “nanodragster” that can operate at lower temperatures than a regular nanocar and possibly has better agility, paving the way for better molecular machines, the scientists say.

New “frozen smoke” material: One ounce could carpet three football fields
ACS Nano

Lei Zhai and colleagues are reporting the development of a new, ultra-light form of aerogel, “frozen smoke” – renowned as the world’s lightest solid material – with amazing strength and an incredibly large surface area. The new so-called “multiwalled carbon nanotube (MCNT) aerogel” could be used in sensors to detect pollutants and toxic substances, chemical reactors, and electronics components. The report describes a process for making MCNT aerogels and tests to determine their properties. Only a few scientists have succeeded in making aerogels from carbon nanotubes, wisps of carbon so small that almost 50,000 would fit across the width of a human hair. The MCNT aerogels also are excellent conductors of electricity, making them ideal for sensing applications, such as sensing as little as 0.003527 ounce of a material resting in the palm of one hand.