Simultaneous carbon dioxide and oxygen sensing

June 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 scientists for decades but separating out the carbon dioxide inputs and outputs while keeping tabs on oxygen levels has always proved difficult.

Now, a new type of chemical sensor, described in the journal Advanced Materials, could change all that. The sensor developed by Otto Wolfbeis and colleagues at the Institute of Analytical Chemistry, Chemo- and Biosensors at the University of Regensburg, Germany, will allow clearer insights into plant respiration and photosynthesis. It could also have application in the food and drink industry as well as in the biotech industry where fermentation and related plant processes are important.

Woflbeis explains that in order to unravel the intricacies of photosynthesis and respiration, two of the most important biochemical processes, scientists have to be able to measure carbon dioxide and oxygen at the same time. He and his team have now found a way to side-step the interference from which all previous sensors suffer. The team first create nanoparticles carrying a fluorescent group that react to light and glow only when they are in contact with carbon dioxide molecules.

These nanoparticles are then embedded in a layer of polymer resin. A second compound that does the same in the presence of oxygen molecules is embedded in a second layer of polymer and the two films sandwich between them a layer of an organometallic compound containing the heavy metal iridium. This layer produces a reference signal for the detection of fluorescence triggered by the two gases. Importantly, however, it is impermeable to oxygen molecules and so its light is not quenched by interference from oxygen.

A blue light-emitting diode (LED) then provides the stimulation for the two sensitive layers to produce light, but only in the presence of their respective gases. A tiny photodetector can then measure the wavelength of light emitted, which is different from each sensor molecule. The strength of the emitted light at each wavelength correlates with the concentration of each of the two gases.

The team tested their sensor over a wide range of different carbon dioxide and oxygen concentrations produced by a growing microbial culture and found it to operate with a remarkable ±5% accuracy at concentration levels expected for real experiments. At much higher but unrealistic concentrations, accuracy deviated only by as much ±10%. Because the device is designed to be reusable rather than a one-shot dip test, the team tested its response after several hundred runs and found it to still be working at these levels of accuracy after 800 runs.

They anticipate that their composite material will become a powerful tool in biological, biotechnological, and medical research. The simultaneous sensor could also have applications in environmental monitoring of sea water and sewage and in medical diagnostics, where blood gas levels are important to understanding the progression of certain diseases.

The research will be commercialized by Presens GmbH.

“It is likely to become a powerful tool in combinatorial microbiology, in cell-based screening for drugs, and in biomonitoring in general," Wolfbeis explains. "In combination with fiber optic microsensors, in vivo sensing of oxygen and carbon dioxide should be possible.”

Citation: Otto Wolfbeis, Composite Material for Simultaneous and Contactless Luminescent Sensing and Imaging of Oxygen and Carbon Dioxide, Advanced Materials 2006, 18, No. 12, 1511–1516, doi: 10.1002/adma.200600120

Source: Advanced Materials

Explore further: Making polymers from a greenhouse gas

Related Stories

Making polymers from a greenhouse gas

July 28, 2015

A future where power plants feed their carbon dioxide directly into an adjacent production facility instead of spewing it up a chimney and into the atmosphere is definitely possible, because CO2 isn't just an undesirable ...

Insights into catalytic converters

July 24, 2015

Modern catalytic converters for the treatment of exhaust gases in vehicles with a combustion engine have largely contributed to reducing of pollutant emissions. By oxidation or reduction, i.e. the donation or acceptance of ...

Tomorrow's farmers may take more fruitful dives for crops

July 11, 2015

We raise crops on land. Could we do the same underwater? Use the oceans to provide alternative sources of plant production where land is not as kind? Why not? asked Fast Company. "The temperature doesn't fluctuate, so there's ...

Where is solar power headed?

July 22, 2015

Most experts agree that to have a shot at curbing the worst impacts of climate change, we need to extricate our society from fossil fuels and ramp up our use of renewable energy.

Recommended for you

Meet the high-performance single-molecule diode

July 29, 2015

A team of researchers from Berkeley Lab and Columbia University has passed a major milestone in molecular electronics with the creation of the world's highest-performance single-molecule diode. Working at Berkeley Lab's Molecular ...

Better together: graphene-nanotube hybrid switches

August 2, 2015

Graphene has been called a wonder material, capable of performing great and unusual material acrobatics. Boron nitride nanotubes are no slackers in the materials realm either, and can be engineered for physical and biological ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.