SCIENCE & TECHNOLOGY
from the SCENEs A selection of stories from C&EN’s six online TOPICAL NEWS CHANNELS
LAYERED DESIGN FOR IMPLANTABLE GLUCOSE SENSORS Blood glucose monitoring would be more convenient for diabetic patients if they had an implantable glucose sensor. Toward that goal, researchers report a novel sensor consisting of a stack of different gel and polymer films that can quickly detect
FROM THE ANALYTICAL SCENE
NOVEL FLUORINATED COMPOUNDS FOUND IN FIREFIGHTERS’ BLOOD
small concentration changes in glucose (Langmuir 2015, DOI: 10.1021/la504358t). Michael C. Leopold of the University of Richmond and his colleagues first deposited a silane gel containing the enzyme glucose oxidase on a platinum electrode. The enzyme reacts with glucose to produce hydrogen peroxide, which oxidizes at the electrode to create a detectable electrical signal. They then added layers of enzyme-free silane gel, polyphenol, and
firefighting foams. Using quadrupole time-of-flight tandem mass spectrometry, the team identified more than 3,000 organic and fluorinated chemicals in the blood samples. A statistical analysis revealed nine fluorinated compounds occurring either exclusively, or at significantly higher levels, in the firefighters’ blood. Four had not
SHUTTERSTOCK
Perfluorinated compounds, such as perfluorooctane sulfonate (PFOS), help firefighting foams rapidly flow over flaming liquids, cooling and quenching fires. Despite environmental and health concerns, researchers don’t know the identity of many of the chemicals in the foams on the market. A new study reports a technique to identify some previously unreported fluorochemicals in foams, using blood samples Firefighting foam contains a complex mix of fluorinated compounds, many of which have not been from firefighters identified by environmental scientists. (Environ. Sci. Technol. 2015, DOI: 10.1021/ es503653n). María José Gómez Ramos been reported previously, and Gómez of the University of Queensland, in Ramos tentatively identified them as Australia, and colleagues compared sulfonic acids analogous to PFOS. She blood samples from 20 firefighters hopes to study the compounds further with those from 20 students and office to determine their toxicities and perworkers who had not been exposed to sistence in the environment.
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polyurethane on top, forming a stacked film several hundred micrometers thick. The polymer layers serve as a size-selective filter, letting glucose through but keeping other larger compounds out. The enzymefree gel layer slows down glucose molecules as they flow into the enzyme-loaded gel, preventing the enzyme from becoming saturated. The layered sensors could detect spikes and drops in glucose concentrations ranging from 8 to 20 µM in 15 to 25 seconds.
FROM THE ENVIRONMENTAL SCENE
THREATENED MUSSELS CUT BACTERIAL CONTAMINATION Reintroducing a threatened freshwater mussel species to streams, estuaries, and lakes could help remove harmful bacteria from the water, according to a new laboratory study (Environ. Sci. Technol. 2015, DOI: 10.1021/es5033212). A team led by Alexandria B. Boehm and Richard G. This threatened Luthy of Stanford Univermussel species sity worked with governcould clean ment officials restoring Escherichia a lake in San Francisco to coli from study whether Anodonta contaminated californiensis, a native mus- urban lakes. sel species, could filter out and digest Escherichia coli from lake water. The researchers added sand and mussels to a 19-L aquarium and just sand to another. On three separate days spread over a period of four weeks, the team pumped lake water through the aquariums and measured E. coli concentrations before and after the lake water passed through the tanks. In the tank without mussels, E. coli concentrations didn’t change. But in the aquarium with mussels, E. coli concentrations fell by roughly 90%. The findings suggest that restoring threatened species could improve not only ecosystems, but also human health, says David C. Love of Johns Hopkins University, who was not involved in the study.
FEBRUARY 23, 2015
RICHARD LUTHY
FROM THE MATERIALS SCENE
