SCIENCE & TECHNOLOGY
from the SCENEs A selection of stories from C&EN’s six online TOPICAL NEWS CHANNELS
FROM THE BIOLOGICAL SCENE
SYNTHETIC POLYSACCHARIDE STABILIZES PROTEINS Chemists have synthesized a novel class of carbohydrate polymers that could help retain the function of enzymes and protein drugs during storage. When researchers freeze-dry proteins for storage, they add saccharides to stabilize the protein structures by promoting hydrogen bonding between the protein and water molecules. Because these saccharides come from natural
FROM THE MATERIALS SCENE
30-µm-tall channel. They then stopped the flow and flashed an ultraviolet light on the chip through a patterned photomask, triggering the material to set as a solid. With the method, the researchers also built a three-dimensional scaffold for growing tissue and a radiofrequency identification (RFID) tag. LANGMUIR
MICROFLUIDIC CHIP FABRICATES INTRICATE POLYMER DESIGNS Microfluidic chips made from polydimethylsiloxane (PDMS) can rapidly and inexpensively produce uniform particles for use in drug delivery or other applications. However, PDMS is soft and can sag if the channel in the chip is more than 100 µm wide. So scientists haven’t been able to produce some larger structures with PDMS microfluidics. Now, Dae Kun Hwang of Ryerson University, in Toronto, and colleagues have developed a high-throughput, low-cost microfluidic method for synthesizing polymer sheets with intricate features (Langmuir 2014, DOI: 10.1021/la501723n). To allow for wider microfluidic channels, Hwang’s team embedded glass slides in PDMS chips to prevent sagging. Using the strengthened chip, they synthesized a membrane by streaming a solution of poly(ethylene glycol)diacrylate and a photoactivated cross-linking agent through an 8-mm-wide and
O sources, researchers have saccharides by combining each no control over the length stabilizer with a batch of lyO N O of the sugar chains, which sozyme and then testing the H NH n affects the molecules’ stabilizaenzyme’s activity after 10 O H H tion ability. To get that control, Mark freeze-thaw cycles. With O OH W. Grinstaff and his colleagues at Boston trehalose, a disaccharide, University developed synthetic polythe enzyme lost about 40% O OH of its prestorage activity. But mers, called poly-amidoOH n = 20–50 saccharides, that consist with the new polymers, the of amide-linked glucose monomers. After protein lost less than 20% (J. Am. Chem. polymerizing chains of 20 to 50 monomers, Soc. 2014, DOI: 10.1021/ja5036804). The the chemists oxidize them to produce negsynthetic polymers performed as well as atively charged polymers. The researchtwo other natural stabilizers, sodium algiers compared the polymers with natural nate and sodium hyaluronate.
Using a microfluidic chip, researchers synthesized a polymer sheet styled after a Pac-Man game.
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JULY 28, 2014
FROM THE ENVIRONMENTAL SCENE
OIL DISPERSANT COMPOUND PERSISTS AFTER GULF SPILL More than four years after the Deepwater Horizon oil spill in 2010, traces of dispersants, the chemicals applied to break up the oil, remain along the Gulf coastline. A dispersant compound, dioctyl sodium sulfosuccinate, also persisted for at least six months after the spill in deep-sea coral communities in the Gulf (Environ. Sci. Technol. Lett. 2014, DOI: 10.1021/ ez500168r). Helen K. White of Haverford College and her colleagues collected and analyzed samples of seafloor sediments around deep-sea corals within 15 miles of the wellhead, weathered oil residue covering one coral community, and oilsoaked sand patties and tar balls that had washed up along the Gulf coastline at seven sites from Louisiana to Florida. White’s team found dioctyl sodium sulfosuccinate in nearly all deep-sea and shoreline samples, accompanied by the signature of oil from the Deepwater Horizon spill. Concentrations ranged from 19 to 9,000 ng/g of sample at the sediment sites and 1 to 260 ng/g along the coastline. White wants to assess the compound’s toxicity to organisms at these concentrations in sediments because little is known about their effects in these contexts.
