Twist-and-glow molecules aid rapid gas detection

Jan 13, 2012
Figure 1: In an emergency situation, rapid detection and identification of air-borne gases is critical to effective decision making by response personnel. Credit: 2011  iStockphoto/mpruitt

In an emergency such as a factory fire, ascertaining which gases are present in the air is critical to preventing or minimizing poisoning (Fig. 1). This requires gas sensors that react quickly and provide a visual signal. However, many existing detection systems work for only one gas, or they use a chemical reaction that is too slow to respond in emergency situations.

Now, Takashi Uemura of Kyoto University and colleagues at several other Japanese institutes, including the RIKEN SPring-8 Center, have created a that works rapidly, emits a clear fluorescent signal, and detects different . Most importantly, the new sensor can distinguish between gases with similar chemical and physical properties.

Uemura and colleagues’ sensor contains so-called ‘flexible porous coordination polymers’ coupled with fluorescent reporter molecules that change structure, and therefore emit signals, according to different gases present in the air. 

“We thought that the incorporation of functional polymers into flexible porous coordination matrices would show unique dynamic properties,” says Uemura. He and his colleagues therefore inserted a fluorescent reporter molecule into the coordination polymer, whereupon the whole combined structure twisted out of shape.

In this normal and twisted state, the fluorescent light from the reporter is quite dim and green. Once gas molecules are introduced, the structure begins to return to its original shape, and the fluorescence returns, brightening as the gas pressure intensifies. For example, the fluorescence changes from green to blue when the molecule adsorbs carbon dioxide.

By this method, the sensor allows regular monitoring of both the type of gas and its concentration in the air. Crucially, the fluorescent response begins within seconds upon interaction with the gas and is complete within minutes, allowing emergency responders to make decisions quickly (Fig. 1).

In addition to these attributes, this is the first such detection system shown to work for gases with almost identical physical properties, the team notes. “Physical properties, such as size, shape, and boiling points, are very similar between carbon dioxide and acetylene, for example, so it is difficult to distinguish between them,” explains Uemura. “Our material has carboxylate sites in the pore, and these sites can bind to acetylene more strongly than carbon dioxide.

“This unique cooperative change of host and guest could allow us to design new advanced materials,” he adds. By investigating different flexible host structures and other ‘guest’ reporter molecules, the researchers believe they could create gas detection systems for a variety of different gases and other applications in the future.

Explore further: Deconstruction of avant-garde cuisine could lead to even more fanciful dishes

More information: Nature Materials 10, 787–793 (2011) doi:10.1038/nmat3104

Related Stories

Flexibility: The key to carbon capture

Aug 12, 2011

From power plants that capture their own carbon dioxide emissions to vehicles powered by hydrogen, clean energy applications often demand materials that can selectively adsorb large volumes of harmful gases. ...

Simultaneous carbon dioxide and oxygen sensing

Jun 21, 2006

Breathing. Birds, do it, bees do it, even educated trees do it. But, only plants can make sugars from the carbon dioxide byproduct and at the same time expel oxygen during photosynthesis. This amazing skill has intrigued ...

Miniature Gas Tank

Jan 28, 2005

Porous networks of organic Van der Waals crystals can selectively store methane and carbon dioxide Washing powders are generally known to consist partially of inorganic zeolites. These aluminosilicates form porous structure ...

Recommended for you

Characterizing an important reactive intermediate

18 hours ago

An international group of researchers led by Dr. Warren E. Piers (University of Calgary) and Dr. Heikki M. Tuononen (University of Jyväskylä) has been able to isolate and characterize an important chemical ...

Surfaces that communicate in bio-chemical Braille

18 hours ago

A Braille-like method that enables medical implants to communicate with a patient's cells could help reduce biomedical and prosthetic device failure rates, according to University of Sydney researchers.

New material steals oxygen from the air

Sep 30, 2014

Researchers from the University of Southern Denmark have synthesized crystalline materials that can bind and store oxygen in high concentrations. Just one spoon of the substance is enough to absorb all the ...

User comments : 0